ENH: cleanup and rationalize memory-backed streams

- more consistent naming:
  * Versions that hold and manage their own memory:
      IListStream, OListStream

  * Versions that reference a fixed size external memory:
      UIListStream, UOListStream

- use List storage instead of DynamicList within OListStream.
  Avoids duplicate bookkeeping, more direct handling of resizing.

applications/test/IListStream/Make/files

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

applications/test/IListStream/Make/options

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

applications/test/IListStream/Test-IListStream.C

@@ -0,0 +1,151 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2017 OpenCFD Ltd.
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+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
+
+\*---------------------------------------------------------------------------*/
+
+#include "ListStream.H"
+#include "UListStream.H"
+#include "wordList.H"
+#include "IOstreams.H"
+#include "argList.H"
+
+using namespace Foam;
+
+Ostream& toString(Ostream& os, const UList<char>& list)
+{
+    os << '"';
+    for (const char c : list)
+    {
+        os << c;
+    }
+    os << '"';
+
+    return os;
+}
+
+
+template<class BufType>
+void printInfo(const BufType& buf)
+{
+    Info<< nl << "=========================" << endl;
+    buf.print(Info);
+    toString(Info, buf.list());
+    Info<< nl << "=========================" << endl;
+}
+
+
+void printTokens(Istream& is)
+{
+    label count = 0;
+    token t;
+    while (is.good())
+    {
+        is >> t;
+        if (t.good())
+        {
+            ++count;
+            Info<<"token: " << t << endl;
+        }
+    }
+
+    Info<< count << " tokens" << endl;
+}
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+// Main program:
+
+int main(int argc, char *argv[])
+{
+    // Buffer storage
+    DynamicList<char> storage(16);
+
+    OListStream obuf(std::move(storage));
+    obuf << 1002 << " " << "abcd" << " " << "def" << " " << 3.14159 << ";\n";
+
+    // Move contents to output buffer
+    printInfo(obuf);
+
+    Info<<nl << "as string: ";
+    toString(Info, obuf.list()) << endl;
+
+    Info<< "transfer contents to a List" << endl;
+
+    IListStream ibuf(obuf.xfer());
+
+    Info<< nl;
+    Info<< nl << "input string:";
+    printInfo(ibuf);
+
+    Info<< nl << "orig output:";
+    printInfo(obuf);
+
+    printTokens(ibuf);
+
+    Info<<nl << "after:";
+    printInfo(ibuf);
+
+    // This should also work
+    ibuf.list() = 'X';
+
+    Info<<nl << "overwritten with const value:";
+    printInfo(ibuf);
+
+    // Can also change content like this:
+    {
+        const int n = min(26, ibuf.size());
+
+        for (int i=0; i<n; ++i)
+        {
+            ibuf.list()[i] = 'A' + i;
+        }
+    }
+
+    Info<<nl << "directly written:";
+    printInfo(ibuf);
+
+    // But cannot easily swap in/out an entirely new list storage:
+    //
+    // List<char> newvalues(52);
+    // {
+    //     for (int i=0; i<26; ++i)
+    //     {
+    //         newvalues[2*i+0] = char('a' + i);
+    //         newvalues[2*i+1] = char('A' + i);
+    //     }
+    // }
+    // ibuf.swap(newvalues);
+    //
+    // Info<<nl << "after swap:";
+    // printInfo(ibuf);
+
+
+    Info<< "\nEnd\n" << endl;
+
+    return 0;
+}
+
+
+// ************************************************************************* //

applications/test/OCountStream/Make/files

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

applications/test/OCountStream/Make/options

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

applications/test/OCountStream/Test-OCountStream.C

@@ -0,0 +1,61 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2017 OpenCFD Ltd.
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+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
+
+\*---------------------------------------------------------------------------*/
+
+#include "OCountStream.H"
+#include "StringStream.H"
+#include "IOstreams.H"
+#include "argList.H"
+
+using namespace Foam;
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+// Main program:
+
+int main(int argc, char *argv[])
+{
+    OCountStream cnt;
+    OStringStream str;
+
+    for (label i = 0; i < 50; ++i)
+    {
+        str << 1002 << " " << "abcd" << " "
+            << "def" << " " << 3.14159 << ";\n";
+
+        cnt << 1002 << " " << "abcd" << " "
+            << "def" << " " << 3.14159 << ";\n";
+    }
+
+    cnt.print(Info);
+    Info<< "via string-stream: " << str.str().size() << " chars" << endl;
+
+    Info<< "\nEnd\n" << endl;
+
+    return 0;
+}
+
+
+// ************************************************************************* //

