ENH: error handling for empty surfaces in surfaceFieldValue (#2966)

- for workflows with appearing/disappearing patches (for example)
  can specify that empty surfaces should be ignored or warned about
  instead of raising a FatalError.

  Note that this handling is additional to the regular top-level
  "errors" specification. So specifying 'strict' will only actually
  result in a FatalError if the "errors" does not trap errors.

- "ignore" : any empty surfaces are simply ignored and no
  file output (besides the header).

- "warn" : empty surfaces are warned about a few times (10)
  and the file output contains a NaN entry

- "strict" : corresponds to the default behaviour.
  Throws a FatalError if the surface is empty.
  This error may still be caught by the top-level "errors" handling.

applications/test/ICharStream1/Make/files

@@ -0,0 +1,3 @@
+Test-ICharStream1.C
+
+EXE = $(FOAM_USER_APPBIN)/Test-ICharStream1

applications/test/ICharStream1/Test-ICharStream1.C

@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2017-2018 OpenCFD Ltd.
+    Copyright (C) 2017-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -27,14 +27,46 @@ Description
 
 \*---------------------------------------------------------------------------*/
 
-#include "ListStream.H"
-#include "UListStream.H"
+#include "SpanStream.H"
 #include "wordList.H"
 #include "IOstreams.H"
 #include "argList.H"
 
+#include <cctype>
+#include <cstdio>
+
 using namespace Foam;
 
+Ostream& writeList(Ostream& os, const UList<char>& list)
+{
+    char buf[4];
+    os << list.size() << '(';
+    for (const char c : list)
+    {
+        if (isprint(c))
+        {
+            os << c;
+        }
+        else if (c == '\t')
+        {
+            os << "\\t";
+        }
+        else if (c == '\n')
+        {
+            os << "\\n";
+        }
+        else
+        {
+            ::snprintf(buf, 4, "%02X", c);
+            os << "\\x" << buf;
+        }
+    }
+    os << ')';
+
+    return os;
+}
+
+
 Ostream& toString(Ostream& os, const UList<char>& list)
 {
     os << '"';
@@ -93,7 +125,7 @@ int main(int argc, char *argv[])
     // Buffer storage
     DynamicList<char> storage(16);
 
-    OListStream obuf(std::move(storage));
+    OCharStream obuf(std::move(storage));
     obuf << 1002 << " " << "abcd" << " " << "def" << " " << 3.14159 << ";\n";
 
     // Move contents to output buffer
@@ -104,9 +136,9 @@ int main(int argc, char *argv[])
 
     Info<< "transfer contents to a List" << endl;
 
-    IListStream ibuf;
+    ICharStream ibuf;
 
-    // Reclaim data storage from OListStream -> IListStream
+    // Reclaim data storage from OCharStream -> ICharStream
     {
         List<char> data;
         obuf.swap(data);
@@ -161,6 +193,43 @@ int main(int argc, char *argv[])
     Info<<nl << "swapped out:";
     printInfo(newvalues);
 
+    {
+        iliststream is(std::move(newvalues));
+
+        char c = 0;
+
+        Info<< nl
+            << "getting values from iliststream of "
+            << is.list() << endl;
+
+        // Info<< " (" << is.tellg() << " " << is.remaining() << ")";
+        // Info<< "get:";
+        while (is.get(c))
+        {
+            Info<< ' ' << c;
+            // Info<< " (" << is.tellg() << " " << is.remaining() << ")";
+        }
+        Info<< " - end" << nl;
+
+        // Info<< "remaining: " << is.list() << endl;
+        // Info<< "remaining: " << is.remaining() << endl;
+
+        // Manipulate the list view
+        {
+            UList<char> chars(is.list());
+            Foam::reverse(chars);
+        }
+
+        is.rewind();
+
+        Info<< "get:";
+        while (is.get(c))
+        {
+            Info<< ' ' << c;
+        }
+        Info<< " - end" << nl;
+    }
+
     Info<< "\nEnd\n" << endl;
 
     return 0;

applications/test/IFstream/Test-IFstream.C

@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2020 OpenCFD Ltd.
+    Copyright (C) 2020-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -33,6 +33,7 @@ Description
 
 #include "argList.H"
 #include "Fstream.H"
+#include "OSspecific.H"
 #include "etcFiles.H"
 
 using namespace Foam;
@@ -44,11 +45,14 @@ int main(int argc, char *argv[])
 {
     argList::noBanner();
     argList::noParallel();
+    argList::noParallel();
+    argList::addOption("ignore", "file", "Test readRaw with ignore");
 
     #include "setRootCase.H"
 
     // Test with etc/controlDict (mandatory, from distribution)
 
+    if (!args.found("ignore"))
     {
         const fileName inputFile
         (
@@ -97,6 +101,43 @@ int main(int argc, char *argv[])
         }
     }
 
+    fileName testFile;
+    if (args.readIfPresent("ignore", testFile))
+    {
+        if (testFile.has_ext("gz"))
+        {
+            testFile.remove_ext();
+            Info<< "stripping extraneous .gz ending" << endl;
+        }
+
+        IFstream is(testFile);
+        auto& stdStream = is.stdStream();
+
+        List<char> buffer(1000);
+
+        Info<< "Test readRaw with: " << is.name()
+            << " compressed:" << int(is.compression())
+            << " file-size:" << is.fileSize() << nl;
+
+        for (int iter = 0; is.good() && iter < 1000; ++iter)
+        {
+            Info<< "iter:" << iter;
+            if (iter % 2)
+            {
+                Info<< " [read]  ";
+                is.readRaw(buffer.data(), buffer.size());
+            }
+            else
+            {
+                Info<< " [ignore]";
+                is.readRaw(nullptr, buffer.size() / 2);
+            }
+
+            Info<< " : " << stdStream.gcount() << endl;
+        }
+    }
+
+
     Info<< "\nEnd\n" << endl;
     return 0;
 }

applications/test/IListStream/Make/files

@@ -1,3 +0,0 @@
-Test-IListStream.C
-
-EXE = $(FOAM_USER_APPBIN)/Test-IListStream

applications/test/ITstream/Test-ITstream.C

@@ -28,8 +28,6 @@ Description
 \*---------------------------------------------------------------------------*/
 
 #include "argList.H"
-#include "ListStream.H"
-#include "UListStream.H"
 #include "wordList.H"
 #include "IOstreams.H"
 #include "argList.H"

applications/test/OCharStream1/Make/files

@@ -0,0 +1,3 @@
+Test-OCharStream1.C
+
+EXE = $(FOAM_USER_APPBIN)/Test-OCharStream1

applications/test/OCharStream1/Test-OCharStream1.C

@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2017-2021 OpenCFD Ltd.
+    Copyright (C) 2017-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -27,13 +27,46 @@ Description
 
 \*---------------------------------------------------------------------------*/
 
-#include "ListStream.H"
+#include "SpanStream.H"
 #include "wordList.H"
 #include "IOstreams.H"
 #include "argList.H"
 
+#include <cctype>
+#include <cstdio>
+
 using namespace Foam;
 
+Ostream& writeList(Ostream& os, const UList<char>& list)
+{
+    char buf[4];
+    os << list.size() << '(';
+    for (const char c : list)
+    {
+        if (isprint(c))
+        {
+            os << c;
+        }
+        else if (c == '\t')
+        {
+            os << "\\t";
+        }
+        else if (c == '\n')
+        {
+            os << "\\n";
+        }
+        else
+        {
+            ::snprintf(buf, 4, "%02X", c);
+            os << "\\x" << buf;
+        }
+    }
+    os << ')';
+
+    return os;
+}
+
+
 Ostream& toString(Ostream& os, const UList<char>& list)
 {
     os << '"';
@@ -91,12 +124,12 @@ void outputDict(OS& os)
 
 int main(int argc, char *argv[])
 {
+    #include "setRootCase.H"
+
     // Buffer storage
     DynamicList<char> storage(16);
 
-    OListStream obuf(std::move(storage));
-
-    obuf.setBlockSize(100);
+    OCharStream obuf(std::move(storage));
 
     printInfo(obuf);
 
@@ -140,10 +173,10 @@ int main(int argc, char *argv[])
     Info<<"after overwrite" << nl;
     printInfo(obuf);
 
-    Info<< "transfer contents to a List or IListStream" << nl;
+    Info<< "transfer contents to a List or ICharStream" << nl;
 
-    IListStream ibuf;
-    // Reclaim data storage from OListStream -> IListStream
+    ICharStream ibuf;
+    // Reclaim data storage from OCharStream -> ICharStream
     {
         List<char> data;
         obuf.swap(data);
@@ -169,7 +202,7 @@ int main(int argc, char *argv[])
         Info<<"input:";
         toString(Info, list) << endl;
 
-        OListStream buf1(std::move(list));
+        OCharStream buf1(std::move(list));
 
         Info<<"orig:";
         toString(Info, list) << endl;
@@ -204,7 +237,7 @@ int main(int argc, char *argv[])
 
     Info<< nl << "Test dictionary" << nl;
     {
-        OListStream os1;
+        OCharStream os1;
 
         outputDict(os1);
 
@@ -213,7 +246,7 @@ int main(int argc, char *argv[])
     }
 
     {
-        OListStream os2;
+        OCharStream os2;
         os2.indentSize(0);
 
         outputDict(os2);

applications/test/OCountStream/Test-OCountStream.C

@@ -74,7 +74,7 @@ int main(int argc, char *argv[])
 
     Info<< "counter state: " << (cnt.stdStream().rdstate()) << nl
         << "via string-stream: " << str.str().size() << " chars" << nl
-        << "via ocountstream: " << plain.size() << " chars" << endl;
+        << "via ocountstream: " << plain.count() << " chars" << endl;
 
     fileName outputName;
     args.readIfPresent("write", outputName);

applications/test/OListStream/Make/files

@@ -1,3 +0,0 @@
-Test-OListStream.C
-
-EXE = $(FOAM_USER_APPBIN)/Test-OListStream

applications/test/SpanStream1/Make/files

@@ -0,0 +1,3 @@
+Test-SpanStream1.C
+
+EXE = $(FOAM_USER_APPBIN)/Test-SpanStream1

applications/test/SpanStream1/Test-SpanStream1.C

@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2017-2018 OpenCFD Ltd.
+    Copyright (C) 2017-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -27,16 +27,48 @@ Description
 
 \*---------------------------------------------------------------------------*/
 
-#include "UListStream.H"
+#include "SpanStream.H"
 #include "wordList.H"
 #include "IOstreams.H"
 #include "argList.H"
 
+#include <cctype>
+#include <cstdio>
 #include <sstream>
 #include <vector>
 
 using namespace Foam;
 
+Ostream& writeList(Ostream& os, const UList<char>& list)
+{
+    char buf[4];
+    os << list.size() << '(';
+    for (const char c : list)
+    {
+        if (isprint(c))
+        {
+            os << c;
+        }
+        else if (c == '\t')
+        {
+            os << "\\t";
+        }
+        else if (c == '\n')
+        {
+            os << "\\n";
+        }
+        else
+        {
+            ::snprintf(buf, 4, "%02X", c);
+            os << "\\x" << buf;
+        }
+    }
+    os << ')';
+
+    return os;
+}
+
+
 Ostream& toString(Ostream& os, const UList<char>& list)
 {
     os << '"';
@@ -108,7 +140,7 @@ int main(int argc, char *argv[])
     // Buffer storage
     DynamicList<char> storage(1000);
 
-    UOListStream obuf(storage);
+    OSpanStream obuf(storage);
     obuf << 1002 << "\n" << "abcd" << "\n" << "def" << "\n" << 3.14159 << ";\n";
 
     obuf.print(Info);
@@ -120,7 +152,7 @@ int main(int argc, char *argv[])
 
     // Attach input buffer - could also do without previous resize
     {
-        UIListStream ibuf(storage);
+        ISpanStream ibuf(storage);
 
         printTokens(ibuf);
 
@@ -135,13 +167,21 @@ int main(int argc, char *argv[])
     {
         Info<< "parse as std::istream\n";
 
-        uiliststream is(storage.cdata(), storage.size());
+        ispanstream is(storage.cdata(), storage.size());
+
+        Info<< "input: ";
+        writeList(Info, is.list()) << endl;
+
+        Info<< "where: "  << is.tellg() << endl;
+        Info<< "capacity: " << is.capacity() << endl;
+        Info<< "total: " << is.capacity() << endl;
 
         string tok;
 
         while (std::getline(is, tok))
         {
             std::cerr << "tok: " << tok << nl;
+            Info<< "where: "  << is.tellg() << endl;
         }
 
         Info<< nl << "Repeat..." << endl;
@@ -170,7 +210,7 @@ int main(int argc, char *argv[])
         toString(Info, chars);
         Info<< "----" << nl;
 
-        uiliststream is(chars.data(), chars.size());
+        ispanstream is(chars.data(), chars.size());
         string tok;
         std::cerr<< nl << "Parsed..." << nl;
         while (std::getline(is, tok))

applications/test/UIListStream/Make/files

@@ -1,3 +0,0 @@
-Test-UIListStream.C
-
-EXE = $(FOAM_USER_APPBIN)/Test-UIListStream

applications/test/primitives/Test-primitives.C

@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2017-2022 OpenCFD Ltd.
+    Copyright (C) 2017-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -33,7 +33,7 @@ Description
 
 #include "scalar.H"
 #include "FlatOutput.H"
-#include "ListStream.H"
+#include "SpanStream.H"
 #include "StringStream.H"
 #include "NASCore.H"
 #include "parsing.H"
@@ -443,22 +443,22 @@ int main(int argc, char *argv[])
             << " read " << sizeof(scalar) << nl;
 
         List<otherType> srcList(15);
+
         forAll(srcList, i)
         {
             srcList[i] = 1 + 10*i;
         }
 
-        DynamicList<char> buf;
-
-        OListStream os(std::move(buf), IOstreamOption::BINARY);
+        OCharStream os(IOstreamOption::BINARY);
         os << srcList;
 
-        os.swap(buf); // Recover buffer
+        DynamicList<char> buf;
+        os.swap(buf);  // Recover written contents
 
         // Read back
         List<scalar> dstList;
 
-        UIListStream is(buf, IOstreamOption::BINARY);
+        ISpanStream is(buf, IOstreamOption::BINARY);
         is.setScalarByteSize(sizeof(otherType));
 
         Info<< "Stream scalar-size ("

applications/test/readBroadcast1/Make/files

@@ -0,0 +1,3 @@
+Test-readBroadcast1.C
+
+EXE = $(FOAM_USER_APPBIN)/Test-readBroadcast1

applications/test/readBroadcast1/Make/options

@@ -0,0 +1,2 @@
+/* EXE_INC = */
+/* EXE_LIBS = */

applications/test/readBroadcast1/Test-readBroadcast1.C

@@ -0,0 +1,297 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | www.openfoam.com
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+    Copyright (C) 2023 OpenCFD Ltd.
+-------------------------------------------------------------------------------
+License
+    This file is part of OpenFOAM.
+
+    OpenFOAM is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+    for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
+
+Description
+    Test file reading with broadcast
+
+\*---------------------------------------------------------------------------*/
+
+#include "argList.H"
+#include "OSspecific.H"  // For fileSize()
+#include "Fstream.H"
+#include "Pstream.H"
+#include "SpanStream.H"
+#include <limits>
+
+using namespace Foam;
+
+// * * * * * * * * * * * * * * * Local Functions * * * * * * * * * * * * * * //
+
+bool optUseSeek = false;
+bool optVerbose = false;
+
+// Get file contents. Usually master-only and broadcast
+static List<char> slurpFile
+(
+    const fileName& pathname,
+    const bool parallel = UPstream::parRun(),
+    const bool masterOnly = true
+)
+{
+    Info<< "slurp master-only:" << masterOnly
+        << " broadcast:" << (masterOnly && parallel)
+        << " seek:" << optUseSeek
+        << " file: " << pathname << nl;
+
+    if (optUseSeek)
+    {
+        Info<< "Rewinding gzstream does not work..." << nl;
+    }
+
+    // -------------------------
+
+    List<char> buffer;
+
+    ifstreamPointer ifp;
+
+    if (UPstream::master() || !masterOnly)
+    {
+        ifp.open(pathname);
+    }
+
+    if (ifp && ifp->good())
+    {
+        Info<< "compressed:"
+            << (IOstreamOption::COMPRESSED == ifp.whichCompression()) << nl;
+
+        #if 0
+        uint64_t inputSize = Foam::fileSize(pathname);
+
+        if (IOstreamOption::COMPRESSED == ifp.whichCompression())
+        {
+            ifp->ignore(std::numeric_limits<std::streamsize>::max());
+
+            const std::streamsize nread = ifp->gcount();
+
+            if (nread == std::numeric_limits<std::streamsize>::max())
+            {
+                FatalErrorInFunction
+                    << "Failed call to ignore()" << nl
+                    << exit(FatalError);
+            }
+            inputSize = ifp->gcount();
+
+            if (optUseSeek)
+            {
+                // Rewinding gzstream does not really work...
+                ifp->rdbuf()->pubseekpos(0, std::ios_base::in);
+            }
+            else
+            {
+                // Open it again - gzstream rewinding is unreliable...
+                ifp.open(pathname);
+            }
+        }
+
+        buffer.resize(label(inputSize));
+        ifp->read(buffer.data(), buffer.size_bytes());
+
+        const std::streamsize nread = ifp->gcount();
+
+        if (nread == std::numeric_limits<std::streamsize>::max())
+        {
+            FatalErrorInFunction
+                << "Failed call to read()" << nl
+                << exit(FatalError);
+        }
+
+        buffer.resize(label(nread));  // Extra safety (paranoid)
+
+        #else
+
+        if (IOstreamOption::COMPRESSED == ifp.whichCompression())
+        {
+            // For compressed files we do not have any idea how large
+            // the result will be. So read chunk-wise.
+            // Using the compressed size for the chunk size:
+            // 50% compression = 2 iterations
+            // 66% compression = 3 iterations
+            // ...
+
+            const auto inputSize = Foam::fileSize(pathname + ".gz");
+
+            const uint64_t chunkSize =
+            (
+                (inputSize <= 1024)
+              ? uint64_t(4096)
+              : uint64_t(2*inputSize)
+            );
+
+            uint64_t beg = 0;
+
+            bool normalExit = false;
+
+            for (int iter = 1; iter < 100000; ++iter)
+            {
+                if (optVerbose)
+                {
+                    Info<< "iter " << iter << nl;
+                    Info<< "chunk " << label(chunkSize) << nl;
+                    Info<< "size " << label(iter * chunkSize) << nl;
+                }
+
+                buffer.resize(label(iter * chunkSize));
+                ifp->read(buffer.data() + beg, chunkSize);
+
+                const std::streamsize nread = ifp->gcount();
+
+                if (optVerbose)
+                {
+                    Info<< "nread: " << nread << nl;
+                }
+
+                if
+                (
+                    nread < 0
+                 || nread == std::numeric_limits<std::streamsize>::max()
+                )
+                {
+                    if (iter == 0)
+                    {
+                        FatalErrorInFunction
+                            << "Failed call to read()" << nl
+                            << exit(FatalError);
+                    }
+                    break;
+                }
+                else
+                {
+                    beg += uint64_t(nread);
+                    if (nread >= 0 && uint64_t(nread) < chunkSize)
+                    {
+                        normalExit = true;
+                        if (optVerbose)
+                        {
+                            Info<< "stopped after "
+                                << iter << " iterations" << nl;
+                        }
+                        buffer.resize(label(beg));
+                        break;
+                    }
+                }
+            }
+
+            if (!normalExit)
+            {
+                FatalErrorInFunction
+                    << "Abnormal exit" << nl
+                    << exit(FatalError);
+            }
+        }
+        else
+        {
+            const auto inputSize = Foam::fileSize(pathname);
+
+            if (inputSize >= 0)
+            {
+                buffer.resize(label(inputSize));
+                ifp->read(buffer.data(), buffer.size_bytes());
+
+                const std::streamsize nread = ifp->gcount();
+
+                if
+                (
+                    nread < 0
+                 || nread == std::numeric_limits<std::streamsize>::max()
+                )
+                {
+                    FatalErrorInFunction
+                        << "Failed call to read()" << nl
+                        << exit(FatalError);
+                }
+
+                buffer.resize(label(nread));  // Extra safety (paranoid)
+            }
+        }
+        #endif
+    }
+
+    // Done with input file
+    ifp.reset(nullptr);
+
+    if (parallel && masterOnly)
+    {
+        // On the assumption of larger files,
+        // prefer two broadcasts instead of serialization
+        Pstream::broadcastList(buffer);
+    }
+
+    return buffer;
+}
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+// Main program:
+
+int main(int argc, char *argv[])
+{
+    argList::noBanner();
+    argList::noFunctionObjects();
+    argList::noCheckProcessorDirectories();
+    argList::addBoolOption("seek", "seek with gzstream (fails!)");
+    argList::addVerboseOption("addition information");
+    argList::addBoolOption("seek", "seek with gzstream");
+    argList::addBoolOption("no-broadcast", "suppress broadcast contents");
+
+    argList::addNote("Test master-only reading (with broadcast)");
+
+    argList::addArgument("srcFile");
+
+    #include "setRootCase.H"
+
+    const bool syncPar = (UPstream::parRun() && !args.found("no-broadcast"));
+    optUseSeek = args.found("seek");
+    optVerbose = args.verbose();
+
+    auto srcName = args.get<fileName>(1);
+
+    if (srcName.has_ext("gz"))
+    {
+        srcName.remove_ext();
+        Info<< "stripping extraneous .gz ending" << endl;
+    }
+
+    ICharStream is;
+
+    {
+        List<char> buffer(slurpFile(srcName, syncPar));
+
+        is.swap(buffer);
+    }
+
+    Pout<< "input:" << is.capacity() << endl;
+
+    for (string line; is.getLine(line); /*nil*/)
+    {
+        Pout<< "L:" << is.lineNumber() << ": " << line.c_str() << nl;
+    }
+
+    Info<< "\nEnd\n" << endl;
+
+    return 0;
+}
+
+
+// ************************************************************************* //

src/OpenFOAM/Make/files

@@ -271,7 +271,7 @@ gzstream = $(Streams)/gzstream
 $(gzstream)/gzstream.C
 
 memstream = $(Streams)/memory
-$(memstream)/ListStream.C
+$(memstream)/SpanStreams.C
 
 Fstreams = $(Streams)/Fstreams
 $(Fstreams)/IFstream.C

src/OpenFOAM/containers/Lists/FixedList/FixedList.C

@@ -46,24 +46,31 @@ std::streamsize Foam::FixedList<T, N>::byteSize()
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
 template<class T, unsigned N>
-Foam::label Foam::FixedList<T, N>::find(const T& val, label pos) const
+Foam::label Foam::FixedList<T, N>::find
+(
+    const T& val,
+    label pos,
+    label len
+) const
 {
-    if (pos >= 0)
+    if (pos >= 0 && pos < label(N))
     {
-        // auto iter = std::find(this->begin(pos), this->end(), val);
-        // if (iter != this->end())
-        // {
-        //     return label(iter - this->begin());
-        // }
+        // Change length to end iterator position
+        // len == -1 has same meaning as std::string::npos - search until end
 
-        while (pos < label(N))
+        if (len > 0) len += pos;
+        if (len < 0 || len > label(N))
         {
-            if (this->v_[pos] == val)
-            {
-                return pos;
-            }
+            len = label(N);
+        }
 
-            ++pos;
+        auto iter = (this->cbegin() + pos);
+        const auto lastIter = (this->cbegin() + len);
+
+        iter = std::find(iter, lastIter, val);
+        if (iter != lastIter)
+        {
+            return label(iter - this->begin());
         }
     }
 

src/OpenFOAM/containers/Lists/FixedList/FixedList.H

@@ -276,10 +276,11 @@ public:
     // Search
 
         //- Find index of the first occurrence of the value.
-        //  Any occurrences before the start pos are ignored.
-        //  Linear search.
-        //  \return -1 if not found.
-        label find(const T& val, label pos = 0) const;
+        //  \param val The value to search for
+        //  \param pos The first position to examine (default: 0, -ve no-op)
+        //  \param len The length of the search region (-ve until the end)
+        //  \return position in list or -1 if not found.
+        label find(const T& val, label pos = 0, label len = -1) const;
 
         //- Find index of the last occurrence of the value.
         //  Any occurrences after the end pos are ignored.
@@ -288,10 +289,11 @@ public:
         label rfind(const T& val, label pos = -1) const;
 
         //- Is the value contained in the list?
-        //  Linear search from start pos until the end of the list.
-        //  Any occurrences before the start pos are ignored.
+        //  \param val The value to search for
+        //  \param pos The first position to examine (default: 0, -ve no-op)
+        //  \param len The length of the search region (-ve until the end)
         //  \return true if found.
-        inline bool contains(const T& val, label pos = 0) const;
+        inline bool contains(const T& val, label pos = 0, label len = -1) const;
 
 
     // Edit

src/OpenFOAM/containers/Lists/FixedList/FixedListI.H

@@ -307,9 +307,14 @@ inline bool Foam::FixedList<T, N>::uniform() const
 
 
 template<class T, unsigned N>
-inline bool Foam::FixedList<T, N>::contains(const T& val, label pos) const
+inline bool Foam::FixedList<T, N>::contains
+(
+    const T& val,
+    label pos,
+    label len
+) const
 {
-    return (this->find(val, pos) >= 0);
+    return (this->find(val, pos, len) >= 0);
 }
 
 

src/OpenFOAM/containers/Lists/List/UList.C

@@ -177,26 +177,26 @@ std::streamsize Foam::UList<T>::byteSize() const
 
 
 template<class T>
-Foam::label Foam::UList<T>::find(const T& val, label pos) const
+Foam::label Foam::UList<T>::find(const T& val, label pos, label len) const
 {
-    const label len = this->size();
-
-    if (pos >= 0)
+    if (pos >= 0 && pos < this->size())
     {
-        // auto iter = std::find(this->begin(pos), this->end(), val);
-        // if (iter != this->end())
-        // {
-        //     return label(iter - this->begin());
-        // }
+        // Change length to end iterator position
+        // len == -1 has same meaning as std::string::npos - search until end
 
-        while (pos < len)
+        if (len > 0) len += pos;
+        if (len < 0 || len > this->size())
         {
-            if (this->v_[pos] == val)
-            {
-                return pos;
-            }
+            len = this->size();
+        }
 
-            ++pos;
+        auto iter = (this->cbegin() + pos);
+        const auto lastIter = (this->cbegin() + len);
+
+        iter = std::find(iter, lastIter, val);
+        if (iter != lastIter)
+        {
+            return label(iter - this->begin());
         }
     }
 

src/OpenFOAM/containers/Lists/List/UList.H

@@ -319,10 +319,11 @@ public:
     // Search
 
         //- Find index of the first occurrence of the value.
-        //  Any occurrences before the start pos are ignored.
-        //  Linear search.
+        //  \param val The value to search for
+        //  \param pos Initial position to examine (default: 0, -ve no-op)
+        //  \param len The length of the search region (-ve until the end)
         //  \return position in list or -1 if not found.
-        label find(const T& val, label pos = 0) const;
+        label find(const T& val, label pos = 0, label len = -1) const;
 
         //- Find index of the last occurrence of the value.
         //  Any occurrences after the end pos are ignored.
@@ -331,10 +332,11 @@ public:
         label rfind(const T& val, label pos = -1) const;
 
         //- Is the value contained in the list?
-        //  Linear search from start pos until the end of the list.
-        //  Any occurrences before the start pos are ignored.
+        //  \param val The value to search for
+        //  \param pos The first position to examine (default: 0, -ve no-op)
+        //  \param len The length of the search region (-ve until the end)
         //  \return true if found.
-        inline bool contains(const T& val, label pos = 0) const;
+        inline bool contains(const T& val, label pos = 0, label len = -1) const;
 
 
     // Edit

src/OpenFOAM/containers/Lists/List/UListI.H

@@ -304,9 +304,9 @@ inline std::streamsize Foam::UList<T>::size_bytes() const noexcept
 
 
 template<class T>
-inline bool Foam::UList<T>::contains(const T& val, label pos) const
+inline bool Foam::UList<T>::contains(const T& val, label pos, label len) const
 {
-    return (this->find(val, pos) >= 0);
+    return (this->find(val, pos, len) >= 0);
 }
 
 

src/OpenFOAM/db/IOobjects/decomposedBlockData/decomposedBlockData.C

@@ -37,7 +37,7 @@ License
 #include "charList.H"
 #include "labelPair.H"
 #include "masterUncollatedFileOperation.H"
-#include "ListStream.H"
+#include "SpanStream.H"
 #include "StringStream.H"
 
 // * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
@@ -403,7 +403,7 @@ Foam::decomposedBlockData::readBlock
 
     if (blocki == 0)
     {
-        realIsPtr.reset(new IListStream(std::move(data)));
+        realIsPtr.reset(new ICharStream(std::move(data)));
         realIsPtr->name() = is.name();
 
         {
@@ -422,7 +422,7 @@ Foam::decomposedBlockData::readBlock
     {
         {
             // Read header from first block
-            UIListStream headerStream(data);
+            ISpanStream headerStream(data);
             if (!headerIO.readHeader(headerStream))
             {
                 FatalIOErrorInFunction(headerStream)
@@ -440,7 +440,7 @@ Foam::decomposedBlockData::readBlock
             // Read and discard data, only retain the last one
             decomposedBlockData::readBlockEntry(is, data);
         }
-        realIsPtr.reset(new IListStream(std::move(data)));
+        realIsPtr.reset(new ICharStream(std::move(data)));
         realIsPtr->name() = is.name();
 
         // Apply stream settings
@@ -585,7 +585,7 @@ Foam::autoPtr<Foam::ISstream> Foam::decomposedBlockData::readBlocks
         // Read master data
         decomposedBlockData::readBlockEntry(is, data);
 
-        realIsPtr.reset(new IListStream(std::move(data)));
+        realIsPtr.reset(new ICharStream(std::move(data)));
         realIsPtr->name() = fName;
 
         {
@@ -639,7 +639,7 @@ Foam::autoPtr<Foam::ISstream> Foam::decomposedBlockData::readBlocks
             );
             is >> data;
 
-            realIsPtr.reset(new IListStream(std::move(data)));
+            realIsPtr.reset(new ICharStream(std::move(data)));
             realIsPtr->name() = fName;
         }
     }
@@ -673,7 +673,7 @@ Foam::autoPtr<Foam::ISstream> Foam::decomposedBlockData::readBlocks
             UIPstream is(UPstream::masterNo(), pBufs);
             is >> data;
 
-            realIsPtr.reset(new IListStream(std::move(data)));
+            realIsPtr.reset(new ICharStream(std::move(data)));
             realIsPtr->name() = fName;
         }
     }
@@ -1090,7 +1090,7 @@ bool Foam::decomposedBlockData::writeData(Ostream& os) const
     // Re-read my own data to find out the header information
     if (Pstream::master(comm_))
     {
-        UIListStream headerStream(contentData_);
+        ISpanStream headerStream(contentData_);
         io.readHeader(headerStream);
 
         verValue = headerStream.version().canonical();

src/OpenFOAM/db/IOobjects/decomposedBlockData/decomposedBlockDataHeader.C

@@ -29,7 +29,7 @@ License
 #include "dictionary.H"
 #include "foamVersion.H"
 #include "objectRegistry.H"
-#include "ListStream.H"
+#include "SpanStream.H"
 
 // * * * * * * * * * * * * * * * Local Functions * * * * * * * * * * * * * * //
 
@@ -125,7 +125,7 @@ bool Foam::decomposedBlockData::readHeader(IOobject& io, Istream& is)
             List<char> charData;
             decomposedBlockData::readBlockEntry(is, charData);
 
-            UIListStream headerStream(charData);
+            ISpanStream headerStream(charData);
             headerStream.name() = is.name();
 
             ok = io.readHeader(headerStream);

src/OpenFOAM/db/IOstreams/Fstreams/IFstream.C

@@ -27,7 +27,7 @@ License
 \*---------------------------------------------------------------------------*/
 
 #include "IFstream.H"
-#include "OSspecific.H"
+#include "OSspecific.H"  // For isFile(), fileSize()
 
 // * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
 
@@ -91,6 +91,45 @@ Foam::IFstream::IFstream
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
+std::streamsize Foam::IFstream::fileSize() const
+{
+    const std::istream* ptr = ifstreamPointer::get();
+
+    if (!ptr || this->name().empty())
+    {
+        return std::streamsize(-1);
+    }
+
+    off_t fileLen = -1;
+
+    if (IOstreamOption::COMPRESSED == ifstreamPointer::whichCompression())
+    {
+        fileLen = Foam::fileSize(this->name() + ".gz");
+    }
+    else
+    {
+        // TBD: special handing for wrapped icharstream
+        // if
+        // (
+        //     const Foam::icharstream* charstr
+        //   = dynamic_cast<const Foam::icharstream*>(ptr)>(ptr)
+        // )
+        // {
+        //     return charstr->capacity();
+        // }
+
+        fileLen = Foam::fileSize(this->name());
+    }
+
+    if (fileLen >= 0)
+    {
+        return std::streamsize(fileLen);
+    }
+
+    return std::streamsize(-1);
+}
+
+
 std::istream& Foam::IFstream::stdStream()
 {
     std::istream* ptr = ifstreamPointer::get();

src/OpenFOAM/db/IOstreams/Fstreams/IFstream.H

@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011 OpenFOAM Foundation
-    Copyright (C) 2017-2021 OpenCFD Ltd.
+    Copyright (C) 2017-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -94,6 +94,13 @@ public:
         //- Read/write access to the name of the stream
         using ISstream::name;
 
+        //- Return the size of the underlying file (-1 on error).
+        //- This corresponds to Foam::fileSize() but with extra handling of
+        //- compressed files.
+        //  The return type is \c std::streamsize instead of \c off_t.
+        //  \note Use sparingly since it involves a file stat()!
+        std::streamsize fileSize() const;
+
 
     // STL stream
 

src/OpenFOAM/db/IOstreams/Sstreams/ISstream.C

@@ -1051,20 +1051,7 @@ Foam::Istream& Foam::ISstream::readRaw(char* data, std::streamsize count)
         }
         else
         {
-            // Forward seek
-            // - use absolute positioning (see C++ notes about std::ifstream)
-            is_.seekg(is_.tellg() + std::istream::pos_type(count));
-
-            // Not sure if this is needed (as per rewind)
-            // some documentation indicates that ifstream needs
-            // seekg with values from a tellg
-            //
-            // stdStream().rdbuf()->pubseekpos
-            // (
-            //     count,
-            //     std::ios_base::seekdir::cur,
-            //     std::ios_base::in
-            // );
+            is_.ignore(count);
         }
     }
     syncState();
@@ -1102,8 +1089,11 @@ void Foam::ISstream::rewind()
     stdStream().clear();  // Clear the iostate error state flags
     setGood();            // Sync local copy of iostate
 
-    // pubseekpos() rather than seekg() so that it works with gzstream
     stdStream().rdbuf()->pubseekpos(0, std::ios_base::in);
+
+    // NOTE: this form of rewind does not work with igzstream.
+    // However, igzstream is usually wrapped as IFstream which has its
+    // own dedicated rewind treatment for igzstream.
 }
 
 

src/OpenFOAM/db/IOstreams/Sstreams/ISstreamI.H

@@ -76,9 +76,10 @@ inline int Foam::ISstream::peek()
 inline Foam::ISstream& Foam::ISstream::getLine(std::string& str, char delim)
 {
     std::getline(is_, str, delim);
+    std::streamsize count = is_.gcount();
     syncState();
 
-    if (delim == '\n')
+    if (delim == '\n' && count > 0)
     {
         ++lineNumber_;
     }
@@ -90,11 +91,10 @@ inline Foam::ISstream& Foam::ISstream::getLine(std::string& str, char delim)
 inline std::streamsize Foam::ISstream::getLine(std::nullptr_t, char delim)
 {
     is_.ignore(std::numeric_limits<std::streamsize>::max(), delim);
+    std::streamsize count = is_.gcount();
     syncState();
 
-    std::streamsize count = is_.gcount();
-
-    if (delim == '\n' && count)
+    if (delim == '\n' && count > 0)
     {
         ++lineNumber_;
     }

src/OpenFOAM/db/IOstreams/StringStreams/StringStream.H

@@ -259,7 +259,6 @@ public:
         //- Rewind the output stream
         virtual void rewind()
         {
-            // pubseekpos() instead of seekp() for symmetry with other classes
             stream_.rdbuf()->pubseekpos(0, std::ios_base::out);
         }
 

src/OpenFOAM/db/IOstreams/Tstreams/ITstream.C

@@ -28,8 +28,8 @@ License
 
 #include "error.H"
 #include "ITstream.H"
+#include "SpanStream.H"
 #include "StringStream.H"
-#include "UIListStream.H"
 #include <memory>
 
 // * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
@@ -94,7 +94,7 @@ Foam::tokenList Foam::ITstream::parse
     IOstreamOption streamOpt
 )
 {
-    UIListStream is(input, streamOpt);
+    ISpanStream is(input, streamOpt);
 
     tokenList tokens;
     parseStream(is, tokens);
@@ -108,7 +108,7 @@ Foam::tokenList Foam::ITstream::parse
     IOstreamOption streamOpt
 )
 {
-    UIListStream is(input.data(), input.length(), streamOpt);
+    ISpanStream is(input, streamOpt);
 
     tokenList tokens;
     parseStream(is, tokens);
@@ -122,7 +122,7 @@ Foam::tokenList Foam::ITstream::parse
     IOstreamOption streamOpt
 )
 {
-    UIListStream is(input, strlen(input), streamOpt);
+    ISpanStream is(input, strlen(input), streamOpt);
 
     tokenList tokens;
     parseStream(is, tokens);
@@ -261,7 +261,7 @@ Foam::ITstream::ITstream
 :
     ITstream(streamOpt, name)
 {
-    UIListStream is(input, streamOpt);
+    ISpanStream is(input, streamOpt);
 
     parseStream(is, static_cast<tokenList&>(*this));
     ITstream::seek(0);  // rewind(), but bypasss virtual
@@ -277,7 +277,7 @@ Foam::ITstream::ITstream
 :
     ITstream(streamOpt, name)
 {
-    UIListStream is(input.data(), input.length(), streamOpt);
+    ISpanStream is(input.data(), input.length(), streamOpt);
 
     parseStream(is, static_cast<tokenList&>(*this));
     ITstream::seek(0);  // rewind(), but bypasss virtual
@@ -293,7 +293,7 @@ Foam::ITstream::ITstream
 :
     ITstream(streamOpt, name)
 {
-    UIListStream is(input, strlen(input), streamOpt);
+    ISpanStream is(input, strlen(input), streamOpt);
 
     parseStream(is, static_cast<tokenList&>(*this));
     ITstream::seek(0);  // rewind(), but bypasss virtual

src/OpenFOAM/db/IOstreams/compat/IStringStream.H

@@ -4,8 +4,8 @@ Description
 
 \*---------------------------------------------------------------------------*/
 
-#ifndef IStringStream_H
-#define IStringStream_H
+#ifndef FoamCompat_IStringStream_H
+#define FoamCompat_IStringStream_H
 
 #include "StringStream.H"
 

src/OpenFOAM/db/IOstreams/compat/ListStream.H

@@ -0,0 +1,10 @@
+// Compatibility include.
+
+#ifndef FoamCompat_ListStream_H
+#define FoamCompat_ListStream_H
+
+#include "SpanStream.H"
+
+#endif
+
+// ************************************************************************* //

src/OpenFOAM/db/IOstreams/compat/OListStream.H

@@ -0,0 +1,10 @@
+// Compatibility include.
+
+#ifndef FoamCompat_OListStream_H
+#define FoamCompat_UListStream_H
+
+#include "SpanStream.H"
+
+#endif
+
+// ************************************************************************* //

src/OpenFOAM/db/IOstreams/compat/OStringStream.H

@@ -4,8 +4,8 @@ Description
 
 \*---------------------------------------------------------------------------*/
 
-#ifndef OStringStream_H
-#define OStringStream_H
+#ifndef FoamCompat_OStringStream_H
+#define FoamCompat_OStringStream_H
 
 #include "StringStream.H"
 

src/OpenFOAM/db/IOstreams/compat/UIListStream.H

@@ -0,0 +1,10 @@
+// Compatibility include.
+
+#ifndef FoamCompat_UIListStream_H
+#define FoamCompat_UIListStream_H
+
+#include "SpanStream.H"
+
+#endif
+
+// ************************************************************************* //

src/OpenFOAM/db/IOstreams/compat/UListStream.H

@@ -0,0 +1,10 @@
+// Compatibility include.
+
+#ifndef FoamCompat_UListStream_H
+#define FoamCompat_UListStream_H
+
+#include "SpanStream.H"
+
+#endif
+
+// ************************************************************************* //

src/OpenFOAM/db/IOstreams/compat/UOListStream.H

@@ -0,0 +1,10 @@
+// Compatibility include.
+
+#ifndef FoamCompat_UOListStream_H
+#define FoamCompat_UOListStream_H
+
+#include "SpanStream.H"
+
+#endif
+
+// ************************************************************************* //

src/OpenFOAM/db/IOstreams/hashes/OSHA1stream.H

@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011 OpenFOAM Foundation
-    Copyright (C) 2019-2022 OpenCFD Ltd.
+    Copyright (C) 2019-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -54,23 +54,21 @@ class osha1stream
     public std::ostream
 {
     //- A streambuf class for calculating SHA1 digests
-    class sha1buf
-    :
-        public std::streambuf
+    class sha1buf : public std::streambuf
     {
         //- This does all the work and has its own buffering
         SHA1 sha1_;
 
     protected:
 
-        //- Handle overflow
-        virtual int overflow(int c = EOF)
+        //- Output overflow handling - append to SHA1
+        virtual int overflow(int_type c = traits_type::eof())
         {
-            if (c != EOF) sha1_.append(c);
+            if (c != traits_type::eof()) sha1_.append(c);
             return c;
         }
 
-        //- Put sequence of characters
+        //- Put sequence of characters - append to SHA1
         virtual std::streamsize xsputn(const char* s, std::streamsize n)
         {
             if (n) sha1_.append(s, n);
@@ -83,10 +81,7 @@ class osha1stream
         sha1buf() = default;
 
         //- Full access to the sha1
-        SHA1& sha1() noexcept
-        {
-            return sha1_;
-        }
+        SHA1& sha1() noexcept { return sha1_; }
     };
 
 
@@ -100,25 +95,22 @@ public:
     // Constructors
 
         //- Default construct
-        osha1stream()
-        :
-            std::ostream(&buf_)
-        {}
+        osha1stream() : std::ostream(&buf_) {}
 
 
     // Member Functions
 
         //- This hides both signatures of std::basic_ios::rdbuf()
-        sha1buf* rdbuf()
-        {
-            return &buf_;
-        }
+        sha1buf* rdbuf() { return &buf_; }
 
         //- Full access to the sha1
-        SHA1& sha1() noexcept
-        {
-            return buf_.sha1();
-        }
+        SHA1& sha1() noexcept { return buf_.sha1(); }
+
+        //- Return SHA1::Digest for the data processed until now
+        SHA1Digest digest() { return buf_.sha1().digest(); }
+
+        //- Clear the SHA1 calculation
+        void reset() { buf_.sha1().clear(); }
 };
 
 
@@ -129,48 +121,21 @@ namespace Detail
                 Class Detail::OSHA1streamAllocator Declaration
 \*---------------------------------------------------------------------------*/
 
-//- Allocator for an osha1stream
+//- An allocator for holding Foam::osha1stream
 class OSHA1streamAllocator
 {
 protected:
 
     // Protected Data
 
-        typedef osha1stream stream_type;
-
         //- The output stream
-        stream_type stream_;
+        Foam::osha1stream stream_;
 
 
     // Constructors
 
         //- Default construct
         OSHA1streamAllocator() = default;
-
-
-public:
-
-    // Member Functions
-
-        //- Full access to the sha1
-        SHA1& sha1() noexcept
-        {
-            return stream_.sha1();
-        }
-
-
-        //- Return SHA1::Digest for the data processed until now
-        SHA1Digest digest()
-        {
-            return stream_.sha1().digest();
-        }
-
-
-        //- Clear the SHA1 calculation
-        void reset()
-        {
-            return stream_.sha1().clear();
-        }
 };
 
 } // End namespace Detail
@@ -188,16 +153,15 @@ class OSHA1stream
 {
     typedef Detail::OSHA1streamAllocator allocator_type;
 
-    // Private Member Functions
-
-        //- No copy construct
-        OSHA1stream(const OSHA1stream&) = delete;
-
-        //- No copy assignment
-        void operator=(const OSHA1stream&) = delete;
-
 public:
 
+    //- No copy construct
+    OSHA1stream(const OSHA1stream&) = delete;
+
+    //- No copy assignment
+    void operator=(const OSHA1stream&) = delete;
+
+
     // Constructors
 
         //- Construct with an empty digest
@@ -211,6 +175,18 @@ public:
         {}
 
 
+    // Member Functions
+
+        //- Full access to the sha1
+        SHA1& sha1() noexcept { return stream_.sha1(); }
+
+        //- Return SHA1::Digest for the data processed until now
+        SHA1Digest digest() { return stream_.digest(); }
+
+        //- Clear the SHA1 calculation
+        void reset() { stream_.reset(); }
+
+
     // Write Functions
 
         //- Add (unquoted) string contents.
@@ -227,7 +203,7 @@ public:
         //  \deprecated(2017-07) - use reset() method
         void rewind()
         {
-            sha1().clear();
+            stream_.sha1().clear();
         }
 