applications/test/OListStream/Make/options

@@ -1,2 +1,2 @@
-/* EXE_INC = -I$(LIB_SRC)/finiteVolume/lnInclude */
+/* EXE_INC = */
-/* EXE_LIBS = -lfiniteVolume */
+/* EXE_LIBS = */

applications/test/OListStream/Test-OListStream.C

@@ -25,7 +25,7 @@ Description
 
 \*---------------------------------------------------------------------------*/
 
-#include "OListStream.H"
+#include "ListStream.H"
 #include "wordList.H"
 #include "IOstreams.H"
 #include "argList.H"
@@ -45,10 +45,31 @@ Ostream& toString(Ostream& os, const UList<char>& list)
 }
 
 
-void printInfo(const OListStream& buf)
+template<class BufType>
+void printInfo(const BufType& buf)
 {
-    Info<< nl << buf.size() << " chars (" << buf.capacity() << " capacity) ";
+    Info<< nl << "=========================" << endl;
-    toString(Info, buf.list()) << endl;
+    buf.print(Info);
+    toString(Info, buf.list());
+    Info<< nl << "=========================" << endl;
+}
+
+
+void printTokens(Istream& is)
+{
+    label count = 0;
+    token t;
+    while (is.good())
+    {
+        is >> t;
+        if (t.good())
+        {
+            ++count;
+            Info<<"token: " << t << endl;
+        }
+    }
+
+    Info<< count << " tokens" << endl;
 }
 
 
@@ -58,18 +79,126 @@ void printInfo(const OListStream& buf)
 int main(int argc, char *argv[])
 {
     // Buffer storage
-    DynamicList<char> storage(8);
+    DynamicList<char> storage(16);
 
     OListStream obuf(std::move(storage));
-    obuf << 1002 << " " << "abcd" << " " << "def" << " " << 3.14159 << ";\n";
+
+    obuf.setBlockSize(100);
+
+    printInfo(obuf);
+
+    // Fill with some content
+    for (label i = 0; i < 50; ++i)
+    {
+        obuf<< 1002 << " " << "abcd" << " "
+            << "def" << " " << 3.14159 << ";\n";
+    }
 
     printInfo(obuf);
 
     obuf.rewind();
-    obuf << 100;
+    printInfo(obuf);
+
+    for (label i=0; i < 10; ++i)
+    {
+        obuf << "item" << i << "\n";
+    }
 
     printInfo(obuf);
 
+    obuf.shrink();
+
+    Info<< "after shrink" << nl;
+    printInfo(obuf);
+
+    // Add some more
+    for (label i=10; i < 15; ++i)
+    {
+        obuf << "more" << i << nl;
+    }
+
+    Info<< "appended more" << nl;
+    printInfo(obuf);
+
+    // Overwrite at some position
+    obuf.stdStream().rdbuf()->pubseekpos(0.60 * obuf.size());
+    obuf << "<" << nl << "OVERWRITE" << nl;
+
+    Info<<"after overwrite" << nl;
+    printInfo(obuf);
+
+    Info<< "transfer contents to a List or IListStream" << nl;
+
+    IListStream ibuf(obuf.xfer());
+
+    Info<<"original:";
+    printInfo(obuf);
+
+    Info<<"new input:" << nl;
+    printInfo(ibuf);
+
+    printTokens(ibuf);
+
+    // Create from other storage types
+
+    Info<< nl;
+    {
+        Info<<"create std::move(List)" << endl;
+        List<char> list(16, 'A');
+
+        Info<<"input:";
+        toString(Info, list) << endl;
+
+        OListStream buf1(std::move(list));
+        for (label i = 0; i < 26; ++i)
+        {
+            buf1 << char('A' +i);
+        }
+        for (label i = 0; i < 26; ++i)
+        {
+            buf1 << char('a' +i);
+        }
+
+        Info<<"orig:";
+        toString(Info, list) << endl;
+
+        printInfo(buf1);
+    }
+
+    Info<< nl;
+
+    List<char> written;
+    {
+        Info<<"create List.xfer()" << endl;
+        List<char> list(16, 'B');
+
+        Info<<"input:";
+        toString(Info, list) << endl;
+
+        OListStream buf1(list.xfer());
+        for (label i = 0; i < 26; ++i)
+        {
+            buf1 << char('A' + i);
+        }
+        for (label i = 0; i < 26; ++i)
+        {
+            buf1 << char('a' +i);
+        }
+
+        Info<<"orig:";
+        toString(Info, list) << endl;
+
+        printInfo(buf1);
+
+        // Move back to written
+        written = buf1.xfer();
+
+        printInfo(buf1);
+    }
+    Info<<"'captured' content ";
+    toString(Info, written);
+
+
     Info<< "\nEnd\n" << endl;
 