 

src/OpenFOAM/db/IOstreams/memory/ICharStream.H

@@ -0,0 +1,352 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | www.openfoam.com
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+    Copyright (C) 2017-2023 OpenCFD Ltd.
+-------------------------------------------------------------------------------
+License
+    This file is part of OpenFOAM.
+
+    OpenFOAM is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+    for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
+
+Class
+    Foam::ICharStream
+
+Description
+    An input stream that reads from a List and manages the List storage.
+    Similar to IStringStream but with a List for its storage instead of
+    as string to allow reuse of List contents without copying.
+
+See Also
+    Foam::OCharStream
+    Foam::ISpanStream
+    Foam::OSpanStream
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef Foam_ICharStream_H
+#define Foam_ICharStream_H
+
+#include "ISpanStream.H"
+#include "List.H"
+#include "DynamicList.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+
+// Forward Declarations
+class icharstream;
+class ICharStream;
+
+// Older names (prior to 2023-08)
+typedef ICharStream IListStream;
+
+
+/*---------------------------------------------------------------------------*\
+                        Class icharstream Declaration
+\*---------------------------------------------------------------------------*/
+
+//- Similar to std::istringstream, but with the ability to swap
+//- character content.
+//- Has some similarity to std::ispanstream (C++23)
+class icharstream
+:
+    virtual public std::ios,
+    protected Foam::memorybuf::in_dynamic,
+    public std::istream
+{
+    typedef Foam::memorybuf::in_dynamic buffer_type;
+    typedef std::istream stream_type;
+
+public:
+
+    // Constructors
+
+        //- Default construct - empty
+        icharstream()
+        :
+            buffer_type(),
+            stream_type(static_cast<buffer_type*>(this))
+        {}
+
+        //- Copy construct from content
+        icharstream(const char* buffer, size_t nbytes)
+        :
+            icharstream()
+        {
+            reset(buffer, nbytes);
+        }
+
+        // //- Construct (deep copy) from span character content
+        // explicit icharstream(stdFoam::span<char> s)
+        // :
+        //     icharstream()
+        // {
+        //     reset(buffer, nbytes);
+        // }
+
+        //- Move construct from List
+        icharstream(List<char>&& buffer)
+        :
+            icharstream()
+        {
+            swap(buffer);
+        }
+
+        //- Move construct from DynamicList
+        template<int SizeMin>
+        icharstream(DynamicList<char,SizeMin>&& buffer)
+        :
+            icharstream()
+        {
+            swap(buffer);
+        }
+
+
+    // Member Functions
+
+        //- The current get position within the buffer (tellg)
+        std::streampos input_pos() const
+        {
+            return buffer_type::span_tellg();
+        }
+
+        //- The get buffer capacity
+        std::streamsize capacity() const
+        {
+            return buffer_type::span_capacity();
+        }
+
+        //- The number of characters remaining in the get area.
+        //- Same as (capacity() - input_pos())
+        std::streamsize remaining() const
+        {
+            return buffer_type::span_remaining();
+        }
+
+        //- Span of the input characters (is modifiable!)
+        UList<char> list() const
+        {
+            return buffer_type::span_list();
+        }
+
+        //- Rewind the stream, clearing any old errors
+        void rewind()
+        {
+            buffer_type::pubseekpos(0, std::ios_base::in);
+            stream_type::clear();  // Clear old errors
+        }
+
+        //- Reset content (copy)
+        void reset(const char* buffer, size_t nbytes)
+        {
+            buffer_type::reset(buffer, nbytes);
+            stream_type::clear();  // Clear old errors
+        }
+
+        //- Transfer list contents to List buffer
+        void swap(List<char>& other)
+        {
+            buffer_type::swap(other);
+            stream_type::clear();  // Clear old errors
+        }
+
+        //- Transfer list contents to a DynamicList buffer
+        template<int SizeMin>
+        void swap(DynamicList<char,SizeMin>& other)
+        {
+            buffer_type::swap(other);
+            stream_type::clear();  // Clear old errors
+        }
+
+        //- Some information about the input buffer position/capacity
+        void debug_info(Ostream& os) const
+        {
+            os  << "get="
+                << input_pos() << '/' << capacity();
+        }
+};
+
+
+namespace Detail
+{
+
+/*---------------------------------------------------------------------------*\
+                Class Detail::ICharStreamAllocator Declaration
+\*---------------------------------------------------------------------------*/
+
+//- An allocator for holding Foam::icharstream
+class ICharStreamAllocator
+{
+protected:
+
+    // Protected Data
+
+        //- The stream
+        Foam::icharstream stream_;
+
+
+    // Constructors
+
+        //- Default construct
+        ICharStreamAllocator() = default;
+};
+
+} // End namespace Detail
+
+
+/*---------------------------------------------------------------------------*\
+                         Class ICharStream Declaration
+\*---------------------------------------------------------------------------*/
+
+//- An ISstream with internal List storage. Always UNCOMPRESSED.
+class ICharStream
+:
+    public Detail::ICharStreamAllocator,
+    public Foam::ISstream
+{
+    typedef Detail::ICharStreamAllocator allocator_type;
+
+public:
+
+    // Constructors
+
+        //- Default construct (empty), optionally with specified stream option
+        explicit ICharStream
+        (
+            IOstreamOption streamOpt = IOstreamOption()
+        )
+        :
+            allocator_type(),
+            ISstream(stream_, "input", streamOpt.format(), streamOpt.version())
+        {}
+
+        //- Copy construct from string content
+        explicit ICharStream
+        (
+            const std::string& buffer,
+            IOstreamOption streamOpt = IOstreamOption()
+        )
+        :
+            ICharStream(streamOpt)
+        {
+            stream_.reset(buffer.data(), buffer.size());
+        }
+
+        //- Move construct from List
+        explicit ICharStream
+        (
+            ::Foam::List<char>&& buffer,  // Fully qualify (issue #1521)
+            IOstreamOption streamOpt = IOstreamOption()
+        )
+        :
+            ICharStream(streamOpt)
+        {
+            stream_.swap(buffer);
+        }
+
+        //- Move construct from DynamicList (uses current size)
+        template<int SizeMin>
+        explicit ICharStream
+        (
+            DynamicList<char,SizeMin>&& buffer,
+            IOstreamOption streamOpt = IOstreamOption()
+        )
+        :
+            ICharStream(streamOpt)
+        {
+            stream_.swap(buffer);
+        }
+
+
+    // Member Functions
+
+        //- Position of the get buffer
+        std::streampos tellg() const { return stream_.input_pos(); }
+
+        //- The current get position within the buffer (tellg)
+        std::streampos input_pos() const { return stream_.input_pos(); }
+
+        //- The input list size. Same as capacity()
+        label size() const { return label(stream_.capacity()); }
+
+        //- The get buffer capacity
+        std::streamsize capacity() const { return stream_.capacity(); }
+
+        //- The number of characters remaining in the get area.
+        //- Same as (capacity() - input_pos())
+        std::streamsize remaining() const { return stream_.remaining(); }
+
+        //- Span of the input characters (is modifiable!)
+        UList<char> list() const { return stream_.list(); }
+
+        //- Rewind the stream, clearing any old errors
+        virtual void rewind()
+        {
+            stream_.rewind();
+            syncState();
+        }
+
+        //- Reset content (copy)
+        void reset(const char* buffer, size_t nbytes)
+        {
+            stream_.reset(buffer, nbytes);
+            syncState();
+        }
+
+        //- Transfer list contents to List buffer
+        void swap(List<char>& other)
+        {
+            stream_.swap(other);
+            syncState();
+        }
+
+        //- Transfer list contents to a DynamicList buffer
+        template<int SizeMin>
+        void swap(DynamicList<char,SizeMin>& other)
+        {
+            stream_.swap(other);
+            syncState();
+        }
+
+        //- Print stream description to Ostream
+        virtual void print(Ostream& os) const;
+
+
+    // Member Operators
+
+        //- A non-const reference to const Istream
+        //  Needed for read-constructors where the stream argument is temporary
+        Istream& operator()() const
+        {
+            // Could also rewind
+            return const_cast<ICharStream&>(*this);
+        }
+};
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //

src/OpenFOAM/db/IOstreams/memory/IListStream.H

@@ -1,261 +0,0 @@
-/*---------------------------------------------------------------------------*\
-  =========                 |
-  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
-   \\    /   O peration     |
-    \\  /    A nd           | www.openfoam.com
-     \\/     M anipulation  |
--------------------------------------------------------------------------------
-    Copyright (C) 2017-2022 OpenCFD Ltd.
--------------------------------------------------------------------------------
-License
-    This file is part of OpenFOAM.
-
-    OpenFOAM is free software: you can redistribute it and/or modify it
-    under the terms of the GNU General Public License as published by
-    the Free Software Foundation, either version 3 of the License, or
-    (at your option) any later version.
-
-    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
-    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
-    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
-    for more details.
-
-    You should have received a copy of the GNU General Public License
-    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
-
-Class
-    Foam::IListStream
-
-Description
-    An input stream that reads from a List and manages the List storage.
-    Similar to IStringStream but with a List for its storage instead of
-    as string to allow reuse of List contents without copying.
-
-See Also
-    Foam::OListStream
-    Foam::UIListStream
-    Foam::UOListStream
-
-\*---------------------------------------------------------------------------*/
-
-#ifndef Foam_IListStream_H
-#define Foam_IListStream_H
-
-#include "List.H"
-#include "UIListStream.H"
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-namespace Foam
-{
-namespace Detail
-{
-
-/*---------------------------------------------------------------------------*\
-                Class Detail::IListStreamAllocator Declaration
-\*---------------------------------------------------------------------------*/
-
-//- An stream/stream-buffer input allocator with List storage
-class IListStreamAllocator
-:
-    private List<char>,
-    public UIListStreamAllocator
-{
-protected:
-
-    // Constructors
-
-        //- Default construct
-        IListStreamAllocator()
-        :
-            List<char>(),
-            UIListStreamAllocator(List<char>::data(), List<char>::size())
-        {}
-
-        //- Move construct from List
-        IListStreamAllocator(List<char>&& buffer)
-        :
-            List<char>(std::move(buffer)),
-            UIListStreamAllocator(List<char>::data(), List<char>::size())
-        {}
-
-        //- Move construct from DynamicList
-        template<int SizeMin>
-        IListStreamAllocator(DynamicList<char,SizeMin>&& buffer)
-        :
-            List<char>(std::move(buffer)),
-            UIListStreamAllocator(List<char>::data(), List<char>::size())
-        {}
-
-
-    // Protected Member Functions
-
-        //- Convenience method to address the underlying List storage
-        inline void reset_gbuffer()
-        {
-            UIListStreamAllocator::reset
-            (
-                List<char>::data(),
-                List<char>::size()
-            );
-        }
-
-public:
-
-    // Member Functions
-
-        //- The current get position in the buffer
-        using UIListStreamAllocator::size;
-
-        //- Clear storage
-        inline void clearStorage()
-        {
-            List<char>::clear();
-            reset_gbuffer();
-        }
-
-        //- Transfer contents to other List
-        inline void swap(List<char>& list)
-        {
-            List<char>::swap(list);
-            reset_gbuffer();
-        }
-};
-
-} // End namespace Detail
-
-
-/*---------------------------------------------------------------------------*\
-                         Class IListStream Declaration
-\*---------------------------------------------------------------------------*/
-
-//- An ISstream with internal List storage. Always UNCOMPRESSED.
-class IListStream
-:
-    public Detail::IListStreamAllocator,
-    public ISstream
-{
-    typedef Detail::IListStreamAllocator allocator_type;
-
-public:
-
-    // Constructors
-
-        //- Default construct with an empty list
-        explicit IListStream
-        (
-            IOstreamOption streamOpt = IOstreamOption()
-        )
-        :
-            allocator_type(),
-            ISstream(stream_, "input", streamOpt.format(), streamOpt.version())
-        {}
-
-        //- Move construct from List
-        explicit IListStream
-        (
-            ::Foam::List<char>&& buffer,  // Fully qualify (issue #1521)
-            IOstreamOption streamOpt = IOstreamOption()
-        )
-        :
-            allocator_type(std::move(buffer)),
-            ISstream(stream_, "input", streamOpt.format(), streamOpt.version())
-        {}
-
-
-        //- Move construct from DynamicList
-        template<int SizeMin>
-        explicit IListStream
-        (
-            DynamicList<char,SizeMin>&& buffer,
-            IOstreamOption streamOpt = IOstreamOption()
-        )
-        :
-            allocator_type(std::move(buffer)),
-            ISstream(stream_, "input", streamOpt.format(), streamOpt.version())
-        {}
-
-
-    // Member Functions
-
-        //- The current get position in the buffer
-        using allocator_type::size;
-
-
-        //- Return the current get position in the buffer
-        std::streampos pos() const
-        {
-            return allocator_type::tellg();
-        }
-
-        //- Rewind the stream, clearing any old errors
-        virtual void rewind()
-        {
-            allocator_type::rewind();
-            setGood();  // resynchronize with internal state
-        }
-
-
-        //- Print stream description to Ostream
-        virtual void print(Ostream& os) const;
-
-
-    // Member Operators
-
-        //- A non-const reference to const Istream
-        //  Needed for read-constructors where the stream argument is temporary
-        Istream& operator()() const
-        {
-            // Could also rewind
-            return const_cast<IListStream&>(*this);
-        }
-
-
-    // Additional constructors and methods (as per v2012 and earlier)
-    #ifdef Foam_IOstream_extras
-
-        //- Construct with an empty list
-        explicit IListStream
-        (
-            IOstreamOption::streamFormat fmt
-        )
-        :
-            IListStream(IOstreamOption(fmt))
-        {}
-
-
-        //- Move construct from List
-        IListStream
-        (
-            ::Foam::List<char>&& buffer,  // Fully qualify (issue #1521)
-            IOstreamOption::streamFormat fmt
-        )
-        :
-            IListStream(std::move(buffer), IOstreamOption(fmt))
-        {}
-
-
-        //- Move construct from DynamicList
-        template<int SizeMin>
-        explicit IListStream
-        (
-            DynamicList<char,SizeMin>&& buffer,
-            IOstreamOption::streamFormat fmt
-        )
-        :
-            IListStream(std::move(buffer), IOstreamOption(fmt))
-        {}
-
-    #endif /* Foam_IOstream_extras */
-};
-
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-} // End namespace Foam
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-#endif
-
-// ************************************************************************* //

src/OpenFOAM/db/IOstreams/memory/ISpanStream.H

@@ -0,0 +1,352 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | www.openfoam.com
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+    Copyright (C) 2016-2023 OpenCFD Ltd.
+-------------------------------------------------------------------------------
+License
+    This file is part of OpenFOAM.
+
+    OpenFOAM is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+    for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
+
+Class
+    Foam::ISpanStream
+
+Description
+    Similar to IStringStream but using an externally managed buffer for its
+    input. This allows the input buffer to be filled (and refilled) from
+    various sources.
+
+    Note that this stream will normally be used as a "one-shot" reader.
+    Caution must be exercised that the referenced buffer remains valid and
+    without any intermediate resizing for the duration of the stream's use.
+
+    An example of possible use:
+    \code
+        DynamicList<char> buffer(4096);     // allocate some large buffer
+
+        nread = something.read(buffer.data(),1024); // fill with content
+        buffer.resize(nread);               // content size
+
+        // Construct dictionary, or something else
+        ISpanStream is(buffer)
+        dictionary dict1(is);
+
+        // Sometime later
+        nread = something.read(buffer.data(),2048); // fill with content
+        buffer.resize(nread);               // content size
+
+        // Without intermediate variable
+        dictionary dict2(ISpanStream(buffer)());
+    \endcode
+
+See Also
+    Foam::ICharStream
+    Foam::OCharStream
+    Foam::OSpanStream
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef Foam_ISpanStream_H
+#define Foam_ISpanStream_H
+
+#include "UList.H"
+#include "ISstream.H"
+#include "memoryStreamBuffer.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+
+// Forward Declarations
+class ispanstream;
+class ISpanStream;
+
+// Older names (prior to 2023-08)
+typedef ispanstream uiliststream;
+typedef ISpanStream UIListStream;
+
+
+/*---------------------------------------------------------------------------*\
+                         Class ispanstream Declaration
+\*---------------------------------------------------------------------------*/
+
+//- Similar to std::istringstream, but with an externally managed input buffer
+//- which makes it most similar to std::ispanstream (C++23)
+//  This allows the input buffer to be filled or refilled from various sources
+//  without copying.
+class ispanstream
+:
+    virtual public std::ios,
+    protected Foam::memorybuf::in_base,
+    public std::istream
+{
+    typedef Foam::memorybuf::in_base buffer_type;
+    typedef std::istream stream_type;
+
+public:
+
+    // Constructors
+
+        //- Default construct - empty
+        ispanstream()
+        :
+            buffer_type(),
+            stream_type(static_cast<buffer_type*>(this))
+        {}
+
+        //- Construct (shallow copy) for character array and number of bytes
+        ispanstream(const char* buffer, size_t nbytes)
+        :
+            buffer_type(const_cast<char*>(buffer), nbytes),
+            stream_type(static_cast<buffer_type*>(this))
+        {}
+
+        // //- Construct (shallow copy) from span character content
+        // ispanstream(stdFoam::span<char> s)
+        // :
+        //     buffer_type(const_cast<char*>(s.data()), s.size()),
+        //     stream_type(static_cast<buffer_type*>(this))
+        // {}
+
+
+    // Member Functions
+
+        //- The current get position within the buffer (tellg)
+        std::streampos input_pos() const
+        {
+            return buffer_type::span_tellg();
+        }
+
+        //- The get buffer capacity
+        std::streamsize capacity() const
+        {
+            return buffer_type::span_capacity();
+        }
+
+        //- The number of characters remaining in the get area.
+        //- Same as (capacity() - input_pos())
+        std::streamsize remaining() const
+        {
+            return buffer_type::span_remaining();
+        }
+
+        //- Span of the input characters (is modifiable!)
+        UList<char> list() const
+        {
+            return buffer_type::span_list();
+        }
+
+        //- Rewind the stream, clearing any old errors
+        void rewind()
+        {
+            buffer_type::pubseekpos(0, std::ios_base::in);
+            stream_type::clear();  // Clear old errors
+        }
+
+        //- Reset the get buffer area
+        void reset(const char* buffer, size_t nbytes)
+        {
+            buffer_type::resetg(const_cast<char*>(buffer), nbytes);
+            stream_type::clear();  // Clear old errors
+        }
+
+        //- Reset the get buffer area to use the data from a string
+        void reset(const std::string& s)
+        {
+            buffer_type::resetg(const_cast<char*>(&s[0]), s.size());
+            stream_type::clear();  // Clear old errors
+        }
+
+        //- Some information about the input buffer position/capacity
+        void debug_info(Ostream& os) const
+        {
+            os  << "get="
+                << input_pos() << '/' << capacity();
+        }
+};
+
+
+namespace Detail
+{
+
+/*---------------------------------------------------------------------------*\
+                Class Detail::ISpanStreamAllocator Declaration
+\*---------------------------------------------------------------------------*/
+
+//- An allocator for holding Foam::ispanstream
+class ISpanStreamAllocator
+{
+protected:
+
+    // Protected Data
+
+        //- The stream
+        Foam::ispanstream stream_;
+
+
+    // Constructors
+
+        //- Default construct (empty)
+        ISpanStreamAllocator() = default;
+};
+
+} // End namespace Detail
+
+
+/*---------------------------------------------------------------------------*\
+                         Class ISpanStream Declaration
+\*---------------------------------------------------------------------------*/
+
+class ISpanStream
+:
+    public Detail::ISpanStreamAllocator,
+    public Foam::ISstream
+{
+    typedef Detail::ISpanStreamAllocator allocator_type;
+
+public:
+
+    // Constructors
+
+        //- Default construct (empty), optionally with specified stream option
+        explicit ISpanStream
+        (
+            IOstreamOption streamOpt = IOstreamOption()
+        )
+        :
+            allocator_type(),
+            ISstream(stream_, "input", streamOpt.format(), streamOpt.version())
+        {}
+
+        //- Construct using specified buffer and number of bytes
+        ISpanStream
+        (
+            const char* buffer,
+            size_t nbytes,
+            IOstreamOption streamOpt = IOstreamOption()
+        )
+        :
+            ISpanStream(streamOpt)
+        {
+            reset(buffer, nbytes);
+        }
+
+        //- Use data area from string content
+        explicit ISpanStream
+        (
+            const std::string& buffer,
+            IOstreamOption streamOpt = IOstreamOption()
+        )
+        :
+            ISpanStream(streamOpt)
+        {
+            reset(buffer);
+        }
+
+        //- Construct using data area from a List and number of bytes
+        ISpanStream
+        (
+            const ::Foam::UList<char>& buffer,
+            size_t nbytes,
+            IOstreamOption streamOpt = IOstreamOption()
+        )
+        :
+            ISpanStream(buffer.cdata(), nbytes, streamOpt)
+        {}
+
+        //- Construct using data area from a List and its inherent storage size
+        //  Uses addressed size, thus no special treatment for a DynamicList
+        explicit ISpanStream
+        (
+            const ::Foam::UList<char>& buffer,
+            IOstreamOption streamOpt = IOstreamOption()
+        )
+        :
+            ISpanStream(buffer.cdata(), buffer.size(), streamOpt)
+        {}
+
+
+    // Member Functions
+
+        //- Position of the get buffer
+        std::streampos tellg() const { return stream_.input_pos(); }
+
+        //- The current get position within the buffer (tellg)
+        std::streampos input_pos() const { return stream_.input_pos(); }
+
+        //- The input list size. Same as capacity()
+        label size() const { return label(stream_.capacity()); }
+
+        //- The get buffer capacity
+        std::streamsize capacity() const { return stream_.capacity(); }
+
+        //- The number of characters remaining in the get area.
+        //- Same as (capacity() - input_pos())
+        std::streamsize remaining() const { return stream_.remaining(); }
+
+
+        //- Span of the current input characters (is modifiable!)
+        UList<char> list() const { return stream_.list(); }
+
+        //- Reset input area, position to buffer start and clear errors
+        void reset(const char* buffer, size_t nbytes)
+        {
+            stream_.reset(buffer, nbytes);
+            syncState();
+        }
+
+        //- Reset input area to use data from a string
+        void reset(const std::string& s)
+        {
+            stream_.reset(s);
+            syncState();
+        }
+
+        //- Rewind the stream, clearing any old errors
+        virtual void rewind()
+        {
+            stream_.rewind();
+            syncState();
+        }
+
+        //- Print stream description to Ostream
+        virtual void print(Ostream& os) const;
+
+
+    // Member Operators
+
+        //- A non-const reference to const Istream
+        //  Needed for read-constructors where the stream argument is temporary
+        Istream& operator()() const
+        {
+            // Could also rewind
+            return const_cast<ISpanStream&>(*this);
+        }
+};
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //

src/OpenFOAM/db/IOstreams/memory/OCharStream.H

@@ -0,0 +1,316 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | www.openfoam.com
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+    Copyright (C) 2017-2023 OpenCFD Ltd.
+-------------------------------------------------------------------------------
+License
+    This file is part of OpenFOAM.
+
+    OpenFOAM is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+    for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
+
+Class
+    Foam::OCharStream
+
+Description
+    An output stream that writes to a List and manages the List storage.
+    Similar to OStringStream but with a List for its storage instead of
+    as string to allow reuse of List contents without copying.
+
+    The default initial size is 512-bytes and uses size doubling.
+    After construction can use the reserve() method to adjust this.
+
+See Also
+    Foam::ICharStream
+    Foam::OSpanStream
+    Foam::ISpanStream
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef Foam_OCharStream_H
+#define Foam_OCharStream_H
+
+#include "OSpanStream.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+
+// Forward Declarations
+class ocharstream;
+class OCharStream;
+
+// Older names (prior to 2023-08)
+typedef OCharStream OListStream;
+
+
+/*---------------------------------------------------------------------------*\
+                        Class ocharstream Declaration
+\*---------------------------------------------------------------------------*/
+
+//- Similar to std::ostringstream, but with the ability to swap
+//- character content.
+//- Has some similarity to std::ospanstream (C++23)
+class ocharstream
+:
+    virtual public std::ios,
+    protected Foam::memorybuf::out_dynamic,
+    public std::ostream
+{
+    typedef Foam::memorybuf::out_dynamic buffer_type;
+    typedef std::ostream stream_type;
+
+public:
+
+    // Constructors
+
+        //- Default construct - empty
+        ocharstream()
+        :
+            buffer_type(),
+            stream_type(static_cast<buffer_type*>(this))
+        {}
+
+        //- Move construct from List
+        ocharstream(List<char>&& buffer)
+        :
+            ocharstream()
+        {
+            swap(buffer);
+        }
+
+        //- Move construct from DynamicList
+        template<int SizeMin>
+        ocharstream(DynamicList<char,SizeMin>&& buffer)
+        :
+            ocharstream()
+        {
+            swap(buffer);
+        }
+
+
+    // Member Functions
+
+        //- The current output position within the buffer (tellp)
+        std::streampos output_pos() const
+        {
+            return (buffer_type::span_tellp());
+        }
+
+        //- The put buffer capacity
+        std::streamsize capacity() const
+        {
+            return buffer_type::span_capacity();
+        }
+
+        //- Reserve output space for at least this amount
+        void reserve(const std::streamsize n)
+        {
+            buffer_type::reserve(n);
+        }
+
+        //- Span of the current output characters (is modifiable!)
+        UList<char> list() const
+        {
+            return buffer_type::span_list();
+        }
+
+        //- Rewind the stream, clearing any old errors
+        void rewind()
+        {
+            buffer_type::pubseekpos(0, std::ios_base::out);
+            stream_type::clear();  // Clear old errors
+        }
+
+        //- Transfer list contents to List buffer
+        void swap(List<char>& other)
+        {
+            buffer_type::swap(other);
+            stream_type::clear();  // Clear old errors
+        }
+
+        //- Transfer list contents to a DynamicList buffer
+        template<int SizeMin>
+        void swap(DynamicList<char,SizeMin>& other)
+        {
+            buffer_type::swap(other);
+            stream_type::clear();  // Clear old errors
+        }
+
+        //- Some information about the output buffer position/capacity
+        void debug_info(Ostream& os) const
+        {
+            os  << "put="
+                << output_pos() << '/' << capacity();
+        }
+};
+
+
+namespace Detail
+{
+
+/*---------------------------------------------------------------------------*\
+                Class Detail::OCharStreamAllocator Declaration
+\*---------------------------------------------------------------------------*/
+
+//- An allocator for holding Foam::ocharstream
+class OCharStreamAllocator
+{
+protected:
+
+    // Protected Data
+
+        //- The stream
+        Foam::ocharstream stream_;
+
+
+    // Constructors
+
+        //- Default construct - empty
+        OCharStreamAllocator() = default;
+};
+
+} // End namespace Detail
+
+
+/*---------------------------------------------------------------------------*\
+                         Class OCharStream Declaration
+\*---------------------------------------------------------------------------*/
+
+//- An OSstream with internal List storage
+class OCharStream
+:
+    public Detail::OCharStreamAllocator,
+    public Foam::OSstream
+{
+    typedef Detail::OCharStreamAllocator allocator_type;
+
+public:
+
+    // Constructors
+
+        //- Default construct (empty output)
+        explicit OCharStream
+        (
+            IOstreamOption streamOpt = IOstreamOption()
+        )
+        :
+            allocator_type(),
+            OSstream(stream_, "output", streamOpt.format(), streamOpt.version())
+        {}
+
+        //- Construct with initial reserved number of bytes
+        explicit OCharStream
+        (
+            size_t nbytes,
+            IOstreamOption streamOpt = IOstreamOption()
+        )
+        :
+            OCharStream(streamOpt)
+        {
+            stream_.reserve(nbytes);
+        }
+
+        //- Move construct from a List
+        explicit OCharStream
+        (
+            ::Foam::List<char>&& buffer,
+            IOstreamOption streamOpt = IOstreamOption()
+        )
+        :
+            OCharStream(streamOpt)
+        {
+            stream_.swap(buffer);
+        }
+
+        //- Move construct from a DynamicList (uses entire capacity)
+        template<int SizeMin>
+        explicit OCharStream
+        (
+            ::Foam::DynamicList<char,SizeMin>&& buffer,
+            IOstreamOption streamOpt = IOstreamOption()
+        )
+        :
+            OCharStream(streamOpt)
+        {
+            stream_.swap(buffer);
+        }
+
+
+    // Member Functions
+
+        //- Position of the put buffer
+        std::streampos tellp() const { return stream_.output_pos(); }
+
+        //- The current output position within the buffer (tellp)
+        std::streampos output_pos() const { return stream_.output_pos(); }
+
+        //- The current output size. Same as tellp(), output_pos()
+        label size() const { return label(stream_.output_pos()); }
+
+        //- The put buffer capacity
+        std::streamsize capacity() const { return stream_.capacity(); }
+
+        //- Reserve output space for at least this amount
+        void reserve(const std::streamsize n) { stream_.reserve(n); }
+
+        //- Span of the current output characters (is modifiable!)
+        UList<char> list() const { return stream_.list(); }
+
+        //- Rewind the stream, clearing any old errors
+        virtual void rewind()
+        {
+            stream_.rewind();
+            syncState();
+        }
+
+        //- Transfer list contents to List buffer
+        void swap(List<char>& other)
+        {
+            stream_.swap(other);
+            syncState();
+        }
+
+        //- Transfer list contents to a DynamicList buffer
+        template<int SizeMin>
+        void swap(DynamicList<char,SizeMin>& other)
+        {
+            stream_.swap(other);
+            syncState();
+        }
+
+        //- Print stream description to Ostream
+        virtual void print(Ostream& os) const;
+
+
+    // Houskeeping
+
+        //- Block size was used in OpenFOAM-v2306 and earlier
+        void setBlockSize(int n) {}
+};
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //

src/OpenFOAM/db/IOstreams/memory/OCountStream.H

@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2016-2021 OpenCFD Ltd.
+    Copyright (C) 2016-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -42,103 +42,6 @@ Description
 namespace Foam
 {
 
-/*---------------------------------------------------------------------------*\
-                       Class countstreambuf Declaration
-\*---------------------------------------------------------------------------*/
-
-//- A streambuf class for determining byte counts
-class countstreambuf
-:
-    public std::streambuf
-{
-    //- The number of bytes counted
-    std::streamsize size_;
-
-protected:
-
-    //- Set position pointer to relative position
-    virtual std::streampos seekoff
-    (
-        std::streamoff off,
-        std::ios_base::seekdir way,
-        std::ios_base::openmode which = std::ios_base::in|std::ios_base::out
-    )
-    {
-        if (which & std::ios_base::out)
-        {
-            if (way == std::ios_base::beg)
-            {
-                size_ = off;
-            }
-            else if (way == std::ios_base::cur)
-            {
-                size_ += off;
-            }
-            else if (way == std::ios_base::end)
-            {
-                // not really possible
-            }
-
-            return size_; // tellp()
-        }
-
-        return -1;
-    }
-
-
-    //- Set position pointer to absolute position
-    //  For the counter, adjust the count accordingly.
-    virtual std::streampos seekpos
-    (
-        std::streampos pos,
-        std::ios_base::openmode which = std::ios_base::in|std::ios_base::out
-    )
-    {
-        return seekoff(pos, std::ios_base::beg, which);
-    }
-
-
-    //- Handle output counting via overflow
-    virtual int overflow(int c = EOF)
-    {
-        if (c != EOF)
-        {
-            ++size_;
-        }
-        return c;
-    }
-
-
-    //- Put sequence of characters
-    virtual std::streamsize xsputn(const char* s, std::streamsize n)
-    {
-        size_ += n;
-        return n;
-    }
-
-
-public:
-
-    //- Default construct, or with precount size
-    explicit countstreambuf(std::streamsize precount=0)
-    :
-        size_(precount)
-    {}
-
-    //- \return The buffer put position == number of bytes counted.
-    std::streamsize tellp() const
-    {
-        return size_;
-    }
-
-    //- Some information about the number of bytes counted
-    void printBufInfo(Ostream& os) const
-    {
-        os << "count=" << size_;
-    }
-};
-
-
 /*---------------------------------------------------------------------------*\
                         Class ocountstream Declaration
 \*---------------------------------------------------------------------------*/
@@ -149,34 +52,124 @@ public:
 class ocountstream
 :
     virtual public std::ios,
-    protected countstreambuf,
     public std::ostream
 {
+    //- A streambuf class for determining byte counts
+    class countbuf : public std::streambuf
+    {
+        //- The number of bytes counted
+        std::streamsize size_;
+
+    protected:
+
+        //- Set position pointer to relative position
+        virtual std::streampos seekoff
+        (
+            std::streamoff off,
+            std::ios_base::seekdir way,
+            std::ios_base::openmode which = std::ios_base::in|std::ios_base::out
+        )
+        {
+            if (which & std::ios_base::out)
+            {
+                if (way == std::ios_base::beg)
+                {
+                    size_ = off;
+                }
+                else if (way == std::ios_base::cur)
+                {
+                    size_ += off;
+                }
+                else if (way == std::ios_base::end)
+                {
+                    // not really possible
+                }
+
+                return size_;  // Like span_tellp()
+            }
+
+            return -1;
+        }
+
+        //- Set position pointer to absolute position
+        //  For the counter, adjust the count accordingly.
+        virtual std::streampos seekpos
+        (
+            std::streampos pos,
+            std::ios_base::openmode which = std::ios_base::in|std::ios_base::out
+        )
+        {
+            return seekoff(pos, std::ios_base::beg, which);
+        }
+
+        //- Output overflow handling - increment counter
+        virtual int overflow(int_type c = traits_type::eof())
+        {
+            if (c != traits_type::eof()) ++size_;
+            return c;
+        }
+
+        //- Put sequence of characters - increment counter
+        virtual std::streamsize xsputn(const char* s, std::streamsize n)
+        {
+            size_ += n;
+            return n;
+        }
+
+    public:
+
+        // Constructors
+
+            //- Default construct, count = 0
+            countbuf() : size_(0) {}
+
+
+        // Member Functions
+
+            //- The number of bytes counted.
+            std::streamsize count() const noexcept { return size_; }
+
+            //- Reset the count
+            void reset(std::streamsize n = 0) noexcept { size_ = n; }
+    };
+
+
+    // Private Data
+
+        typedef countbuf buffer_type;
+        typedef std::ostream stream_type;
+
+        //- Reference to the underlying buffer
+        buffer_type buf_;
+
 public:
 
-    //- Default construct
-    ocountstream()
-    :
-        countstreambuf(),
-        std::ostream(static_cast<countstreambuf*>(this))
-    {}
+    // Constructors
+
+        //- Default construct
+        ocountstream() : stream_type(&buf_) {}
 
 
-    //- \return The buffer put position == number of bytes counted.
-    using countstreambuf::tellp;
+    // Member Functions
 
-    //- \return The number of bytes counted
-    std::streamsize size() const
-    {
-        return countstreambuf::tellp();
-    }
+        //- This hides both signatures of std::basic_ios::rdbuf()
+        countbuf* rdbuf() { return &buf_; }
 
-    //- Rewind the stream, reset the count
-    void rewind()
-    {
-        this->pubseekpos(0, std::ios_base::out);
-        clear(); // for safety, clear any old errors
-    }
+        //- \return The number of bytes counted
+        std::streamsize count() const noexcept { return buf_.count(); }
+
+        //- Reset the count
+        void reset(std::streamsize n = 0) noexcept
+        {
+            buf_.reset(n);
+            stream_type::clear();  // Clear old errors
+        }
+
+        //- Some information about the output buffer position/capacity
+        void debug_info(Ostream& os) const
+        {
+            os  << "count=" << buf_.count();
+        }
 };
 
 
@@ -187,55 +180,21 @@ namespace Detail
                 Class Detail::OCountStreamAllocator Declaration
 \*---------------------------------------------------------------------------*/
 
-//- An stream/stream-buffer allocator for counting
+//- An allocator for holding Foam::ocountstream
 class OCountStreamAllocator
 {
 protected:
 
     // Protected Data
 
-        typedef std::ostream stream_type;
-
-        //- The stream buffer
-        countstreambuf buf_;
-
         //- The output stream
-        stream_type stream_;
+        Foam::ocountstream stream_;
 
 
     // Constructors
 
-        //- Default construct, or with precount size
-        OCountStreamAllocator(std::streamsize precount=0)
-        :
-            buf_(precount),
-            stream_(&buf_)
-        {}
-
-
-    // Protected Member Functions
-
-        void printBufInfo(Ostream& os) const
-        {
-            buf_.printBufInfo(os);
-        }
-
-public:
-
-    // Member Functions
-
-        //- The number of bytes counted
-        std::streamsize size() const
-        {
-            return buf_.tellp();
-        }
-
-        //- Rewind the stream, reset the count
-        void rewind()
-        {
-            buf_.pubseekpos(0);
-            stream_.clear(); // for safety, clear any old errors
-        }
+        //- Default construct
+        OCountStreamAllocator() = default;
 };
 
 } // End namespace Detail
@@ -270,35 +229,33 @@ public:
         //- Copy construct
         OCountStream(const OCountStream& str)
         :
-            allocator_type(str.size()),
+            allocator_type(),
             OSstream(stream_, str.name(), static_cast<IOstreamOption>(str))
-        {}
+        {
+            stream_.reset(str.count());
+        }
 
 
     // Member Functions
 
+        //- \return The number of bytes counted
+        std::streamsize count() const noexcept { return stream_.count(); }
+
+        //- \return The number of bytes counted
+        std::streamsize size() const noexcept { return stream_.count(); }
+
+        //- Reset the count
+        void reset(std::streamsize n = 0) noexcept { stream_.reset(n); }
+
         //- Rewind the stream, reset the count, clearing any old errors
         virtual void rewind()
         {
-            allocator_type::rewind();
-            setGood();  // resynchronize with internal state
+            stream_.reset();
+            syncState();
         }
 
         //- Print stream description to Ostream
         virtual void print(Ostream& os) const;
-
-
-    // Additional constructors and methods (as per v2012 and earlier)
-    #ifdef Foam_IOstream_extras
-
-        //- Construct empty with format
-        explicit OCountStream(IOstreamOption::streamFormat fmt)
-        :
-            OCountStream(IOstreamOption(fmt))
-        {}
-
-
-    #endif /* Foam_IOstream_extras */
 };
 
 

src/OpenFOAM/db/IOstreams/memory/OListStream.H

@@ -1,522 +0,0 @@
-/*---------------------------------------------------------------------------*\
-  =========                 |
-  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
-   \\    /   O peration     |
-    \\  /    A nd           | www.openfoam.com
-     \\/     M anipulation  |
--------------------------------------------------------------------------------
-    Copyright (C) 2017-2022 OpenCFD Ltd.
--------------------------------------------------------------------------------
-License
-    This file is part of OpenFOAM.
-
-    OpenFOAM is free software: you can redistribute it and/or modify it
-    under the terms of the GNU General Public License as published by
-    the Free Software Foundation, either version 3 of the License, or
-    (at your option) any later version.
-
-    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
-    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
-    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
-    for more details.
-
-    You should have received a copy of the GNU General Public License
-    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
-
-Class
-    Foam::OListStream
-
-Description
-    An output stream that writes to a List and manages the List storage.
-    Similar to OStringStream but with a List for its storage instead of
-    as string to allow reuse of List contents without copying.
-
-    The default list size is 512-bytes with a 256-byte block increment.
-    These values can be changed after construction using the reserve() and
-    the setBlockSize() methods.
-
-See Also
-    Foam::IListStream
-    Foam::UOListStream
-    Foam::UIListStream
-
-\*---------------------------------------------------------------------------*/
-
-#ifndef Foam_OListStream_H
-#define Foam_OListStream_H
-
-#include "DynamicList.H"
-#include "OSstream.H"
-#include "memoryStreamBuffer.H"
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-namespace Foam
-{
-
-namespace Detail
-{
-
-/*---------------------------------------------------------------------------*\
-                Class Detail::OListStreamAllocator Declaration
-\*---------------------------------------------------------------------------*/
-
-//- An stream/stream-buffer output allocator with DynamicList-like storage
-class OListStreamAllocator
-{
-    //- A streambuf adapter with resizing similar to DynamicList
-    class dynbuf
-    :
-        public memorybuf::out
-    {
-        friend class OListStreamAllocator;
-
-        //- Helper for block size - small list minimum of 64 bytes.
-        constexpr static int min_size(int n)
-        {
-            return stdFoam::max(64, n);
-        }
-
-        //- Block size when resizing the list
-        int block_ = 256;
-
-        //- Underlying list storage.
-        //  Internally manage like a DynamicList, with its capacity known
-        //  from the list size and the addressable size known through the
-        //  stream pointers.
-        List<char> storage_;
-
-
-    protected:
-
-        //- Increment capacity directly and adjust buffer pointers to
-        //- correspond with the storage size.
-        inline void minCapacity
-        (
-            const std::streamsize n,
-            const std::streamsize cur = 0
-        )
-        {
-            const auto newEnd = n + cur;
-            if (newEnd > storage_.size())
-            {
-                auto newCapacity =
-                (
-                    (storage_.size() + block_)
-                  - (storage_.size() % block_)
-                );
-
-                while (newCapacity < newEnd)
-                {
-                    newCapacity += block_;
-                }
-
-                // Info<<"request:" << newEnd
-                //     << " cur cap:" << storage_.size()
-                //     << " new cap:" << newCapacity
-                //     << " pos:" << cur
-                //     << " incr:" << incr << endl;
-
-                storage_.resize(newCapacity);
-                sync_pbuffer();
-                pbump(cur);
-            }
-        }
-
-        //- Define new increment
-        inline void setBlockSize(const int i)
-        {
-            const auto prev = block_;
-            block_ = min_size(i);
-
-            if (block_ > prev)
-            {
-                minCapacity(0, tellp());
-            }
-        }
-
-        //- Handle overflow
-        virtual int overflow(int c = EOF)
-        {
-            if (c != EOF)
-            {
-                // Need another output block
-                minCapacity(block_, tellp());
-
-                *(pptr()) = c;
-                pbump(1);
-            }
-            return c;
-        }
-
-
-        //- Put sequence of characters
-        virtual std::streamsize xsputn(const char* s, std::streamsize n)
-        {
-            // Enough space so that appends work without problem
-            minCapacity(n, tellp());
-
-            std::streamsize count = 0;
-            while (count < n && pptr() < epptr())
-            {
-                *(pptr()) = *(s + count++);
-                pbump(1);
-            }
-
-            return count;
-        }
-
-        //- Initialize put buffer
-        void init_pbuffer(const std::streamsize n)
-        {
-            sync_pbuffer();
-            minCapacity(n);
-        }
-
-
-    public:
-
-    // Constructors
-
-        //- Default construct, with initial reserved number of bytes
-        dynbuf(size_t nbytes = 512)
-        :
-            storage_()
-        {
-            init_pbuffer(min_size(nbytes));
-        }
-
-        //- Move construct from List
-        dynbuf(List<char>&& buffer)
-        :
-            storage_(std::move(buffer))
-        {
-            init_pbuffer(block_);
-        }
-
-        //- Move construct from DynamicList.
-        template<int SizeMin>
-        dynbuf(DynamicList<char,SizeMin>&& buffer)
-        :
-            storage_(std::move(buffer))
-        {
-            init_pbuffer(block_);
-        }
-
-
-    // Member Functions
-
-        //- Return the current list output capacity
-        inline label capacity() const
-        {
-            return storage_.size();
-        }
-
-        //- Sync put buffer pointers to agree with list dimensions
-        //  Sets put pointer to the begin (rewind).
-        inline void sync_pbuffer()
-        {
-            resetp(storage_.data(), storage_.size());
-        }
-
-        //- Clear storage
-        inline void clearStorage()
-        {
-            storage_.clear();
-            sync_pbuffer();
-        }
-
-        //- Shrink storage to addressed storage
-        inline void shrink()
-        {
-            const auto cur = tellp();   // Addressed area
-
-            storage_.resize(cur);
-            sync_pbuffer();
-            pbump(cur);
-        }
-
-        //- Transfer list contents to other List
-        inline void swap(List<char>& other)
-        {
-            const auto cur = tellp();   // Addressed area
-
-            storage_.swap(other);
-            storage_.resize(cur);
-            sync_pbuffer();
-        }
-
-        //- Transfer list contents to a DynamicList
-        template<int SizeMin>
-        inline void swap(DynamicList<char,SizeMin>& other)
-        {
-            const auto cur = tellp();   // Addressed area
-
-            storage_.swap(other);       // Swap full list
-            other.setCapacity(other.size());
-            other.resize(cur);
-            sync_pbuffer();
-        }
-    };
-
-
-protected:
-
-    // Protected Data
-
-        typedef std::ostream stream_type;
-
-        //- The stream buffer
-        dynbuf buf_;
-
-        //- The stream
-        stream_type stream_;
-
-
-    // Constructors
-
-        //- Default construct, with initial reserved number of bytes
-        OListStreamAllocator(size_t nbytes = 512)
-        :
-            buf_(nbytes),
-            stream_(&buf_)
-        {}
-
-        //- Move construct from List
-        OListStreamAllocator(List<char>&& buffer)
-        :
-            buf_(std::move(buffer)),
-            stream_(&buf_)
-        {}
-
-        //- Move construct from DynamicList
-        template<int SizeMin>
-        OListStreamAllocator(DynamicList<char,SizeMin>&& buffer)
-        :
-            buf_(std::move(buffer)),
-            stream_(&buf_)
-        {}
-
-
-    // Protected Member Functions
-
-        void printBufInfo(Ostream& os) const
-        {
-            os  << "put=" << buf_.tellp()
-                << "/" << buf_.capacity()
-                << " block=" << buf_.block_;
-        }
-
-public:
-
-    // Member Functions
-
-        //- Const UList access to the characters written (shallow copy).
-        inline const UList<char> list() const
-        {
-            return buf_.list();
-        }
-
-        //- Non-const UList access to the characters written (shallow copy).
-        inline UList<char> list()
-        {
-            return buf_.list();
-        }
-
-        //- The current list output capacity
-        inline label capacity() const
-        {
-            return buf_.capacity();
-        }
-
-        //- The current output position in the buffer,
-        //- which is also the addressed list size
-        inline label size() const
-        {
-            return buf_.tellp();
-        }
-
-        //- Reserve output space for at least this amount.
-        inline void reserve(const std::streamsize n)
-        {
-            // Also maintain current position when resizing
-            const auto cur = buf_.tellp();
-            if (n > cur)
-            {
-                buf_.minCapacity(n - cur, cur);
-            }
-        }
-
-        //- Adjust block size for output
-        inline void setBlockSize(int n)
-        {
-            return buf_.setBlockSize(n);
-        }
-
-        //- Transfer list contents to other List
-        inline void swap(List<char>& other)
-        {
-            buf_.swap(other);
-        }
-
-        //- Transfer list contents to a DynamicList
-        template<int SizeMin>
-        inline void swap(DynamicList<char,SizeMin>& other)
-        {
-            buf_.swap(other);
-        }
-
-        //- Shrink to addressed space, should not affect stream.
-        inline void shrink()
-        {
-            buf_.shrink();
-        }
-
-        //- Clear storage
-        void clearStorage()
-        {
-            buf_.clearStorage();
-            stream_.clear(); // for safety, clear any old errors
-        }
-
-        //- Move to buffer start, clear errors
-        void rewind()
-        {
-            buf_.pubseekpos(0, std::ios_base::out);
-            stream_.clear(); // for safety, clear any old errors
-        }
-};
-
-} // End namespace Detail
-
-
-/*---------------------------------------------------------------------------*\
-                         Class OListStream Declaration
-\*---------------------------------------------------------------------------*/
-
-//- An OSstream attached to a List
-class OListStream
-:
-    public Detail::OListStreamAllocator,
-    public OSstream
-{
-    typedef Detail::OListStreamAllocator allocator_type;
-
-public:
-
-    // Constructors
-
-        //- Default construct (empty output)
-        explicit OListStream
-        (
-            IOstreamOption streamOpt = IOstreamOption()
-        )
-        :
-            allocator_type(),
-            OSstream(stream_, "output", streamOpt.format(), streamOpt.version())
-        {}
-
-        //- Construct with initial reserved number of bytes
-        explicit OListStream
-        (
-            size_t nbytes,
-            IOstreamOption streamOpt = IOstreamOption()
-        )
-        :
-            allocator_type(nbytes),
-            OSstream(stream_, "output", streamOpt.format(), streamOpt.version())
-        {}
-
-        //- Move construct from an existing List
-        explicit OListStream
-        (
-            List<char>&& buffer,
-            IOstreamOption streamOpt = IOstreamOption()
-        )
-        :
-            allocator_type(std::move(buffer)),
-            OSstream(stream_, "output", streamOpt.format(), streamOpt.version())
-        {}
-
-        //- Move construct from an existing DynamicList
-        template<int SizeMin>
-        explicit OListStream
-        (
-            DynamicList<char,SizeMin>&& buffer,
-            IOstreamOption streamOpt = IOstreamOption()
-        )
-        :
-            allocator_type(std::move(buffer)),
-            OSstream(stream_, "output", streamOpt.format(), streamOpt.version())
-        {}
-
-
-    // Member Functions
-
-        //- Rewind the stream, clearing any old errors
-        virtual void rewind()
-        {
-            allocator_type::rewind();
-            setGood();  // resynchronize with internal state
-        }
-
-        //- Print stream description to Ostream
-        virtual void print(Ostream& os) const;
-
-
-    // Additional constructors and methods (as per v2012 and earlier)
-    #ifdef Foam_IOstream_extras
-
-        //- Default construct (empty output)
-        explicit OListStream
-        (
-            IOstreamOption::streamFormat fmt
-        )
-        :
-            OListStream(IOstreamOption(fmt))
-        {}
-
-        //- Construct with initial reserved number of bytes
-        explicit OListStream
-        (
-            size_t nbytes,
-            IOstreamOption::streamFormat fmt
-        )
-        :
-            OListStream(nbytes, IOstreamOption(fmt))
-        {}
-
-        //- Move construct from an existing List
-        OListStream
-        (
-            List<char>&& buffer,
-            IOstreamOption::streamFormat fmt
-        )
-        :
-            OListStream(std::move(buffer), IOstreamOption(fmt))
-        {}
-
-        //- Move construct from an existing DynamicList
-        template<int SizeMin>
-        OListStream
-        (
-            DynamicList<char,SizeMin>&& buffer,
-            IOstreamOption::streamFormat fmt
-        )
-        :
-            OListStream(std::move(buffer), IOstreamOption(fmt))
-        {}
-
-    #endif /* Foam_IOstream_extras */
-};
-
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-} // End namespace Foam
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-#endif
-
-// ************************************************************************* //

src/OpenFOAM/db/IOstreams/memory/OSpanStream.H

@@ -0,0 +1,358 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | www.openfoam.com
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+    Copyright (C) 2016-2023 OpenCFD Ltd.
+-------------------------------------------------------------------------------
+License
+    This file is part of OpenFOAM.
+
+    OpenFOAM is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+    for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
+
+Class
+    Foam::OSpanStream
+
+Description
+    Similar to OStringStream but using an externally managed buffer for
+    its output.
+
+    This allows the output buffer to be reused and can make it easier when
+    writing out data.  It is the user's responsibility to ensure proper
+    synchronization in the sizes. Provided that the external buffer is large
+    enough that overflow does not occur, the following usage pattern
+    works.
+
+    \code
+        DynamicList<char> buffer(4096);     // allocate some large buffer
+
+        {
+            OSpanStream os(buffer);
+            os << "content1" << " and more content";
+            buffer.resize(os.size());       // synchronize sizes
+        }
+
+        something.write(buffer, buffer.size());
+    \endcode
+
+    Although the OSpanStream is quite lightweight, there may be cases
+    where it is preferable to reuse the stream as well.
+    \code
+        DynamicList<char> buffer(4096);     // allocate some large buffer
+
+        OSpanStream os(buffer);
+        os << "content1" << " and more content";
+        buffer.resize(os.size());           // synchronize sizes
+
+        something.write(buffer, buffer.size());
+
+        os.rewind();
+        os << "content2";
+        buffer.resize(os.size());      // synchronize sizes
+
+        something.write(buffer, buffer.size());
+
+        // or simply using the output size directly (without sync)
+        os.rewind();
+        os << "content3";
+
+        something.write(buffer, os.size());
+    \endcode
+
+See Also
+    Foam::ICharStream
+    Foam::ISpanStream
+    Foam::OCharStream
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef Foam_OSpanStream_H
+#define Foam_OSpanStream_H
+
+#include "memoryStreamBuffer.H"
+#include "DynamicList.H"
+#include "OSstream.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+
+// Forward Declarations
+class ospanstream;
+class OSpanStream;
+
+// Older names (prior to 2023-08)
+typedef OSpanStream UOListStream;
+
+
+/*---------------------------------------------------------------------------*\
+                         Class ospanstream Declaration
+\*---------------------------------------------------------------------------*/
+
+//- Similar to std::ostringstream, but with an externally managed output buffer
+//- which makes it most similar to std::ospanstream (C++23)
+class ospanstream
+:
+    virtual public std::ios,
+    protected Foam::memorybuf::out_base,
+    public std::ostream
+{
+    typedef Foam::memorybuf::out_base buffer_type;
+    typedef std::ostream stream_type;
+
+public:
+
+    // Constructors
+
+        //- Default construct - empty
+        ospanstream()
+        :
+            buffer_type(),
+            stream_type(static_cast<buffer_type*>(this))
+        {}
+
+        //- Construct for character array and number of bytes
+        ospanstream(char* buffer, size_t nbytes)
+        :
+            buffer_type(buffer, nbytes),
+            stream_type(static_cast<buffer_type*>(this))
+        {}
+
+        // //- Construct (shallow copy) from span character content
+        // ospanstream(stdFoam::span<char> s)
+        // :
+        //     buffer_type(const_cast<char*>(s.data()), s.size()),
+        //     stream_type(static_cast<buffer_type*>(this))
+        // {}
+
+
+    // Member Functions
+
+        //- The current output position within the buffer (tellp)
+        std::streampos output_pos() const
+        {
+            return buffer_type::span_tellp();
+        }
+
+        //- The put buffer capacity
+        std::streamsize capacity() const
+        {
+            return buffer_type::span_capacity();
+        }
+
+        //- Span of the current output characters (is modifiable!)
+        UList<char> list() const
+        {
+            return buffer_type::span_list();
+        }
+
+        //- Rewind the stream, clearing any old errors
+        void rewind()
+        {
+            buffer_type::pubseekpos(0, std::ios_base::out);
+            stream_type::clear();  // Clear any old errors
+        }
+
+        //- Reset the put buffer area
+        void reset(char* buffer, size_t nbytes)
+        {
+            buffer_type::resetp(buffer, nbytes);
+            stream_type::clear();  // Clear any old errors
+        }
+
+        //- Reset the put buffer area to use the data area from a string
+        void reset(std::string& s)
+        {
+            s.resize(s.capacity());
+            buffer_type::resetp(&s[0], s.size());
+            stream_type::clear();  // Clear any old errors
+        }
+
+        //- Some information about the output buffer position/capacity
+        void debug_info(Ostream& os) const
+        {
+            os  << "put="
+                << output_pos() << '/' << capacity();
+        }
+};
+
+
+namespace Detail
+{
+
+/*---------------------------------------------------------------------------*\
+                Class Detail::OSpanStreamAllocator Declaration
+\*---------------------------------------------------------------------------*/
+
+//- An allocator for holding Foam::ospanstream
+class OSpanStreamAllocator
+{
+protected:
+
+    // Protected Data
+
+        //- The stream
+        Foam::ospanstream stream_;
+
+
+    // Constructors
+
+        //- Default construct (empty)
+        OSpanStreamAllocator() = default;
+};
+
+} // End namespace Detail
+
+
+/*---------------------------------------------------------------------------*\
+                         Class OSpanStream Declaration
+\*---------------------------------------------------------------------------*/
+
+//- An OSstream attached to an unallocated external buffer
+class OSpanStream
+:
+    public Detail::OSpanStreamAllocator,
+    public Foam::OSstream
+{
+    typedef Detail::OSpanStreamAllocator allocator_type;
+
+public:
+
+    // Constructors
+
+        //- Default construct (empty output)
+        explicit OSpanStream
+        (
+            IOstreamOption streamOpt = IOstreamOption()
+        )
+        :
+            allocator_type(),
+            OSstream(stream_, "output", streamOpt.format(), streamOpt.version())
+        {}
+
+        //- Use data area from string content
+        explicit OSpanStream
+        (
+            std::string& buffer,
+            IOstreamOption streamOpt = IOstreamOption()
+        )
+        :
+            OSpanStream(streamOpt)
+        {
+            stream_.reset(buffer);
+        }
+
+        //- Construct using specified buffer and number of bytes
+        OSpanStream
+        (
+            char* buffer,
+            size_t nbytes,
+            IOstreamOption streamOpt = IOstreamOption()
+        )
+        :
+            OSpanStream(streamOpt)
+        {
+            stream_.reset(buffer, nbytes);
+        }
+
+        //- Construct using data area from a List and number of bytes
+        OSpanStream
+        (
+            ::Foam::UList<char>& buffer,
+            size_t nbytes,
+            IOstreamOption streamOpt = IOstreamOption()
+        )
+        :
+            OSpanStream(buffer.data(), nbytes, streamOpt)
+        {}
+
+        //- Construct using data area from a List and its inherent storage size
+        explicit OSpanStream
+        (
+            ::Foam::UList<char>& buffer,
+            IOstreamOption streamOpt = IOstreamOption()
+        )
+        :
+            OSpanStream(buffer.data(), buffer.size(), streamOpt)
+        {}
+
+        //- Construct using full data area from DynamicList
+        template<int SizeMin>
+        explicit OSpanStream
+        (
+            ::Foam::DynamicList<char,SizeMin>& buffer,
+            IOstreamOption streamOpt = IOstreamOption()
+        )
+        :
+            OSpanStream(buffer.data(), buffer.capacity(), streamOpt)
+        {
+            buffer.resize(buffer.capacity());  // Uses entire space
+        }
+
+
+    // Member Functions
+
+        //- Position of the put buffer
+        std::streampos tellp() const { return stream_.output_pos(); }
+
+        //- The current output position within the buffer (tellp)
+        std::streampos output_pos() const { return stream_.output_pos(); }
+
+        //- The current output size. Same as tellp(), output_pos()
+        label size() const { return label(stream_.output_pos()); }
+
+        //- The put buffer capacity
+        std::streamsize capacity() const { return stream_.capacity(); }
+
+        //- Span of the current output characters (is modifiable!)
+        UList<char> list() const { return stream_.list(); }
+
+        //- Reset the put area
+        void reset(char* buffer, size_t nbytes)
+        {
+            stream_.reset(buffer, nbytes);
+            syncState();
+        }
+
+        //- Reset the put buffer area to use the data area from a string
+        void reset(std::string& s)
+        {
+            stream_.reset(s);
+            syncState();
+        }
+
+        //- Rewind the stream, clearing any old errors
+        virtual void rewind()
+        {
+            stream_.rewind();
+            syncState();
+        }
+
+        //- Print stream description to Ostream
+        virtual void print(Ostream& os) const;
+};
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //

src/OpenFOAM/db/IOstreams/memory/SpanStream.H

@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2017 OpenCFD Ltd.
+    Copyright (C) 2017-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -24,15 +24,17 @@ License
     along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
 
 Description
-    Input/output streams with managed List storage.
+    Input/output streams with (internal or external) character storage.
 
 \*---------------------------------------------------------------------------*/
 
-#ifndef ListStream_H
-#define ListStream_H
+#ifndef Foam_SpanStream_H
+#define Foam_SpanStream_H
 
-#include "IListStream.H"
-#include "OListStream.H"
+#include "ISpanStream.H"
+#include "ICharStream.H"
+#include "OSpanStream.H"
+#include "OCharStream.H"
 
 #endif
 

src/OpenFOAM/db/IOstreams/memory/SpanStreams.C

@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2017 OpenCFD Ltd.
+    Copyright (C) 2017-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -25,40 +25,39 @@ License
 
 \*---------------------------------------------------------------------------*/
 
-#include "UListStream.H"
-#include "ListStream.H"
+#include "SpanStream.H"
 #include "OCountStream.H"
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
-void Foam::IListStream::print(Ostream& os) const
+void Foam::ISpanStream::print(Ostream& os) const
 {
-    os  << "IListStream: ";
-    printBufInfo(os);
+    os  << "ISpanStream: ";
+    stream_.debug_info(os);
     os  << Foam::endl;
 }
 
 
-void Foam::UIListStream::print(Ostream& os) const
+void Foam::OSpanStream::print(Ostream& os) const
 {
-    os  << "UIListStream: ";
-    printBufInfo(os);
+    os  << "OSpanStream: ";
+    stream_.debug_info(os);
     os  << Foam::endl;
 }
 
 
-void Foam::OListStream::print(Ostream& os) const
+void Foam::ICharStream::print(Ostream& os) const
 {
-    os  << "OListStream: ";
-    printBufInfo(os);
+    os  << "ICharStream: ";
+    stream_.debug_info(os);
     os  << Foam::endl;
 }
 
 
-void Foam::UOListStream::print(Ostream& os) const
+void Foam::OCharStream::print(Ostream& os) const
 {
-    os  << "UOListStream: ";
-    printBufInfo(os);
+    os  << "OCharStream: ";
+    stream_.debug_info(os);
     os  << Foam::endl;
 }
 
@@ -66,7 +65,8 @@ void Foam::UOListStream::print(Ostream& os) const
 void Foam::OCountStream::print(Ostream& os) const
 {
     os  << "OCountStream: ";
-    printBufInfo(os);
+    // os  << "count=" << stream_.count();
+    stream_.debug_info(os);
     os  << Foam::endl;
 }
 

src/OpenFOAM/db/IOstreams/memory/UIListStream.H

@@ -1,326 +0,0 @@
-/*---------------------------------------------------------------------------*\
-  =========                 |
-  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
-   \\    /   O peration     |
-    \\  /    A nd           | www.openfoam.com
-     \\/     M anipulation  |
--------------------------------------------------------------------------------
-    Copyright (C) 2016-2022 OpenCFD Ltd.
--------------------------------------------------------------------------------
-License
-    This file is part of OpenFOAM.
-
-    OpenFOAM is free software: you can redistribute it and/or modify it
-    under the terms of the GNU General Public License as published by
-    the Free Software Foundation, either version 3 of the License, or
-    (at your option) any later version.
-
-    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
-    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
-    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
-    for more details.
-
-    You should have received a copy of the GNU General Public License
-    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
-
-Class
-    Foam::UIListStream
-
-Description
-    Similar to IStringStream but using an externally managed buffer for its
-    input. This allows the input buffer to be filled (and refilled) from
-    various sources.
-
-    Note that this stream will normally be used as a "one-shot" reader.
-    Caution must be exercised that the referenced buffer remains valid and
-    without any intermediate resizing for the duration of the stream's use.
-
-    An example of possible use:
-    \code
-        DynamicList<char> buffer(4096);     // allocate some large buffer
-
-        nread = something.read(buffer.data(),1024); // fill with content
-        buffer.resize(nread);               // content size
-
-        // Construct dictionary, or something else
-        UIListStream is(buffer)
-        dictionary dict1(is);
-
-        // Sometime later
-        nread = something.read(buffer.data(),2048); // fill with content
-        buffer.resize(nread);               // content size
-
-        // Without intermediate variable
-        dictionary dict2(UIListStream(buffer)());
-    \endcode
-
-See Also
-    Foam::IListStream
-    Foam::OListStream
-    Foam::UOListStream
-
-\*---------------------------------------------------------------------------*/
-
-#ifndef Foam_UIListStream_H
-#define Foam_UIListStream_H
-
-#include "UList.H"
-#include "ISstream.H"
-#include "memoryStreamBuffer.H"
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-namespace Foam
-{
-
-/*---------------------------------------------------------------------------*\
-                        Class uiliststream Declaration
-\*---------------------------------------------------------------------------*/
-
-//- Similar to std::istringstream, but with an externally managed input buffer.
-//  This allows the input buffer to be filled or refilled from various sources
-//  without copying.
-class uiliststream
-:
-    virtual public std::ios,
-    protected memorybuf::in,
-    public std::istream
-{
-public:
-
-    //- Construct for character array and number of bytes
-    uiliststream(const char* buffer, size_t nbytes)
-    :
-        memorybuf::in(const_cast<char*>(buffer), nbytes),
-        std::istream(static_cast<memorybuf::in*>(this))
-    {}
-
-    //- Reset buffer pointers
-    inline void reset(char *buffer, size_t nbytes)
-    {
-        resetg(buffer, nbytes);
-    }
-
-    //- Rewind the stream, clearing any old errors
-    void rewind()
-    {
-        this->pubseekpos(0, std::ios_base::in);
-        clear(); // for safety, clear any old errors
-    }
-};
-
-
-namespace Detail
-{
-
-/*---------------------------------------------------------------------------*\
-                Class Detail::UIListStreamAllocator Declaration
-\*---------------------------------------------------------------------------*/
-
-//- An stream/stream-buffer input allocator for a externally allocated list
-class UIListStreamAllocator
-{
-protected:
-
-    // Protected Data
-
-        typedef std::istream stream_type;
-
-        //- The stream buffer
-        memorybuf::in buf_;
-
-        //- The stream
-        stream_type stream_;
-
-
-    // Constructors
-
-        //- Construct for character array and number of bytes
-        UIListStreamAllocator(char* buffer, size_t nbytes)
-        :
-            buf_(buffer, nbytes),
-            stream_(&buf_)
-        {}
-
-
-    // Protected Member Functions
-
-        //- Reset buffer pointers
-        inline void reset(char* buffer, size_t nbytes)
-        {
-            buf_.resetg(buffer, nbytes);
-        }
-
-        void printBufInfo(Ostream& os) const
-        {
-            buf_.printBufInfo(os);
-        }
-
-public:
-
-    // Member Functions
-
-        //- Const UList access to the input characters (shallow copy).
-        inline const UList<char> list() const
-        {
-            return buf_.list();
-        }
-
-        //- Non-const UList access to the input characters (shallow copy).
-        inline UList<char> list()
-        {
-            return buf_.list();
-        }
-
-        //- The list size
-        inline label size() const
-        {
-            return buf_.capacity();
-        }
-
-        //- Position of the get buffer
-        std::streampos tellg() const
-        {
-            return buf_.tellg();
-        }
-
-        //- Move to buffer start, clear errors
-        void rewind()
-        {
-            buf_.pubseekpos(0, std::ios_base::in);
-            stream_.clear(); // for safety, clear any old errors
-        }
-};
-
-} // End namespace Detail
-
-
-/*---------------------------------------------------------------------------*\
-                         Class UIListStream Declaration
-\*---------------------------------------------------------------------------*/
-
-class UIListStream
-:
-    public Detail::UIListStreamAllocator,
-    public ISstream
-{
-    typedef Detail::UIListStreamAllocator allocator_type;
-
-public:
-
-    // Constructors
-
-        //- Construct using specified buffer and number of bytes
-        UIListStream
-        (
-            const char* buffer,
-            size_t nbytes,
-            IOstreamOption streamOpt = IOstreamOption()
-        )
-        :
-            allocator_type(const_cast<char*>(buffer), nbytes),
-            ISstream(stream_, "input", streamOpt.format(), streamOpt.version())
-        {}
-
-        //- Construct using data area from a List and number of bytes
-        UIListStream
-        (
-            const UList<char>& buffer,
-            size_t nbytes,
-            IOstreamOption streamOpt = IOstreamOption()
-        )
-        :
-            UIListStream(buffer.cdata(), nbytes, streamOpt)
-        {}
-
-        //- Construct using data area from a List and its inherent storage size
-        //  Uses addressed size, thus no special treatment for a DynamicList
-        explicit UIListStream
-        (
-            const UList<char>& buffer,
-            IOstreamOption streamOpt = IOstreamOption()
-        )
-        :
-            UIListStream(buffer.cdata(), buffer.size(), streamOpt)
-        {}
-
-
-    // Member Functions
-
-        //- Return the current get position in the buffer
-        std::streampos pos() const
-        {
-            return allocator_type::tellg();
-        }
-
-        //- Rewind the stream, clearing any old errors
-        virtual void rewind()
-        {
-            allocator_type::rewind();
-            setGood();  // resynchronize with internal state
-        }
-
-        //- Print stream description to Ostream
-        virtual void print(Ostream& os) const;
-
-
-    // Member Operators
-
-        //- A non-const reference to const Istream
-        //  Needed for read-constructors where the stream argument is temporary
-        Istream& operator()() const
-        {
-            // Could also rewind
-            return const_cast<UIListStream&>(*this);
-        }
-
-
-    // Additional constructors and methods (as per v2012 and earlier)
-    #ifdef Foam_IOstream_extras
-
-        //- Construct using specified buffer and number of bytes
-        UIListStream
-        (
-            const char* buffer,
-            size_t nbytes,
-            IOstreamOption::streamFormat fmt
-        )
-        :
-            UIListStream(buffer, nbytes, IOstreamOption(fmt))
-        {}
-
-        //- Construct using data area from a List and number of bytes
-        UIListStream
-        (
-            const UList<char>& buffer,
-            size_t nbytes,
-            IOstreamOption::streamFormat fmt
-        )
-        :
-            UIListStream(buffer.cdata(), nbytes, IOstreamOption(fmt))
-        {}
-
-        //- Construct using data area from a List and its inherent storage size
-        //  Uses addressed size, thus no special treatment for a DynamicList
-        UIListStream
-        (
-            const UList<char>& buf,
-            IOstreamOption::streamFormat fmt
-        )
-        :
-            UIListStream(buf.cdata(), buf.size(), IOstreamOption(fmt))
-        {}
-
-    #endif /* Foam_IOstream_extras */
-};
-
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-} // End namespace Foam
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-#endif
-
-// ************************************************************************* //

src/OpenFOAM/db/IOstreams/memory/UListStream.H

@@ -1,39 +0,0 @@
-/*---------------------------------------------------------------------------*\
-  =========                 |
-  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
-   \\    /   O peration     |
-    \\  /    A nd           | www.openfoam.com
-     \\/     M anipulation  |
--------------------------------------------------------------------------------
-    Copyright (C) 2017 OpenCFD Ltd.
--------------------------------------------------------------------------------
-License
-    This file is part of OpenFOAM.
-
-    OpenFOAM is free software: you can redistribute it and/or modify it
-    under the terms of the GNU General Public License as published by
-    the Free Software Foundation, either version 3 of the License, or
-    (at your option) any later version.
-
-    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
-    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
-    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
-    for more details.
-
-    You should have received a copy of the GNU General Public License
-    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
-
-Description
-    Input/output streams with externally managed storage.
-
-\*---------------------------------------------------------------------------*/
-
-#ifndef UListStream_H
-#define UListStream_H
-
-#include "UIListStream.H"
-#include "UOListStream.H"
-
-#endif
-
-// ************************************************************************* //