     return 0;

applications/test/UIBufStream/Make/files

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

applications/test/UIBufStream/Make/options

@@ -1,2 +0,0 @@
-/* EXE_INC = -I$(LIB_SRC)/finiteVolume/lnInclude */
-/* EXE_LIBS = -lfiniteVolume */

applications/test/UIListStream/Make/files

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

applications/test/UIListStream/Make/options

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

applications/test/UIListStream/Test-UIListStream.C

@@ -25,14 +25,54 @@ Description
 
 \*---------------------------------------------------------------------------*/
 
-#include "UIBufStream.H"
+#include "UListStream.H"
-#include "UOBufStream.H"
 #include "wordList.H"
 #include "IOstreams.H"
 #include "argList.H"
 
 using namespace Foam;
 
+Ostream& toString(Ostream& os, const UList<char>& list)
+{
+    os << '"';
+    for (const char c : list)
+    {
+        os << c;
+    }
+    os << '"';
+
+    return os;
+}
+
+
+template<class BufType>
+void printInfo(const BufType& buf)
+{
+    Info<< nl << "=========================" << endl;
+    buf.print(Info);
+    toString(Info, buf.list());
+    Info<< nl << "=========================" << endl;
+}
+
+
+void printTokens(Istream& is)
+{
+    label count = 0;
+    token t;
+    while (is.good())
+    {
+        is >> t;
+        if (t.good())
+        {
+            ++count;
+            Info<<"token: " << t << endl;
+        }
+    }
+
+    Info<< count << " tokens" << endl;
+}
+
+
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 // Main program:
 
@@ -41,10 +81,10 @@ int main(int argc, char *argv[])
     // Buffer storage
     DynamicList<char> storage(1000);
 
-    UOBufStream obuf(storage);
+    UOListStream obuf(storage);
     obuf << 1002 << " " << "abcd" << " " << "def" << " " << 3.14159 << ";\n";
 
-    Info<<"formatted: " << obuf.size() << " chars" << endl;
+    obuf.print(Info);
 
     // Match size
     storage.resize(obuf.size());
@@ -53,31 +93,14 @@ int main(int argc, char *argv[])
 
     // Attach input buffer - could also do without previous resize
 
-    UIBufStream ibuf(storage, storage.size());
+    UIListStream ibuf(storage);
 
-    token t;
+    printTokens(ibuf);
-
-    while (ibuf.good())
-    {
-        ibuf >> t;
-        if (t.good())
-        {
-            Info<<"token: " << t << endl;
-        }
-    }
 
     Info<< nl << "Repeat..." << endl;
     ibuf.rewind();
 
-    while (ibuf.good())
+    printTokens(ibuf);
-    {
-        ibuf >> t;
-        if (t.good())
-        {
-            Info<<"token: " << t << endl;
-        }
-    }
-
 
     Info<< "\nEnd\n" << endl;
 

src/OpenFOAM/Make/files

@@ -175,6 +175,9 @@ $(hashes)/base64Layer.C
 gzstream = $(Streams)/gzstream
 $(gzstream)/gzstream.C
 
+memstream = $(Streams)/memory
+$(memstream)/ListStream.C
+
 Fstreams = $(Streams)/Fstreams
 $(Fstreams)/IFstream.C
 $(Fstreams)/OFstream.C

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

@@ -79,11 +79,6 @@ protected:
         {}
 
 
-    //- Destructor
-    ~StringStreamAllocator()
-    {}
-
-
 public:
 
     // Public Member Functions
@@ -112,6 +107,8 @@ class IStringStream
     public StringStreamAllocator<std::istringstream>,
     public ISstream
 {
+    typedef StringStreamAllocator<std::istringstream> allocator_type;
+
 public:
 
     // Constructors
@@ -125,7 +122,7 @@ public:
             const Foam::string& name="input"
         )
         :
-            StringStreamAllocator<std::istringstream>(buffer),
+            allocator_type(buffer),
             ISstream(stream_, name, format, version)
         {}
 
@@ -139,7 +136,7 @@ public:
             const Foam::string& name="input"
         )
         :
-            StringStreamAllocator<std::istringstream>(buffer),
+            allocator_type(buffer),
             ISstream(stream_, name, format, version)
         {}
 