src/OpenFOAM/db/IOstreams/memory/UOListStream.H

@@ -1,326 +0,0 @@
-/*---------------------------------------------------------------------------*\
-  =========                 |
-  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
-   \\    /   O peration     |
-    \\  /    A nd           | www.openfoam.com
-     \\/     M anipulation  |
--------------------------------------------------------------------------------
-    Copyright (C) 2016-2022 OpenCFD Ltd.
--------------------------------------------------------------------------------
-License
-    This file is part of OpenFOAM.
-
-    OpenFOAM is free software: you can redistribute it and/or modify it
-    under the terms of the GNU General Public License as published by
-    the Free Software Foundation, either version 3 of the License, or
-    (at your option) any later version.
-
-    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
-    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
-    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
-    for more details.
-
-    You should have received a copy of the GNU General Public License
-    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
-
-Class
-    Foam::UOListStream
-
-Description
-    Similar to OStringStream but using an externally managed buffer for
-    its output.
-
-    This allows the output buffer to be reused and can make it easier when
-    writing out data.  It is the user's responsibility to ensure proper
-    synchronization in the sizes. Provided that the external buffer is large
-    enough that overflow does not occur, the following usage pattern
-    works.
-
-    \code
-        DynamicList<char> buffer(4096);     // allocate some large buffer
-
-        {
-            UOListStream os(buffer);
-            os << "content1" << " and more content";
-            buffer.resize(os.size());       // synchronize sizes
-        }
-
-        something.write(buffer, buffer.size());
-    \endcode
-
-    Although the UOListStream is quite lightweight, there may be cases
-    where it is preferable to reuse the stream as well.
-    \code
-        DynamicList<char> buffer(4096);     // allocate some large buffer
-
-        UOListStream os(buffer);
-        os << "content1" << " and more content";
-        buffer.resize(os.size());           // synchronize sizes
-
-        something.write(buffer, buffer.size());
-
-        os.rewind();
-        os << "content2";
-        buffer.resize(os.size());      // synchronize sizes
-
-        something.write(buffer, buffer.size());
-
-        // or simply using the output size directly (without sync)
-        os.rewind();
-        os << "content3";
-
-        something.write(buffer, os.size());
-    \endcode
-
-See Also
-    Foam::IListStream
-    Foam::OListStream
-    Foam::UIListStream
-
-\*---------------------------------------------------------------------------*/
-
-#ifndef Foam_UOListStream_H
-#define Foam_UOListStream_H
-
-#include "DynamicList.H"
-#include "FixedList.H"
-#include "OSstream.H"
-#include "memoryStreamBuffer.H"
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-namespace Foam
-{
-
-namespace Detail
-{
-
-/*---------------------------------------------------------------------------*\
-                Class Detail::UOListStreamAllocator Declaration
-\*---------------------------------------------------------------------------*/
-
-//- An stream/stream-buffer allocator for external buffers
-class UOListStreamAllocator
-{
-protected:
-
-    // Protected Data
-
-        typedef std::ostream stream_type;
-
-        //- The stream buffer
-        memorybuf::out buf_;
-
-        //- The stream
-        stream_type stream_;
-
-
-    // Constructors
-
-        //- Construct for character array and number of bytes
-        UOListStreamAllocator(char* buffer, size_t nbytes)
-        :
-            buf_(buffer, nbytes),
-            stream_(&buf_)
-        {}
-
-        void printBufInfo(Ostream& os) const
-        {
-            buf_.printBufInfo(os);
-        }
-
-public:
-
-    // Member Functions
-
-        //- Const UList access to the characters written (shallow copy).
-        inline const UList<char> list() const
-        {
-            return buf_.list();
-        }
-
-        //- Non-const UList access to the characters written (shallow copy).
-        inline UList<char> list()
-        {
-            return buf_.list();
-        }
-
-        //- The current list output capacity
-        inline label capacity() const
-        {
-            return buf_.capacity();
-        }
-
-        //- The current output position in the buffer,
-        //- which is also the addressed list size
-        inline label size() const
-        {
-            return buf_.tellp();
-        }
-
-        //- Move to buffer start, clear errors
-        void rewind()
-        {
-            buf_.pubseekpos(0, std::ios_base::out);
-            stream_.clear(); // for safety, clear any old errors
-        }
-};
-
-} // End namespace Detail
-
-
-/*---------------------------------------------------------------------------*\
-                         Class UOListStream Declaration
-\*---------------------------------------------------------------------------*/
-
-//- An OSstream attached to an unallocated external buffer
-class UOListStream
-:
-    public Detail::UOListStreamAllocator,
-    public OSstream
-{
-    typedef Detail::UOListStreamAllocator allocator_type;
-
-public:
-
-    // Constructors
-
-        //- Construct using specified buffer and number of bytes
-        UOListStream
-        (
-            char* buffer,
-            size_t nbytes,
-            IOstreamOption streamOpt = IOstreamOption()
-        )
-        :
-            allocator_type(buffer, nbytes),
-            OSstream(stream_, "output", streamOpt.format(), streamOpt.version())
-        {}
-
-        //- Construct using data area from a List and number of bytes
-        UOListStream
-        (
-            UList<char>& buffer,
-            size_t nbytes,
-            IOstreamOption streamOpt = IOstreamOption()
-        )
-        :
-            UOListStream(buffer.data(), nbytes, streamOpt)
-        {}
-
-        //- Construct using data area from a List and its inherent storage size
-        explicit UOListStream
-        (
-            UList<char>& buffer,
-            IOstreamOption streamOpt = IOstreamOption()
-        )
-        :
-            UOListStream(buffer.data(), buffer.size(), streamOpt)
-        {}
-
-        //- Construct using data area from a FixedList
-        template<unsigned N>
-        explicit UOListStream
-        (
-            FixedList<char, N>& buffer,
-            IOstreamOption streamOpt = IOstreamOption()
-        )
-        :
-            UOListStream(buffer.data(), N, streamOpt)
-        {}
-
-        //- Construct using data area from a DynamicList and its capacity
-        template<int SizeMin>
-        explicit UOListStream
-        (
-            DynamicList<char,SizeMin>& buffer,
-            IOstreamOption streamOpt = IOstreamOption()
-        )
-        :
-            UOListStream(buffer.data(), buffer.capacity(), streamOpt)
-        {}
-
-
-    // Member Functions
-
-        //- Rewind the stream, clearing any old errors
-        virtual void rewind()
-        {
-            allocator_type::rewind();
-            setGood();  // resynchronize with internal state
-        }
-
-        //- Print stream description to Ostream
-        virtual void print(Ostream& os) const;
-
-
-    // Additional constructors and methods (as per v2012 and earlier)
-    #ifdef Foam_IOstream_extras
-
-        //- Construct using specified buffer and number of bytes
-        UOListStream
-        (
-            char* buffer,
-            size_t nbytes,
-            IOstreamOption::streamFormat fmt
-        )
-        :
-            UOListStream(buffer, nbytes, IOstreamOption(fmt))
-        {}
-
-        //- Construct using data area from a List and number of bytes
-        UOListStream
-        (
-            UList<char>& buffer,
-            size_t nbytes,
-            IOstreamOption::streamFormat fmt
-        )
-        :
-            UOListStream(buffer.data(), nbytes, IOstreamOption(fmt))
-        {}
-
-        //- Construct using data area from a List and its inherent storage size
-        UOListStream
-        (
-            UList<char>& buffer,
-            IOstreamOption::streamFormat fmt
-        )
-        :
-            UOListStream(buffer.data(), buffer.size(), IOstreamOption(fmt))
-        {}
-
-        //- Construct using data area from a FixedList
-        template<unsigned N>
-        UOListStream
-        (
-            FixedList<char, N>& buffer,
-            IOstreamOption::streamFormat fmt
-        )
-        :
-            UOListStream(buffer.data(), N, IOstreamOption(fmt))
-        {}
-
-        //- Construct using data area from a DynamicList and its capacity
-        template<int SizeMin>
-        UOListStream
-        (
-            DynamicList<char,SizeMin>& buf,
-            IOstreamOption::streamFormat fmt
-        )
-        :
-            UOListStream(buf.data(), buf.capacity(), IOstreamOption(fmt))
-        {}
-
-    #endif /* Foam_IOstream_extras */
-};
-
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-} // End namespace Foam
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-#endif
-
-// ************************************************************************* //

src/OpenFOAM/db/IOstreams/memory/memoryStreamBuffer.H

@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2016-2020 OpenCFD Ltd.
+    Copyright (C) 2016-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -28,16 +28,19 @@ Class
 
 Description
     A std::streambuf used for memory buffer streams such as
-    UIListStream, UOListStream, etc.
+    ispanstream, ocharstream, etc.
 
 \*---------------------------------------------------------------------------*/
 
 #ifndef Foam_memoryStreamBuffer_H
 #define Foam_memoryStreamBuffer_H
 
+#include "stdFoam.H"  // For span
 #include "UList.H"
+
+#include <memory>
+#include <sstream>    // Possibly want stringstream too...
 #include <type_traits>
-#include <sstream>
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
@@ -48,7 +51,7 @@ namespace Foam
                           Class memorybuf Declaration
 \*---------------------------------------------------------------------------*/
 
-//- A streambuf for memory
+//- A streambuf for memory similar to std::spanbuf (C++23)
 class memorybuf
 :
     public std::streambuf
@@ -106,11 +109,11 @@ protected:
 
         if (testin)
         {
-            return (gptr() - eback()); // tellg()
+            return (gptr() - eback()); // span_tellg()
         }
         if (testout)
         {
-            return (pptr() - pbase()); // tellp()
+            return (pptr() - pbase()); // span_tellp()
         }
 
         return -1;
@@ -127,126 +130,322 @@ protected:
         return seekoff(pos, std::ios_base::beg, which);
     }
 
-
-    //- \return the current buffer get position
-    inline std::streamsize tellg() const
-    {
-        return (gptr() - eback());
-    }
-
-    //- \return the current buffer put position
-    inline std::streamsize tellp() const
-    {
-        return (pptr() - pbase());
-    }
-
-
 public:
 
     // Forward Declarations
-    class in;
-    class out;
+    class in_base;
+    class in_dynamic;
+    class out_base;
+    class out_dynamic;
 };
 
 
 /*---------------------------------------------------------------------------*\
-                        Class memorybuf::in Declaration
+                     Class memorybuf::in_base Declaration
 \*---------------------------------------------------------------------------*/
 
-//- An input streambuf for memory access
-class memorybuf::in
+//- The base input streambuf with memory access
+class memorybuf::in_base
 :
     public memorybuf
 {
 protected:
 
-    //- Default construct
-    in() = default;
-
-    //- Get sequence of characters
+    //- Get sequence of characters from a fixed region
     virtual std::streamsize xsgetn(char* s, std::streamsize n)
     {
         std::streamsize count = 0;
-
         while (count < n && gptr() < egptr())
         {
             *(s + count++) = *(gptr());
             gbump(1);
         }
-
         return count;
     }
 
-
 public:
 
-    //- Construct for character array (can be nullptr) and number of bytes
-    in(char* s, std::streamsize n)
-    {
-        resetg(s, n);
-    }
+    // Constructors
 
-    //- Reset for character array (can be nullptr) and number of bytes
-    //  Sets get pointer to the begin.
-    inline void resetg(char* s, std::streamsize n)
-    {
-        if (s)
+        //- Default construct
+        in_base() = default;
+
+        //- Construct for character array (can be nullptr) and number of bytes
+        in_base(char* s, std::streamsize n)
         {
-            setg(s, s, s + n);
+            resetg(s, n);
         }
-        else
+
+
+    // Member Functions
+
+        // //- Reset get buffer pointer to the beginning of existing span
+        // void rewind() { setg(eback(), eback(), egptr()); }
+
+        //- Reset get buffer with character data (can be nullptr) and count
+        //  Sets get pointer to the begin.
+        void resetg(char* s, std::streamsize n)
         {
-            setg(nullptr, nullptr, nullptr);
+            if (s)
+            {
+                setg(s, s, s + n);
+            }
+            else
+            {
+                setg(nullptr, nullptr, nullptr);
+            }
         }
-    }
 
-    //- The buffer get position
-    using memorybuf::tellg;
+        //- The current buffer get position
+        std::streamsize span_tellg() const { return (gptr() - eback()); }
 
-    //- The buffer capacity
-    inline std::streamsize capacity() const
-    {
-        return (egptr() - eback());
-    }
+        //- The get buffer capacity
+        std::streamsize span_capacity() const { return (egptr() - eback()); }
 
-    //- Const UList access to the input characters (shallow copy).
-    inline const UList<char> list() const
-    {
-        return UList<char>(eback(), (egptr() - eback()));
-    }
+        //- The number of characters remaining in the get area
+        std::streamsize span_remaining() const
+        {
+            return (gptr() < egptr()) ? (egptr() - gptr()) : 0;
+        }
 
-    //- Non-const UList access to the input characters (shallow copy).
-    inline UList<char> list()
-    {
-        return UList<char>(eback(), (egptr() - eback()));
-    }
+        //- Span of the input characters (is modifiable!)
+        UList<char> span_list() const
+        {
+            return UList<char>(eback(), (egptr() - eback()));
+        }
 
-    //- Some information about the input buffer position/capacity
-    inline void printBufInfo(Ostream& os) const
-    {
-        os  << "get=" << (gptr() - eback()) // tellp()
-            << "/" << (egptr() - eback());  // capacity
-    }
+        // //- The span of input characters (is modifiable!)
+        // stdFoam::span<char> span() const
+        // {
+        //     return stdFoam::span<char>(eback(), (egptr() - eback()));
+        // }
+
+        //- Some information about the input buffer position/capacity
+        void info(Ostream& os) const
+        {
+            os  << "get=" << span_tellg() << '/' << span_capacity();
+        }
 };
 
 
 /*---------------------------------------------------------------------------*\
-                       Class memorybuf::out Declaration
+                    Class memorybuf::in_dynamic Declaration
 \*---------------------------------------------------------------------------*/
 
 //- An output streambuf for memory access
-class memorybuf::out
+class memorybuf::in_dynamic
+:
+    public memorybuf::in_base
+{
+private:
+
+    //- Character storage
+    List<char> storage_;
+
+
+public:
+
+    // Constructors
+
+        //- Default construct - empty
+        in_dynamic() = default;
+
+        //- Copy construct from content
+        in_dynamic(const char* s, std::streamsize n)
+        {
+            if (s && n)
+            {
+                storage_.resize_nocopy(n);
+                std::copy(s, (s + n), storage_.data());
+            }
+            sync_gbuffer();
+        }
+
+        //- Move construct from List
+        in_dynamic(::Foam::List<char>&& buffer)
+        :
+            storage_(std::move(buffer))
+        {
+            sync_gbuffer();
+        }
+
+        //- Move construct from DynamicList (added length only)
+        template<int SizeMin>
+        in_dynamic(::Foam::DynamicList<char,SizeMin>&& buffer)
+        {
+            storage_.transfer(buffer);
+            sync_gbuffer();
+        }
+
+
+    // Member Functions
+
+        //- Sync get buffer pointers to agree with list dimensions
+        //  Sets get pointer to the begin (rewind).
+        void sync_gbuffer()
+        {
+            resetg(storage_.data(), storage_.size());
+        }
+
+        //- Reset content (copy)
+        void reset(const char* s, std::streamsize n)
+        {
+            if (s && n)
+            {
+                storage_.resize_nocopy(n);
+                std::copy(s, (s + n), storage_.data());
+            }
+            else
+            {
+                storage_.clear();
+            }
+            sync_gbuffer();
+        }
+
+        //- Transfer list contents to List buffer
+        void swap(::Foam::List<char>& other)
+        {
+            storage_.swap(other);  // Swap contents
+            sync_gbuffer();
+        }
+
+        //- Transfer list contents to a DynamicList buffer
+        template<int SizeMin>
+        void swap(DynamicList<char,SizeMin>& other)
+        {
+            List<char> tmp(std::move(storage_));
+
+            other.shrink();             // Use addressed length only
+            storage_.transfer(other);
+            other.transfer(tmp);
+            sync_gbuffer();
+        }
+};
+
+
+/*---------------------------------------------------------------------------*\
+                     Class memorybuf::out_base Declaration
+\*---------------------------------------------------------------------------*/
+
+//- An output streambuf for memory access
+class memorybuf::out_base
 :
     public memorybuf
 {
 protected:
 
-    //- Default construct
-    out() = default;
+    //- Put sequence of characters to a fixed region
+    virtual std::streamsize xsputn(const char* s, std::streamsize n)
+    {
+        std::streamsize count = 0;
+        while (count < n && pptr() < epptr())
+        {
+            *(pptr()) = *(s + count++);
+            pbump(1);
+        }
+        return count;
+    }
+
+public:
+
+    // Constructors
+
+        //- Default construct
+        out_base() = default;
+
+        //- Construct for character array (can be nullptr) and number of bytes
+        out_base(char* s, std::streamsize n)
+        {
+            resetp(s, n);
+        }
+
+
+    // Member Functions
+
+        // //- Reset put buffer pointer to the beginning of existing span
+        // void rewind() { setp(pbase(), epptr()); }
+
+        //- Reset put buffer with character data (can be nullptr) and count
+        //  Sets put pointer to the begin.
+        inline void resetp(char* s, std::streamsize n)
+        {
+            if (s)
+            {
+                // As per (std::ios_base::out && !std::ios_base::ate)
+                setp(s, s + n);
+                // No treatment for (std::ios_base::out && std::ios_base::ate)
+            }
+            else
+            {
+                setp(nullptr, nullptr);
+            }
+        }
+
+        //- The current buffer put position
+        std::streamsize span_tellp() const { return (pptr() - pbase()); }
+
+        //- The put buffer capacity
+        std::streamsize span_capacity() const { return (epptr() - pbase()); }
+
+        //- Span of the output characters (is modifiable!)
+        UList<char> span_list() const
+        {
+            return UList<char>(pbase(), (pptr() - pbase()));
+        }
+
+        //- The span of output characters (is modifiable!)
+        // stdFoam::span<char> span() const
+        // {
+        //     return stdFoam::span<char>(pbase(), (pptr() - pbase()));
+        // }
+
+        //- Some information about the output buffer position/capacity
+        void info(Ostream& os) const
+        {
+            os  << "put=" << span_tellp() << '/' << span_capacity();
+        }
+};
+
+
+/*---------------------------------------------------------------------------*\
+                   Class memorybuf::out_dynamic Declaration
+\*---------------------------------------------------------------------------*/
+
+//- An output streambuf for memory access
+class memorybuf::out_dynamic
+:
+    public memorybuf::out_base
+{
+private:
+
+    //- Character storage.
+    //  Internally manage like a DynamicList, with its capacity known
+    //  from the list size and the addressable size known through the
+    //  stream pointers.
+    List<char> storage_;
+
+protected:
+
+    //- Handle overflow
+    virtual int overflow(int_type c = traits_type::eof())
+    {
+        if (c != traits_type::eof())
+        {
+            // Need more space?
+            reserve(1 + span_tellp());
+
+            *(pptr()) = c;
+            pbump(1);
+        }
+        return c;
+    }
 
     //- Put sequence of characters
     virtual std::streamsize xsputn(const char* s, std::streamsize n)
     {
+        // Enough space so that appends work without problem
+        reserve(n + span_tellp());
+
         std::streamsize count = 0;
         while (count < n && pptr() < epptr())
         {
@@ -260,53 +459,111 @@ protected:
 
 public:
 
-    //- Construct for character array (can be nullptr) and number of bytes
-    out(char* s, std::streamsize n)
-    {
-        resetp(s, n);
-    }
+    // Constructors
 
-    //- Reset for character array (can be nullptr) and number of bytes.
-    //  Sets put pointer to the begin.
-    inline void resetp(char* s, std::streamsize n)
-    {
-        if (s)
+        //- Default construct with initial reserved number of bytes.
+        //  The value of 512 is a bit arbitrary, but consistent with
+        //  std::stringstream
+        out_dynamic(size_t nbytes = 512)
+        :
+            storage_(label(nbytes))
         {
-            setp(s, s + n);
+            sync_pbuffer();
         }
-        else
+
+        //- Move construct from List
+        out_dynamic(::Foam::List<char>&& buffer)
+        :
+            storage_(std::move(buffer))
         {
-            setp(nullptr, nullptr);
+            sync_pbuffer();
         }
-    }
 
-    //- The buffer put position
-    using memorybuf::tellp;
+        //- Move construct from DynamicList (uses entire capacity)
+        template<int SizeMin>
+        out_dynamic(::Foam::DynamicList<char,SizeMin>&& buffer)
+        {
+            buffer.resize(buffer.capacity());  // Use entire space
+            storage_.transfer(buffer);
+            sync_pbuffer();
+        }
 
-    //- The buffer capacity
-    inline std::streamsize capacity() const
-    {
-        return (epptr() - pbase());
-    }
 
-    //- Const UList access to the characters written (shallow copy).
-    inline const UList<char> list() const
-    {
-        return UList<char>(pbase(), (pptr() - pbase()));
-    }
+    // Member Functions
 
-    //- Non-const UList access to the characters written (shallow copy).
-    inline UList<char> list()
-    {
-        return UList<char>(pbase(), (pptr() - pbase()));
-    }
+        //- Increment capacity (if needed) and adjust buffer pointers
+        void reserve(const std::streamsize len)
+        {
+            if (storage_.size() < len)
+            {
+                const auto cur = span_tellp();   // Current location
 
-    //- Some information about the output buffer position/capacity
-    inline void printBufInfo(Ostream& os) const
-    {
-        os  << "put=" << (pptr() - pbase()) // tellp()
-            << "/" << (epptr() - pbase());  // capacity
-    }
+                label newCapacity = 512;
+
+                if (newCapacity < len)
+                {
+                    // Increase capacity (doubling)
+                    newCapacity = max(len, label(2*storage_.size()));
+                }
+
+                // Info<<"request:" << len
+                //     << " cur cap:" << storage_.size()
+                //     << " new cap:" << newCapacity
+                //     << " pos:" << cur << endl;
+
+                storage_.resize(newCapacity);
+                sync_pbuffer();
+                pbump(cur);
+            }
+        }
+
+        //- Sync put buffer pointers to agree with list dimensions
+        //  Sets put pointer to the begin (rewind).
+        void sync_pbuffer()
+        {
+            resetp(storage_.data(), storage_.size());
+        }
+
+        //- Clear storage
+        void clearStorage()
+        {
+            storage_.clear();
+            sync_pbuffer();
+        }
+
+        //- Shrink storage to addressed storage
+        inline void shrink()
+        {
+            const auto cur = span_tellp();   // Addressed length
+
+            storage_.resize(cur);
+            sync_pbuffer();
+            pbump(cur);
+        }
+
+        //- Transfer list contents to List buffer
+        inline void swap(List<char>& other)
+        {
+            const auto cur = span_tellp(); // Addressed length
+
+            storage_.swap(other);       // Swap contents
+            other.resize(cur);          // Adjust to addressed length
+            sync_pbuffer();
+        }
+
+        //- Transfer list contents to a DynamicList buffer
+        template<int SizeMin>
+        inline void swap(DynamicList<char,SizeMin>& other)
+        {
+            const auto cur = span_tellp();   // Addressed length
+            List<char> tmp(std::move(storage_));
+
+            other.resize(other.capacity());  // Use entire space
+            storage_.transfer(other);
+            other.transfer(tmp);
+            other.resize(cur);          // Adjust to addressed length
+            sync_pbuffer();
+        }
 };
 
 

src/OpenFOAM/db/dynamicLibrary/dynamicCode/dynamicCodeContext.C

@@ -28,7 +28,6 @@ License
 
 #include "dynamicCodeContext.H"
 #include "stringOps.H"
-#include "OSHA1stream.H"
 
 // * * * * * * * * * * * * * Static Member Functions * * * * * * * * * * * * //
 

src/OpenFOAM/db/error/error.C

@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2014 OpenFOAM Foundation
-    Copyright (C) 2015-2021 OpenCFD Ltd.
+    Copyright (C) 2015-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -37,8 +37,24 @@ Note
 #include "StringStream.H"
 #include "foamVersion.H"
 #include "OSspecific.H"
+#include "Enum.H"
 #include "Switch.H"
 
+// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
+
+const Foam::Enum
+<
+    Foam::error::handlerTypes
+>
+Foam::error::handlerNames
+({
+    { handlerTypes::DEFAULT, "default" },
+    { handlerTypes::IGNORE, "ignore" },
+    { handlerTypes::WARN, "warn" },
+    { handlerTypes::STRICT, "strict" },
+});
+
+
 // * * * * * * * * * * * * * Static Member Functions * * * * * * * * * * * * //
 
 bool Foam::error::master(const label communicator)

src/OpenFOAM/db/error/error.H

@@ -53,8 +53,8 @@ SeeAlso
 
 \*---------------------------------------------------------------------------*/
 
-#ifndef error_H
-#define error_H
+#ifndef Foam_error_H
+#define Foam_error_H
 
 #include "messageStream.H"
 #include <memory>
@@ -66,6 +66,7 @@ namespace Foam
 
 // Forward Declarations
 class OStringStream;
+template<class EnumType> class Enum;
 
 /*---------------------------------------------------------------------------*\
                             Class error Declaration
@@ -101,6 +102,21 @@ protected:
 
 public:
 
+    // Data Types
+
+        //- Handling of errors. The exact handling depends on the local context.
+        enum class handlerTypes : char
+        {
+            DEFAULT = 0,  //!< Default behaviour (local meaning)
+            IGNORE,       //!< Ignore on errors/problems
+            WARN,         //!< Warn on errors/problems
+            STRICT        //!< Fatal on errors/problems
+        };
+
+        //- Names of the error handler types
+        static const Enum<handlerTypes> handlerNames;
+
+
     // Constructors
 
         //- Construct from title string

src/OpenFOAM/db/functionObjects/functionObjectList/functionObjectList.C

@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2015-2022 OpenCFD Ltd.
+    Copyright (C) 2015-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -44,7 +44,7 @@ License
 /* * * * * * * * * * * * * * * Static Member Data  * * * * * * * * * * * * * */
 
 //- Max number of warnings (per functionObject)
-static constexpr const uint32_t maxWarnings = 10u;
+static constexpr const unsigned maxWarnings = 10u;
 
 Foam::fileName Foam::functionObjectList::functionObjectDictPath
 (
@@ -52,19 +52,6 @@ Foam::fileName Foam::functionObjectList::functionObjectDictPath
 );
 
 
-const Foam::Enum
-<
-    Foam::functionObjectList::errorHandlingType
->
-Foam::functionObjectList::errorHandlingNames_
-({
-    { errorHandlingType::DEFAULT, "default" },
-    { errorHandlingType::WARN, "warn" },
-    { errorHandlingType::IGNORE, "ignore" },
-    { errorHandlingType::STRICT, "strict" },
-});
-
-
 // * * * * * * * * * * * * * * * Local Functions * * * * * * * * * * * * * * //
 
 namespace Foam
@@ -350,12 +337,12 @@ bool Foam::functionObjectList::readFunctionObject
 }
 
 
-Foam::functionObjectList::errorHandlingType
+Foam::error::handlerTypes
 Foam::functionObjectList::getOrDefaultErrorHandling
 (
     const word& key,
     const dictionary& dict,
-    const errorHandlingType deflt
+    const error::handlerTypes deflt
 ) const
 {
     const entry* eptr = dict.findEntry(key, keyType::LITERAL);
@@ -372,16 +359,16 @@ Foam::functionObjectList::getOrDefaultErrorHandling
         {
             const word enumName(eptr->get<word>());
 
-            if (!errorHandlingNames_.found(enumName))
+            if (!error::handlerNames.found(enumName))
             {
                 // Failed the name lookup
                 FatalIOErrorInFunction(dict)
                     << enumName << " is not in enumeration: "
-                    << errorHandlingNames_ << nl
+                    << error::handlerNames << nl
                     << exit(FatalIOError);
             }
 
-            return errorHandlingNames_.get(enumName);
+            return error::handlerNames.get(enumName);
         }
     }
 
@@ -640,15 +627,15 @@ bool Foam::functionObjectList::execute()
 
         for (functionObject& funcObj : functions())
         {
-            const errorHandlingType errorHandling = *errIter;
+            const auto errorHandling = *errIter;
             ++errIter;
 
             const word& objName = funcObj.name();
 
             if
             (
-                errorHandling == errorHandlingType::WARN
-             || errorHandling == errorHandlingType::IGNORE
+                errorHandling == error::handlerTypes::WARN
+             || errorHandling == error::handlerTypes::IGNORE
             )
             {
                 // Throw FatalError, FatalIOError as exceptions
@@ -672,12 +659,12 @@ bool Foam::functionObjectList::execute()
                 catch (const Foam::error& err)
                 {
                     // Treat IOerror and error identically
-                    uint32_t nWarnings;
+                    unsigned nWarnings;
                     hadError = true;
 
                     if
                     (
-                        errorHandling != errorHandlingType::IGNORE
+                        (errorHandling != error::handlerTypes::IGNORE)
                      && (nWarnings = ++warnings_(objName)) <= maxWarnings
                     )
                     {
@@ -718,11 +705,11 @@ bool Foam::functionObjectList::execute()
                 catch (const Foam::error& err)
                 {
                     // Treat IOerror and error identically
-                    uint32_t nWarnings;
+                    unsigned nWarnings;
 
                     if
                     (
-                        errorHandling != errorHandlingType::IGNORE
+                        (errorHandling != error::handlerTypes::IGNORE)
                      && (nWarnings = ++warnings_(objName)) <= maxWarnings
                     )
                     {
@@ -851,7 +838,7 @@ bool Foam::functionObjectList::end()
 
         for (functionObject& funcObj : functions())
         {
-            const errorHandlingType errorHandling = *errIter;
+            const auto errorHandling = *errIter;
             ++errIter;
 
             const word& objName = funcObj.name();
@@ -870,11 +857,11 @@ bool Foam::functionObjectList::end()
             catch (const Foam::error& err)
             {
                 // Treat IOerror and error identically
-                uint32_t nWarnings;
+                unsigned nWarnings;
 
                 if
                 (
-                    errorHandling != errorHandlingType::IGNORE
+                    (errorHandling != error::handlerTypes::IGNORE)
                  && (nWarnings = ++warnings_(objName)) <= maxWarnings
                 )
                 {
@@ -982,7 +969,7 @@ bool Foam::functionObjectList::read()
         errorHandling_.resize
         (
             functionsDict.size(),
-            errorHandlingType::DEFAULT
+            error::handlerTypes::DEFAULT
         );
 
         HashTable<label> newIndices;
@@ -998,12 +985,12 @@ bool Foam::functionObjectList::read()
         );
 
         // Top-level "errors" specification (optional)
-        const errorHandlingType errorHandlingFallback =
+        const error::handlerTypes errorHandlingFallback =
             getOrDefaultErrorHandling
             (
                 "errors",
                 functionsDict,
-                errorHandlingType::DEFAULT
+                error::handlerTypes::DEFAULT
             );
 
         label nFunc = 0;
@@ -1045,7 +1032,7 @@ bool Foam::functionObjectList::read()
             bool enabled = dict.getOrDefault("enabled", true);
 
             // Per-function "errors" specification
-            const errorHandlingType errorHandling =
+            const error::handlerTypes errorHandling =
                 getOrDefaultErrorHandling
                 (
                     "errors",
@@ -1135,16 +1122,16 @@ bool Foam::functionObjectList::read()
 
                     switch (errorHandling)
                     {
-                        case errorHandlingType::IGNORE:
+                        case error::handlerTypes::IGNORE:
                             break;
 
-                        case errorHandlingType::STRICT:
+                        case error::handlerTypes::STRICT:
                         {
                             exitNow(err);
                             break;
                         }
 
-                        case errorHandlingType::DEFAULT:
+                        case error::handlerTypes::DEFAULT:
                         {
                             if (isA<Foam::IOerror>(err))
                             {
@@ -1157,7 +1144,7 @@ bool Foam::functionObjectList::read()
                             [[fallthrough]];
                         }
 
-                        case errorHandlingType::WARN:
+                        case error::handlerTypes::WARN:
                         {
                             // Trickery to get original message
                             err.write(Warning, false);

src/OpenFOAM/db/functionObjects/functionObjectList/functionObjectList.H

@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2015-2021 OpenCFD Ltd.
+    Copyright (C) 2015-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -78,11 +78,10 @@ SourceFiles
 
 \*---------------------------------------------------------------------------*/
 
-#ifndef functionObjectList_H
-#define functionObjectList_H
+#ifndef Foam_functionObjectList_H
+#define Foam_functionObjectList_H
 
 #include "PtrList.H"
-#include "Enum.H"
 #include "functionObject.H"
 #include "SHA1Digest.H"
 #include "HashTable.H"
@@ -108,25 +107,10 @@ class functionObjectList
 :
     private PtrList<functionObject>
 {
-    // Data Types
-
-        //- Handling of construction or execution errors
-        enum class errorHandlingType : uint8_t
-        {
-            DEFAULT = 0,  //!< Warn on construct, Fatal on runtime
-            WARN,         //!< Warn on construct, Warn on runtime
-            IGNORE,       //!< Ignore on construct, Ignore on runtime
-            STRICT,       //!< Fatal on construct, Fatal on runtime
-        };
-
-        //- Names for error handling types
-        static const Enum<errorHandlingType> errorHandlingNames_;
-
-
     // Private Data
 
         //- A list of error/warning handling
-        List<errorHandlingType> errorHandling_;
+        List<error::handlerTypes> errorHandling_;
 
         //- A list of SHA1 digests for the function object dictionaries
         List<SHA1Digest> digests_;
@@ -137,7 +121,7 @@ class functionObjectList
         //- Track the number of warnings per function object and limit
         //  to a predefined number to avoid flooding the display.
         //  Clear on re-read of functions.
-        HashTable<uint32_t> warnings_;
+        HashTable<unsigned> warnings_;
 
         //- Reference to Time
         const Time& time_;
@@ -187,11 +171,11 @@ class functionObjectList
         //
         //  This additional treatment is to ensure that potentially existing
         //  code with an "errors" functionObject will continue to run.
-        errorHandlingType getOrDefaultErrorHandling
+        error::handlerTypes getOrDefaultErrorHandling
         (
             const word& key,
             const dictionary& dict,
-            const errorHandlingType deflt
+            const error::handlerTypes deflt
         ) const;
 
 

src/OpenFOAM/global/fileOperations/fileOperation/fileOperationBroadcast.C

@@ -73,7 +73,11 @@ static void broadcastFile_single
     if (UPstream::master(comm))
     {
         // Read (see newIFstream)
-        lengthAndMode.first() = Foam::fileSize(srcName);
+        auto fileLen = Foam::fileSize(srcName);
+        if (fileLen > 0)
+        {
+            lengthAndMode.first() = uint64_t(fileLen);
+        }
         lengthAndMode.second() = Foam::mode(srcName);
 
         srcStream.reset

src/OpenFOAM/global/fileOperations/masterUncollatedFileOperation/masterUncollatedFileOperation.C

@@ -33,7 +33,7 @@ License
 #include "Time.H"
 #include "instant.H"
 #include "IFstream.H"
-#include "IListStream.H"
+#include "SpanStream.H"
 #include "masterOFstream.H"
 #include "decomposedBlockData.H"
 #include "registerSwitch.H"
@@ -83,6 +83,101 @@ namespace fileOperations
 }
 
 
+// * * * * * * * * * * * * * * * Local Functions * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+
+// Get file contents (compressed or uncompressed)
+static DynamicList<char> slurpFile(IFstream& ifs)
+{
+    DynamicList<char> buffer;
+
+    auto& iss = ifs.stdStream();
+
+    const auto inputSize = ifs.fileSize();
+
+    if (IOstreamOption::COMPRESSED == ifs.compression())
+    {
+        // For compressed files, no idea how large the result will be.
+        // So read chunk-wise.
+        // Using the compressed size for the chunk size:
+        // 50% compression = 2 iterations
+        // 66% compression = 3 iterations
+        // ...
+
+        const uint64_t chunkSize =
+        (
+            (inputSize <= 1024)
+          ? uint64_t(4096)
+          : uint64_t(2*inputSize)
+        );
+
+        uint64_t beg = 0;
+
+        for (int iter = 1; iter < 100000; ++iter)
+        {
+            // Manual resizing to use incremental vs doubling
+            buffer.setCapacity(label(iter * chunkSize));
+            buffer.resize(buffer.capacity());
+
+            ifs.readRaw(buffer.data() + beg, chunkSize);
+            const std::streamsize nread = iss.gcount();
+
+            if
+            (
+                nread < 0
+             || nread == std::numeric_limits<std::streamsize>::max()
+            )
+            {
+                // Failed, but treat as normal 'done'
+                buffer.resize(label(beg));
+                break;
+            }
+            else
+            {
+                beg += uint64_t(nread);
+                if (nread >= 0 && uint64_t(nread) < chunkSize)
+                {
+                    // normalExit = true;
+                    buffer.resize(label(beg));
+                    break;
+                }
+            }
+        }
+    }
+    else
+    {
+        if (inputSize >= 0)
+        {
+            buffer.setCapacity(label(inputSize));
+            buffer.resize(buffer.capacity());
+
+            ifs.readRaw(buffer.data(), buffer.size_bytes());
+            const std::streamsize nread = iss.gcount();
+
+            if
+            (
+                nread < 0
+             || nread == std::numeric_limits<std::streamsize>::max()
+            )
+            {
+                // Failed, but treat as normal 'done'
+                buffer.clear();
+            }
+            else
+            {
+                buffer.resize(label(nread));  // Safety
+            }
+        }
+    }
+
+    return buffer;
+}
+
+} // End namespace Foam
+
+
 // * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
 
 Foam::word
@@ -447,56 +542,25 @@ void Foam::fileOperations::masterUncollatedFileOperation::readAndSend
 
     if (debug)
     {
-        Pout<< "masterUncollatedFileOperation::readAndSend :"
+        Info<< "masterUncollatedFileOperation::readAndSend :"
             << " compressed:" << bool(ifs.compression()) << " "
             << filePath << endl;
     }
 
-    if (ifs.compression() == IOstreamOption::COMPRESSED)
+    // Read file contents (compressed or uncompressed) into a character buffer
+    DynamicList<char> buf(slurpFile(ifs));
+
+    for (const label proci : recvProcs)
     {
-        // Could use Foam::fileSize, estimate uncompressed size (eg, 2x)
-        // and then string reserve followed by string assign...
-
-        // Uncompress and read file contents into a character buffer
-        const std::string buf
-        (
-            std::istreambuf_iterator<char>(ifs.stdStream()),
-            std::istreambuf_iterator<char>()
-        );
-
-        for (const label proci : recvProcs)
-        {
-            UOPstream os(proci, pBufs);
-            os.write(buf.data(), buf.length());
-        }
-
-        if (debug)
-        {
-            Pout<< "masterUncollatedFileOperation::readStream :"
-                << " From " << filePath <<  " sent " << buf.size()
-                << " bytes" << endl;
-        }
+        UOPstream os(proci, pBufs);
+        os.write(buf.cdata_bytes(), buf.size_bytes());
     }
-    else
+
+    if (debug)
     {
-        const off_t count(Foam::fileSize(filePath));
-
-        // Read file contents into a character buffer
-        List<char> buf(static_cast<label>(count));
-        ifs.stdStream().read(buf.data(), count);
-
-        for (const label proci : recvProcs)
-        {
-            UOPstream os(proci, pBufs);
-            os.write(buf.cdata(), count);
-        }
-
-        if (debug)
-        {
-            Pout<< "masterUncollatedFileOperation::readStream :"
-                << " From " << filePath <<  " sent " << buf.size()
-                << " bytes" << endl;
-        }
+        Info<< "masterUncollatedFileOperation::readStream :"
+            << " From " << filePath <<  " sent " << buf.size()
+            << " bytes" << endl;
     }
 }
 
@@ -630,7 +694,7 @@ Foam::fileOperations::masterUncollatedFileOperation::read
             // Construct with same parameters (ASCII, current version)
             // as the IFstream so that it has the same characteristics.
 
-            isPtr.reset(new IListStream(std::move(buf)));
+            isPtr.reset(new ICharStream(std::move(buf)));
 
             // With the proper file name
             isPtr->name() = filePaths[UPstream::myProcNo(comm)];
@@ -2493,7 +2557,7 @@ Foam::fileOperations::masterUncollatedFileOperation::NewIFstream
             // Construct with same parameters (ASCII, current version)
             // as the IFstream so that it has the same characteristics.
 
-            isPtr.reset(new IListStream(std::move(buf)));
+            isPtr.reset(new ICharStream(std::move(buf)));
 
             // With the proper file name
             isPtr->name() = filePath;

src/fileFormats/abaqus/ABAQUSCore.C

@@ -29,7 +29,7 @@ License
 #include "IFstream.H"
 #include "ListOps.H"
 #include "stringOps.H"
-#include "UIListStream.H"
+#include "SpanStream.H"
 #include "cellModel.H"
 #include <cctype>
 
@@ -328,15 +328,15 @@ Foam::fileFormats::ABAQUSCore::readHelper::readPoints
     // Read nodes (points) until next "*Section"
     while (is.peek() != '*' && is.peek() != EOF)
     {
-        // Grab the line and wrap as string-stream
+        // Grab the line and wrap as spanstream
         is.getLine(line);
-        UIListStream ss(line.data(), line.length());
 
         if (line.empty())
         {
             // Not sure if we should terminate on blank lines?
             continue;
         }
+        ISpanStream ss(line);
 
         // Parse line for ID, X, Y, Z
         ss >> id >> sep >> p.x() >> sep >> p.y() >> sep >> p.z();

src/fileFormats/ensight/read/ensightReadFile.C

@@ -50,12 +50,10 @@ Foam::ensightReadFile::detectBinaryHeader(const fileName& pathname)
         // Binary string is *exactly* 80 characters
         string buf(size_t(80), '\0');
         iss.read(&buf[0], 80);
+        const std::streamsize gcount = iss.gcount();
+        buf.erase(gcount <= 0 ? 0 : gcount);  // Truncated?
 
-        if (!iss)
-        {
-            // Truncated?
-            buf.erase(iss.gcount());
-        }
+        // Could exit on truncated input, but no real advantage
 
         // Truncate at the first embedded '\0'
         const auto endp = buf.find('\0');
@@ -119,15 +117,13 @@ Foam::Istream& Foam::ensightReadFile::read(string& value)
         // Binary string is *exactly* 80 characters
         value.resize(80, '\0');
         iss.read(&value[0], 80);
+        const std::streamsize gcount = iss.gcount();
+        value.erase(gcount <= 0 ? 0 : gcount);  // Truncated?
+
+        // Could exit on truncated input, but no real advantage
 
         syncState();
 
-        if (!iss)
-        {
-            // Truncated - could also exit here, but no real advantage
-            value.erase(iss.gcount());
-        }
-
         // Truncate at the first embedded '\0'
         auto endp = value.find('\0');
 

src/fileFormats/stl/STLAsciiParse.H

@@ -112,8 +112,8 @@ public:
 
     // Constructors
 
-        //- From input stream and the approximate number of vertices in the STL
-        inline STLAsciiParse(const label approxNpoints);
+        //- Construct with the estimated number of triangles in the STL
+        inline STLAsciiParse(const label nTrisEstimated);
 
 
     // Member Functions

src/fileFormats/stl/STLAsciiParseFlex.L

@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2016-2018 OpenCFD Ltd.
+    Copyright (C) 2016-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -89,10 +89,10 @@ public:
 
     // Constructors
 
-    //- From input stream and the approximate number of vertices in the STL
-    STLAsciiParseFlex(istream* is, const label approxNpoints)
+    //- From input stream, with the estimated number of triangles in the STL
+    STLAsciiParseFlex(istream* is, const label nTrisEstimated)
     :
-        Detail::STLAsciiParse(approxNpoints),
+        Detail::STLAsciiParse(nTrisEstimated),
         yySTLFlexLexer(is)
     {}
 
@@ -306,9 +306,8 @@ endsolid              {space}("endsolid"|"ENDSOLID")({some_space}{word})*
 %%
 
 
-//
-// Member Function
-//
+// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
+
 bool Foam::fileFormats::STLReader::readAsciiFlex
 (
     const fileName& filename
@@ -322,8 +321,20 @@ bool Foam::fileFormats::STLReader::readAsciiFlex
             << exit(FatalError);
     }
 
-    // Create with approx number of vertices in the STL (from file size)
-    STLAsciiParseFlex lexer(&(is.stdStream()), Foam::fileSize(filename)/400);
+    // Create with estimated number of triangles in the STL.
+    // 180 bytes / triangle. For simplicity, ignore compression
+
+    const auto fileLen = is.fileSize();
+
+    const label nTrisEstimated =
+    (
+        (fileLen > 0)
+      ? max(label(100), label(fileLen/180))
+      : label(100)
+    );
+
+
+    STLAsciiParseFlex lexer(&(is.stdStream()), nTrisEstimated);
     lexer.execute();
 
     transfer(lexer);
@@ -331,6 +342,5 @@ bool Foam::fileFormats::STLReader::readAsciiFlex
     return true;
 }
 
- /* ------------------------------------------------------------------------ *\
-    ------ End of STLReaderASCII.L
- \* ------------------------------------------------------------------------ */
+
+// ************************************************************************* //

src/fileFormats/stl/STLAsciiParseI.H

@@ -131,15 +131,15 @@ inline void Foam::Detail::STLAsciiParse::endFacet()
 
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
-inline Foam::Detail::STLAsciiParse::STLAsciiParse(const label approxNpoints)
+inline Foam::Detail::STLAsciiParse::STLAsciiParse(const label nTrisEstimated)
 :
     sorted_(true),
     groupId_(-1),
     lineNum_(1),
     nFacetPoints_(0),
     nVertexCmpt_(0),
-    points_(approxNpoints),
-    facets_(approxNpoints/2)
+    points_(3*nTrisEstimated),
+    facets_(nTrisEstimated)
 {}
 
 

src/fileFormats/stl/STLAsciiParseManual.C

@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2018 OpenCFD Ltd.
+    Copyright (C) 2018-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -30,7 +30,6 @@ Description
 
 #include "STLAsciiParse.H"
 #include "STLReader.H"
-#include "OSspecific.H"
 #include "stringOps.H"
 
 // * * * * * * * * * * * * * * * Local Functions * * * * * * * * * * * * * * //
@@ -127,10 +126,10 @@ class STLAsciiParseManual
 
 public:
 