@@ -147,28 +144,23 @@ public:
         //- Construct as copy of content
         IStringStream(const IStringStream& str)
         :
-            StringStreamAllocator<std::istringstream>(str.str()),
+            allocator_type(str.str()),
             ISstream(stream_, str.name(), str.format(), str.version())
         {}
 
 
-    //- Destructor
-    ~IStringStream()
-    {}
-
-
     // Member Functions
 
-        //- Print description to Ostream
-        void print(Ostream& os) const;
-
         //- Reset the input buffer and rewind the stream
-        void reset(const std::string& s)
+        virtual void reset(const std::string& s)
         {
             this->str(s);
             this->rewind();
         }
 
+        //- Print description to Ostream
+        virtual void print(Ostream& os) const;
+
 
     // Member operators
 
@@ -192,6 +184,8 @@ class OStringStream
     public StringStreamAllocator<std::ostringstream>,
     public OSstream
 {
+    typedef StringStreamAllocator<std::ostringstream> allocator_type;
+
 public:
 
     // Constructors
@@ -203,7 +197,7 @@ public:
             versionNumber version=currentVersion
         )
         :
-            StringStreamAllocator<std::ostringstream>(),
+            allocator_type(),
             OSstream(stream_, "output", format, version)
         {}
 
@@ -211,16 +205,11 @@ public:
         //- Construct as copy of content
         OStringStream(const OStringStream& str)
         :
-            StringStreamAllocator<std::ostringstream>(str.str()),
+            allocator_type(str.str()),
             OSstream(stream_, str.name(), str.format(), str.version())
         {}
 
 
-    //- Destructor
-    ~OStringStream()
-    {}
-
-
     // Member Functions
 
         //- Reset the output buffer and rewind the stream
@@ -231,14 +220,14 @@ public:
         }
 
         //- Rewind the output stream
-        void rewind()
+        virtual void rewind()
         {
             // pubseekpos() instead of seekp() for symmetry with other classes
             stream_.rdbuf()->pubseekpos(0, std::ios_base::out);
         }
 
         //- Print description to Ostream
-        void print(Ostream& os) const;
+        virtual void print(Ostream& os) const;
 
 };
 

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

@@ -112,8 +112,6 @@ public:
 
     // Member Functions
 
-      // Access
-
         //- This hides both signatures of std::basic_ios::rdbuf()
         sha1buf* rdbuf()
         {
@@ -155,11 +153,6 @@ protected:
         {}
 
 
-    //- Destructor
-    ~OSHA1streamAllocator()
-    {}
-
-
 public:
 