-    //- From input stream and the approximate number of vertices in the STL
-    STLAsciiParseManual(const label approxNpoints)
+    //- Construct with the estimated number of triangles in the STL
+    STLAsciiParseManual(const label nTrisEstimated)
     :
-        Detail::STLAsciiParse(approxNpoints)
+        Detail::STLAsciiParse(nTrisEstimated)
     {}
 
     //- Execute parser
@@ -179,7 +178,7 @@ void Foam::Detail::STLAsciiParseManual::execute(std::istream& is)
         is.read(data, buflen);
         const std::streamsize gcount = is.gcount();
 
-        if (!gcount)
+        if (gcount <= 0)
         {
             // EOF
             // If scanning for next "solid" this is a valid way to exit, but
@@ -398,11 +397,8 @@ void Foam::Detail::STLAsciiParseManual::execute(std::istream& is)
 }
 
 
-/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
-//
-// Member Function
-//
 bool Foam::fileFormats::STLReader::readAsciiManual
 (
     const fileName& filename
@@ -416,8 +412,20 @@ bool Foam::fileFormats::STLReader::readAsciiManual
             << exit(FatalError);
     }
 
-    // Create with the approximate number of vertices in the STL from file size
-    Detail::STLAsciiParseManual lexer(Foam::fileSize(filename)/400);
+    // Create with estimated number of triangles in the STL.
+    // 180 bytes / triangle. For simplicity, ignore compression
+
+    const auto fileLen = is.fileSize();
+
+    const label nTrisEstimated =
+    (
+        (fileLen > 0)
+      ? max(label(100), label(fileLen/180))
+      : label(100)
+    );
+
+
+    Detail::STLAsciiParseManual lexer(nTrisEstimated);
     lexer.execute(is.stdStream());
 
     transfer(lexer);

src/fileFormats/stl/STLAsciiParseRagel.cc

@@ -7,7 +7,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2018 OpenCFD Ltd.
+    Copyright (C) 2018-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -35,7 +35,6 @@ Description
 
 #include "STLAsciiParse.H"
 #include "STLReader.H"
-#include "OSspecific.H"
 
 #pragma GCC diagnostic ignored "-Wimplicit-fallthrough"
 #pragma GCC diagnostic ignored "-Wunused-const-variable"
@@ -69,6 +68,7 @@ Description
 // - Only look for initial 'facet '. Ignore 'normal ...'
 // - Ignore name for 'endsolid'
 //
+// ------------------------------------------------------------------------- //
 
 // Ragel machine definition
 // Ragel variables (p, pe, eof, cs, top, stack, ts, te, act) defined later...
@@ -121,10 +121,10 @@ class STLAsciiParseRagel
 
 public:
 
-    //- From input stream and the approximate number of vertices in the STL
-    STLAsciiParseRagel(const label approxNpoints)
+    //- From input stream, with the estimated number of triangles in the STL
+    STLAsciiParseRagel(const label nTrisEstimated)
     :
-        Detail::STLAsciiParse(approxNpoints)
+        Detail::STLAsciiParse(nTrisEstimated)
     {}
 
     //- Execute lexer
@@ -184,7 +184,7 @@ void Foam::Detail::STLAsciiParseRagel::execute(std::istream& is)
 
         is.read(data, buflen);
         const std::streamsize gcount = is.gcount();
-        if (!gcount)
+        if (gcount <= 0)
         {
             break;
         }
@@ -2970,9 +2970,7 @@ void Foam::Detail::STLAsciiParseRagel::die
     const char *pe
 ) const
 {
-    auto error = FatalErrorInFunction;
-
-    error
+    FatalErrorInFunction
         << nl
         << "Parsing error at or near line " << lineNum_
         <<", while parsing for " << what << nl
@@ -2984,22 +2982,19 @@ void Foam::Detail::STLAsciiParseRagel::die
         for (unsigned i=0; i < 80; ++i)
         {
             if (*parsing == '\n' || parsing == pe) break;
-            error << *parsing;
+            FatalError << *parsing;
             ++parsing;
         }
     }
 
-    error
+    FatalError
         << "'\n"
         << exit(FatalError);
 }
 
 
-/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
-//
-// Member Function
-//
 bool Foam::fileFormats::STLReader::readAsciiRagel
 (
     const fileName& filename
@@ -3013,8 +3008,20 @@ bool Foam::fileFormats::STLReader::readAsciiRagel
             << exit(FatalError);
     }
 
-    // Create with approx number of vertices in the STL (from file size)
-    Detail::STLAsciiParseRagel lexer(Foam::fileSize(filename)/400);
+    // Create with estimated number of triangles in the STL.
+    // 180 bytes / triangle. For simplicity, ignore compression
+
+    const auto fileLen = is.fileSize();
+
+    const label nTrisEstimated =
+    (
+        (fileLen > 0)
+      ? max(label(100), label(fileLen/180))
+      : label(100)
+    );
+
+
+    Detail::STLAsciiParseRagel lexer(nTrisEstimated);
     lexer.execute(is.stdStream());
 
     transfer(lexer);

src/fileFormats/stl/STLAsciiParseRagel.rl

@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2018 OpenCFD Ltd.
+    Copyright (C) 2018-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -33,7 +33,6 @@ Description
 
 #include "STLAsciiParse.H"
 #include "STLReader.H"
-#include "OSspecific.H"
 
 #pragma GCC diagnostic ignored "-Wimplicit-fallthrough"
 #pragma GCC diagnostic ignored "-Wunused-const-variable"
@@ -67,6 +66,7 @@ Description
 // - Only look for initial 'facet '. Ignore 'normal ...'
 // - Ignore name for 'endsolid'
 //
+// ------------------------------------------------------------------------- //
 
 // Ragel machine definition
 // Ragel variables (p, pe, eof, cs, top, stack, ts, te, act) defined later...
@@ -176,10 +176,10 @@ class STLAsciiParseRagel
 
 public:
 
-    //- From input stream and the approximate number of vertices in the STL
-    STLAsciiParseRagel(const label approxNpoints)
+    //- From input stream, with the estimated number of triangles in the STL
+    STLAsciiParseRagel(const label nTrisEstimated)
     :
-        Detail::STLAsciiParse(approxNpoints)
+        Detail::STLAsciiParse(nTrisEstimated)
     {}
 
     //- Execute lexer
@@ -232,7 +232,7 @@ void Foam::Detail::STLAsciiParseRagel::execute(std::istream& is)
 
         is.read(data, buflen);
         const std::streamsize gcount = is.gcount();
-        if (!gcount)
+        if (gcount <= 0)
         {
             break;
         }
@@ -303,9 +303,7 @@ void Foam::Detail::STLAsciiParseRagel::die
     const char *pe
 ) const
 {
-    auto error = FatalErrorInFunction;
-
-    error
+    FatalErrorInFunction
         << nl
         << "Parsing error at or near line " << lineNum_
         <<", while parsing for " << what << nl
@@ -317,22 +315,19 @@ void Foam::Detail::STLAsciiParseRagel::die
         for (unsigned i=0; i < 80; ++i)
         {
             if (*parsing == '\n' || parsing == pe) break;
-            error << *parsing;
+            FatalError << *parsing;
             ++parsing;
         }
     }
 
-    error
+    FatalError
         << "'\n"
         << exit(FatalError);
 }
 
 
-/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
-//
-// Member Function
-//
 bool Foam::fileFormats::STLReader::readAsciiRagel
 (
     const fileName& filename
@@ -346,8 +341,20 @@ bool Foam::fileFormats::STLReader::readAsciiRagel
             << exit(FatalError);
     }
 
-    // Create with approx number of vertices in the STL (from file size)
-    Detail::STLAsciiParseRagel lexer(Foam::fileSize(filename)/400);
+    // Create with estimated number of triangles in the STL.
+    // 180 bytes / triangle. For simplicity, ignore compression
+
+    const auto fileLen = is.fileSize();
+
+    const label nTrisEstimated =
+    (
+        (fileLen > 0)
+      ? max(label(100), label(fileLen/180))
+      : label(100)
+    );
+
+
+    Detail::STLAsciiParseRagel lexer(nTrisEstimated);
     lexer.execute(is.stdStream());
 
     transfer(lexer);

src/fileFormats/vtk/file/foamVtkSeriesWriter.C

@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2018-2022 OpenCFD Ltd.
+    Copyright (C) 2018-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -645,7 +645,8 @@ Foam::label Foam::vtk::seriesWriter::scan
 
         header.resize(1024);
         is.read(&(header.front()), header.size());
-        header.resize(is.gcount());
+        const std::streamsize gcount = is.gcount();
+        header.erase(gcount <= 0 ? 0 : gcount);
 
         // DebugInfo
         //     << "got header:\n=====\n" << header << "\n=====\n" << nl;

src/functionObjects/field/fieldValues/surfaceFieldValue/surfaceFieldValue.C

@@ -37,6 +37,9 @@ License
 
 // * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
 
+// Max number of warnings
+static constexpr const unsigned maxWarnings = 10u;
+
 namespace Foam
 {
 namespace functionObjects
@@ -135,39 +138,13 @@ void Foam::functionObjects::fieldValues::surfaceFieldValue::setFaceZoneFaces()
         mesh_.faceZones().indices(selectionNames_)
     );
 
-    // Total number of faces selected
+    // Total number of faces that could be selected (before patch filtering)
     label numFaces = 0;
     for (const label zoneId : zoneIds)
     {
         numFaces += mesh_.faceZones()[zoneId].size();
     }
 
-    if (zoneIds.empty())
-    {
-        FatalErrorInFunction
-            << type() << ' ' << name() << ": "
-            << regionTypeNames_[regionType_] << '(' << regionName_ << "):" << nl
-            << "    No matching face zone(s): "
-            << flatOutput(selectionNames_)  << nl
-            << "    Known face zones: "
-            << flatOutput(mesh_.faceZones().names()) << nl
-            << exit(FatalError);
-    }
-
-    // Could also check this
-    #if 0
-    if (!returnReduceOr(numFaces))
-    {
-        WarningInFunction
-            << type() << ' ' << name() << ": "
-            << regionTypeNames_[regionType_] << '(' << regionName_ << "):" << nl
-            << "    The faceZone specification: "
-            << flatOutput(selectionNames_) << nl
-            << "    resulted in 0 faces" << nl
-            << exit(FatalError);
-    }
-    #endif
-
     faceId_.resize_nocopy(numFaces);
     facePatchId_.resize_nocopy(numFaces);
     faceFlip_.resize_nocopy(numFaces);
@@ -223,7 +200,75 @@ void Foam::functionObjects::fieldValues::surfaceFieldValue::setFaceZoneFaces()
     faceId_.resize(numFaces);
     facePatchId_.resize(numFaces);
     faceFlip_.resize(numFaces);
-    nFaces_ = returnReduce(faceId_.size(), sumOp<label>());
+    nFaces_ = returnReduce(numFaces, sumOp<label>());
+
+    if (!nFaces_)
+    {
+        // Raise warning or error
+        refPtr<OSstream> os;
+        bool fatal = false;
+
+        ++nWarnings_;  // Always increment (even if ignore etc)
+
+        switch (emptySurfaceError_)
+        {
+            case error::handlerTypes::IGNORE:
+            {
+                break;
+            }
+
+            case error::handlerTypes::WARN:
+            {
+                if (nWarnings_ <= maxWarnings)
+                {
+                    os.ref(WarningInFunction);
+                }
+                break;
+            }
+
+            // STRICT / DEFAULT
+            default:
+            {
+                os.ref(FatalErrorInFunction);
+                fatal = true;
+                break;
+            }
+        }
+
+        if (os)
+        {
+            os.ref()
+                << type() << ' ' << name() << ": "
+                << regionTypeNames_[regionType_]
+                << '(' << regionName_ << "):" << nl;
+
+            if (zoneIds.empty())
+            {
+                os.ref()
+                    << "    No matching face zones: "
+                    << flatOutput(selectionNames_)  << nl
+                    << "    Known face zones: "
+                    << flatOutput(mesh_.faceZones().names()) << nl;
+            }
+            else
+            {
+                os.ref()
+                    << "    The face zones: "
+                    << flatOutput(selectionNames_) << nl
+                    << "    resulted in 0 faces" << nl;
+            }
+
+            if (fatal)
+            {
+                FatalError<< exit(FatalError);
+            }
+            else if (nWarnings_ == maxWarnings)
+            {
+                os.ref()
+                    << "... suppressing further warnings." << nl;
+            }
+        }
+    }
 }
 
 
@@ -283,7 +328,7 @@ void Foam::functionObjects::fieldValues::surfaceFieldValue::setPatchFaces()
         nGood = 0;
         for (const label patchi : selected)
         {
-            if (!bad.found(patchi))
+            if (!bad.contains(patchi))
             {
                 patchIds[nGood] = patchi;
                 ++nGood;
@@ -295,36 +340,10 @@ void Foam::functionObjects::fieldValues::surfaceFieldValue::setPatchFaces()
         patchIds = std::move(selected);
     }
 
-    if (patchIds.empty())
-    {
-        FatalErrorInFunction
-            << type() << ' ' << name() << ": "
-            << regionTypeNames_[regionType_] << '(' << regionName_ << "):" << nl
-            << "    No matching patch name(s): "
-            << flatOutput(selectionNames_)  << nl
-            << "    Known patch names:" << nl
-            << mesh_.boundaryMesh().names() << nl
-            << exit(FatalError);
-    }
-
-    // Could also check this
-    #if 0
-    if (!returnReduceOr(numFaces))
-    {
-        WarningInFunction
-            << type() << ' ' << name() << ": "
-            << regionTypeNames_[regionType_] << '(' << regionName_ << "):" << nl
-            << "    The patch specification: "
-            << flatOutput(selectionNames_) << nl
-            << "    resulted in 0 faces" << nl
-            << exit(FatalError);
-    }
-    #endif
-
-    faceId_.resize(numFaces);
-    facePatchId_.resize(numFaces);
-    faceFlip_.resize(numFaces);
-    nFaces_ = returnReduce(faceId_.size(), sumOp<label>());
+    faceId_.resize_nocopy(numFaces);
+    facePatchId_.resize_nocopy(numFaces);
+    faceFlip_.resize_nocopy(numFaces);
+    nFaces_ = returnReduce(numFaces, sumOp<label>());
 
     numFaces = 0;
     for (const label patchi : patchIds)
@@ -338,6 +357,74 @@ void Foam::functionObjects::fieldValues::surfaceFieldValue::setPatchFaces()
 
         numFaces += len;
     }
+
+    if (!nFaces_)
+    {
+        // Raise warning or error
+        refPtr<OSstream> os;
+        bool fatal = false;
+
+        ++nWarnings_;  // Always increment (even if ignore etc)
+
+        switch (emptySurfaceError_)
+        {
+            case error::handlerTypes::IGNORE:
+            {
+                break;
+            }
+
+            case error::handlerTypes::WARN:
+            {
+                if (nWarnings_ <= maxWarnings)
+                {
+                    os.ref(WarningInFunction);
+                }
+                break;
+            }
+
+            // STRICT / DEFAULT
+            default:
+            {
+                os.ref(FatalErrorInFunction);
+                fatal = true;
+                break;
+            }
+        }
+
+        if (os)
+        {
+            os.ref()
+                << type() << ' ' << name() << ": "
+                << regionTypeNames_[regionType_]
+                << '(' << regionName_ << "):" << nl;
+
+            if (patchIds.empty())
+            {
+                os.ref()
+                    << "    No matching patches: "
+                    << flatOutput(selectionNames_)  << nl
+                    << "    Known patch names:" << nl
+                    << mesh_.boundaryMesh().names() << nl;
+            }
+            else
+            {
+                os.ref()
+                    << "    The patches: "
+                    << flatOutput(selectionNames_) << nl
+                    << "    resulted in 0 faces" << nl;
+            }
+
+            if (fatal)
+            {
+                FatalError<< exit(FatalError);
+            }
+            else if (nWarnings_ == maxWarnings)
+            {
+                os.ref()
+                    << "... suppressing further warnings." << nl;
+            }
+        }
+    }
 }
 
 
@@ -511,20 +598,30 @@ bool Foam::functionObjects::fieldValues::surfaceFieldValue::update()
         return false;
     }
 
+    // Reset some values
+    totalArea_ = 0;
+    nFaces_ = 0;
+    bool checkEmptyFaces = true;
+
     switch (regionType_)
     {
         case stFaceZone:
         {
+            // Raises warning or error internally, don't check again
             setFaceZoneFaces();
+            checkEmptyFaces = false;
             break;
         }
         case stPatch:
         {
+            // Raises warning or error internally, don't check again
             setPatchFaces();
+            checkEmptyFaces = false;
             break;
         }
         case stObject:
         {
+            // TBD: special handling of cast errors?
             const auto& s = refCast<const polySurface>(obr());
             nFaces_ = returnReduce(s.size(), sumOp<label>());
             break;
@@ -538,23 +635,76 @@ bool Foam::functionObjects::fieldValues::surfaceFieldValue::update()
         // Compiler warning if we forgot an enumeration
     }
 
-    if (nFaces_ == 0)
+    if (nFaces_)
     {
-        FatalErrorInFunction
-            << type() << ' ' << name() << ": "
-            << regionTypeNames_[regionType_] << '(' << regionName_ << "):" << nl
-            << "    Region has no faces" << exit(FatalError);
+        // Appears to be successful
+        needsUpdate_ = false;
+        totalArea_ = totalArea();   // Update the area
+        nWarnings_ = 0u;            // Reset the warnings counter
     }
+    else if (checkEmptyFaces)
+    {
+        // Raise warning or error
+        refPtr<OSstream> os;
+        bool fatal = false;
 
-    totalArea_ = totalArea();
+        ++nWarnings_;  // Always increment (even if ignore etc)
+
+        switch (emptySurfaceError_)
+        {
+            case error::handlerTypes::IGNORE:
+            {
+                break;
+            }
+
+            case error::handlerTypes::WARN:
+            {
+                if (nWarnings_ <= maxWarnings)
+                {
+                    os.ref(WarningInFunction);
+                }
+                break;
+            }
+
+            // STRICT / DEFAULT
+            default:
+            {
+                os.ref(FatalErrorInFunction);
+                fatal = true;
+                break;
+            }
+        }
+
+        if (os)
+        {
+            os.ref()
+                << type() << ' ' << name() << ": "
+                << regionTypeNames_[regionType_]
+                << '(' << regionName_ << "):" << nl
+                << "    Region has no faces" << endl;
+
+            if (fatal)
+            {
+                FatalError<< exit(FatalError);
+            }
+            else if (nWarnings_ == maxWarnings)
+            {
+                os.ref()
+                    << "... suppressing further warnings." << nl;
+            }
+        }
+    }
 
     Log << "    total faces   = " << nFaces_ << nl
         << "    total area    = " << totalArea_ << nl
         << endl;
 
-    writeFileHeader(file());
+    // Emit file header on success or change of state
+    if (nWarnings_ <= 1)
+    {
+        writeFileHeader(file());
+    }
 
-    needsUpdate_ = false;
     return true;
 }
 
@@ -931,10 +1081,12 @@ Foam::functionObjects::fieldValues::surfaceFieldValue::surfaceFieldValue
     ),
     needsUpdate_(true),
     writeArea_(false),
+    emptySurfaceError_(error::handlerTypes::DEFAULT),
     selectionNames_(),
     weightFieldNames_(),
     totalArea_(0),
     nFaces_(0),
+    nWarnings_(0),
     faceId_(),
     facePatchId_(),
     faceFlip_()
@@ -965,10 +1117,12 @@ Foam::functionObjects::fieldValues::surfaceFieldValue::surfaceFieldValue
     ),
     needsUpdate_(true),
     writeArea_(false),
+    emptySurfaceError_(error::handlerTypes::DEFAULT),
     selectionNames_(),
     weightFieldNames_(),
     totalArea_(0),
     nFaces_(0),
+    nWarnings_(0),
     faceId_(),
     facePatchId_(),
     faceFlip_()
@@ -995,12 +1149,21 @@ bool Foam::functionObjects::fieldValues::surfaceFieldValue::read
 
     needsUpdate_ = true;
     writeArea_ = dict.getOrDefault("writeArea", false);
+    emptySurfaceError_ = error::handlerNames.getOrDefault
+    (
+        "empty-surface",
+        dict,
+        error::handlerTypes::DEFAULT,
+        true  // Failsafe behaviour
+    );
+
     weightFieldNames_.clear();
     // future?
     // sampleFaceScheme_ = dict.getOrDefault<word>("sampleScheme", "cell");
 
     totalArea_ = 0;
     nFaces_ = 0;
+    nWarnings_ = 0;
     faceId_.clear();
     facePatchId_.clear();
     faceFlip_.clear();
@@ -1182,12 +1345,39 @@ bool Foam::functionObjects::fieldValues::surfaceFieldValue::write()
         writeCurrentTime(file());
     }
 
+    // Handle ignore/warn about empty-surface
+    if (!nFaces_)
+    {
+        totalArea_ = 0;  // Update the area (safety)
+
+        if (operation_ != opNone)
+        {
+            if (emptySurfaceError_ == error::handlerTypes::WARN)
+            {
+                if (writeArea_)
+                {
+                    Log << "    total area = " << totalArea_ << endl;
+                    file() << tab << totalArea_;
+                }
+
+                file() << tab << "NaN";
+                Log << endl;
+            }
+
+            file() << endl;
+        }
+
+        // Early exit on error
+        return true;
+    }
+
     if (writeArea_)
     {
+        // Update the area
         totalArea_ = totalArea();
         Log << "    total area = " << totalArea_ << endl;
 
-        if (operation_ != opNone && Pstream::master())
+        if (operation_ != opNone && UPstream::master())
         {
             file() << tab << totalArea_;
         }

src/functionObjects/field/fieldValues/surfaceFieldValue/surfaceFieldValue.H

@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2015-2020 OpenCFD Ltd.
+    Copyright (C) 2015-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -88,6 +88,7 @@ Usage
         scaleFactor     1.0;
         writeArea       false;
         surfaceFormat   none;
+        empty-surface   warn;  // default | warn | ignore | strict
 
         // Optional (inherited) entries
         ...
@@ -111,6 +112,7 @@ Usage
       writeArea    | Write the surface area             | bool |  no   | false
       surfaceFormat | Output value format               | word <!--
                 --> | conditional on writeFields  | none
+      empty-surface | Error handling for empty surfaces | enum | no | default
     \endtable
 
     The inherited entries are elaborated in:
@@ -400,6 +402,9 @@ protected:
         //- Optionally write the area of the surfaceFieldValue
         bool writeArea_;
 
+        //- Handling of empty surfaces (nFaces = 0). Default is Fatal.
+        error::handlerTypes emptySurfaceError_;
+
         //- Extended selections
         wordRes selectionNames_;
 
@@ -412,6 +417,9 @@ protected:
         //- Global number of faces
         label nFaces_;
 
+        //- Number of warnings emitted since the last valid update
+        unsigned nWarnings_;
+
 
     // If operating on mesh faces (faceZone, patch)
 

src/surfMesh/readers/ensight/ensightSurfaceReaderTemplates.C

@@ -25,7 +25,7 @@ License
 
 \*---------------------------------------------------------------------------*/
 
-#include "UIListStream.H"
+#include "SpanStream.H"
 #include "ensightPTraits.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
@@ -52,7 +52,7 @@ void Foam::ensightSurfaceReader::readFromLine
     Type& value
 ) const
 {
-    UIListStream is(buffer.data(), buffer.length());
+    ISpanStream is(buffer.data(), buffer.length());
 
     readFromLine(nSkip, is, value);
 }