     // Member Functions
@@ -223,11 +216,6 @@ public:
         {}
 
 
-    //- Destructor
-    ~OSHA1stream()
-    {}
-
-
     // Member functions
 
         //- Clear the SHA1 calculation

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

@@ -1,266 +0,0 @@
-/*---------------------------------------------------------------------------*\
-  =========                 |
-  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
-   \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2016-2017 OpenCFD Ltd.
-     \\/     M anipulation  |
--------------------------------------------------------------------------------
-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::BufStreamAllocator
-
-Description
-    Helper for memory buffer streams such as UIBufStream, UOBufStream
-
-\*---------------------------------------------------------------------------*/
-
-#ifndef BufStreamAllocator_H
-#define BufStreamAllocator_H
-
-#include <type_traits>
-#include <sstream>
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-namespace Foam
-{
-
-/*---------------------------------------------------------------------------*\
-                          Class memorybuf Declaration
-\*---------------------------------------------------------------------------*/
-
-//- A streambuf class for using externally allocated memory for its buffer
-class memorybuf
-:
-    public std::streambuf
-{
-protected:
-
-    // Protected members
-
-        //- 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
-        )
-        {
-            const bool testin  = which & std::ios_base::in;
-            const bool testout = which & std::ios_base::out;
-
-            if (way == std::ios_base::beg)
-            {
-                if (testin)
-                {
-                    setg(eback(), eback(), egptr());
-                    gbump(off);
-                }
-                if (testout)
-                {
-                    setp(pbase(), epptr());
-                    pbump(off);
-                }
-
-                return off;
-            }
-
-            if (way == std::ios_base::cur)
-            {
-                if (testin)
-                {
-                    gbump(off);
-                }
-                if (testout)
-                {
-                    pbump(off);
-                }
-            }
-            else if (way == std::ios_base::end)
-            {
-                if (testin)
-                {
-                    gbump(off);
-                }
-                if (testout)
-                {
-                    pbump(off);
-                }
-            }
-
-            if (testin)
-            {
-                return gptr() - eback();
-            }
-            if (testout)
-            {
-                return pptr() - pbase();
-            }
-
-            return -1;
-        }
-
-
-        //- Set position pointer to absolute position
-        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);
-        }
-
-
-        //- Get sequence of characters
-        virtual std::streamsize xsgetn(char* s, std::streamsize n)
-        {
-            std::streamsize count = 0;
-
-            // some optimization could be possible here
-            while (count < n && gptr() < egptr())
-            {
-                *(s + count++) = *(gptr());
-                gbump(1);
-            }
-
-            return count;
-        }
-
-
-        //- Put sequence of characters
-        virtual std::streamsize xsputn(const char* s, std::streamsize n)
-        {
-            std::streamsize count = 0;
-
-            // some optimization could be possible here
-            while (count < n && pptr() < epptr())
-            {
-                *(pptr()) = *(s + count++);
-                pbump(1);
-            }
-
-            return count;
-        }
-
-
-public:
-
-    // Constructors
-
-        //- Construct for specified buffer
-        memorybuf(char* buffer, std::streamsize num)
-        {
-            setg(buffer, buffer, buffer + num);
-            setp(buffer, buffer + num);
-        }
-
-};
-
-
-/*---------------------------------------------------------------------------*\
-                     Class BufStreamAllocator Declaration
-\*---------------------------------------------------------------------------*/
-
-//- An stream/stream-buffer allocator for external buffers
-template<class StreamType, bool Manage=false>
-class BufStreamAllocator
-{
-    // Private data
-
-        //- Storage
-        char *storage_;
-
-        //- The number of bytes in the storage
-        std::streamsize len_;
-
-        //- Reference to the underlying buffer
-        memorybuf buf_;
-
-protected:
-
-    // Protected data
-
-        typedef StreamType stream_type;
-
-        //- The stream pointer
-        stream_type stream_;
-
-
-    // Constructors
-
-        //- Construct with buffer and number of bytes
-        BufStreamAllocator(char *buffer, size_t nbytes)
-        :
-            storage_(buffer),
-            len_(nbytes),
-            buf_(storage_, len_),
-            stream_(&buf_)
-        {}
-
-
-    //- Destructor
-    ~BufStreamAllocator()
-    {
-        // Possible cleanup of storage
-        if (Manage && storage_)
-        {
-            delete storage_;
-            storage_ = nullptr;
-        }
-    }
-
-
-    // Protected Member Functions
-
-
-        //- Position of the get buffer
-        std::streampos tellg() const
-        {
-            return const_cast<stream_type&>(stream_).tellg();
-        }
-
-        //- Position of the put buffer
-        std::streampos tellp() const
-        {
-            return const_cast<stream_type&>(stream_).tellp();
-        }
-
-
-public:
-
-    // Public Member Functions
-
-        //- Move to buffer start, clear errors
-        void rewind()
-        {
-            stream_.rdbuf()->pubseekpos(0);
-            stream_.clear(); // for safety, clear any old errors
-        }
-};
-
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-} // End namespace Foam
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
-#endif
-
-// ************************************************************************* //

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

@@ -0,0 +1,245 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2017 OpenCFD Ltd.
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+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 IListStream_H
+#define IListStream_H
+
+#include "List.H"
+#include "UIListStream.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+
+/*---------------------------------------------------------------------------*\
+                    Class IListStreamAllocator Declaration
+\*---------------------------------------------------------------------------*/
+
+//- An stream/stream-buffer input allocator for with List storage
+class IListStreamAllocator
+:
+    private List<char>,
+    public UIListStreamAllocator
+{
+protected:
+
+    // Constructors
+
+        //- Construct with an empty list
+        IListStreamAllocator()
+        :
+            List<char>(),
+            UIListStreamAllocator(list_storage())
+        {}
+
+        //- Move construct from an existing List
+        IListStreamAllocator(List<char>&& buffer)
+        :
+            List<char>(std::move(buffer)),
+            UIListStreamAllocator(list_storage())
+        {}
+
+
+        //- Move construct from an existing DynamicList
+        template<int SizeMin>
+        IListStreamAllocator(DynamicList<char,SizeMin>&& buffer)
+        :
+            List<char>(std::move(buffer)),
+            UIListStreamAllocator(list_storage())
+        {}
+
+        //- Transfer (move) construct
+        IListStreamAllocator(const Xfer<List<char>>& buffer)
+        :
+            List<char>(buffer),
+            UIListStreamAllocator(list_storage())
+        {}
+
+
+    // Protected Member Functions
+
+        //- Convenience method to address the underlying List storage
+        inline List<char>& list_storage()
+        {
+            return static_cast<List<char>&>(*this);
+        }
+
+public:
+
+    // Member Functions
+
+        //- The current get position in the buffer
+        using UIListStreamAllocator::size;
+
+        //- Clear storage
+        inline void clearStorage()
+        {
+            list_storage().clear();
+            sync_gbuffer_to_list();
+        }
+
+        //- Transfer contents to the Xfer container as a plain List
+        inline Xfer<List<char>> xfer()
+        {
+            Xfer<List<char>> moved = list_storage().xfer();
+
+            // Update buffer pointers for remaining (zero) size list
+            sync_gbuffer_to_list(); // or rewind
+
+            return moved;
+        }
+};
+
+
+/*---------------------------------------------------------------------------*\
+                         Class IListStream Declaration
+\*----------------------------------------------d-----------------------------*/
+
+//- An ISstream with internal List storage
+class IListStream
+:
+    public IListStreamAllocator,
+    public ISstream
+{
+    typedef IListStreamAllocator allocator_type;
+
+public:
+
+    // Constructors
+
+        //- Construct with an empty list
+        IListStream
+        (
+            streamFormat format=ASCII,
+            versionNumber version=currentVersion,
+            const Foam::string& name="input"
+        )
+        :
+            allocator_type(),
+            ISstream(stream_, name, format, version)
+        {}
+
+
+        //- Move construct from an existing List
+        IListStream
+        (
+            List<char>&& buffer,
+            streamFormat format=ASCII,
+            versionNumber version=currentVersion,
+            const Foam::string& name="input"
+        )
+        :
+            allocator_type(std::move(buffer)),
+            ISstream(stream_, name, format, version)
+        {}
+
+
+        //- Move construct from an existing DynamicList
+        template<int SizeMin>
+        IListStream
+        (
+            DynamicList<char,SizeMin>&& buffer,
+            streamFormat format=ASCII,
+            versionNumber version=currentVersion,
+            const Foam::string& name="input"
+        )
+        :
+            allocator_type(std::move(buffer)),
+            ISstream(stream_, name, format, version)
+        {}
+
+
+        //- Transfer (move) construct
+        IListStream
+        (
+            const Xfer<List<char>>& buffer,
+            streamFormat format=ASCII,
+            versionNumber version=currentVersion,
+            const Foam::string& name="input"
+        )
+        :
+            allocator_type(buffer),
+            ISstream(stream_, name, format, 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 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
+        {
+            return const_cast<Istream&>(static_cast<const Istream&>(*this));
+        }
+};
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //

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

@@ -0,0 +1,72 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2017 OpenCFD Ltd.
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+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/>.
+
+\*---------------------------------------------------------------------------*/
+
+#include "UListStream.H"
+#include "ListStream.H"
+#include "OCountStream.H"
+
+// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
+
+void Foam::IListStream::print(Ostream& os) const
+{
+    os  << "IListStream: ";
+    printBufInfo(os);
+    os  << Foam::endl;
+}
+
+
+void Foam::UIListStream::print(Ostream& os) const
+{
+    os  << "UIListStream: ";
+    printBufInfo(os);
+    os  << Foam::endl;
+}
+
+
+void Foam::OListStream::print(Ostream& os) const
+{
+    os  << "OListStream: ";
+    printBufInfo(os);
+    os  << Foam::endl;
+}
+
+
+void Foam::UOListStream::print(Ostream& os) const
+{
+    os  << "UOListStream: ";
+    printBufInfo(os);
+    os  << Foam::endl;
+}
+
+
+void Foam::OCountStream::print(Ostream& os) const
+{
+    os  << "OCountStream: ";
+    printBufInfo(os);
+    os  << Foam::endl;
+}
+
+
+// ************************************************************************* //

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

@@ -0,0 +1,37 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2017 OpenCFD Ltd.
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+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 managed List storage.
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef ListStream_H
+#define ListStream_H
+
+#include "IListStream.H"
+#include "OListStream.H"
+
+#endif
+
+// ************************************************************************* //

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

@@ -52,29 +52,30 @@ class countstreambuf
     // Private data
 
         //- The number of bytes
-        std::streamsize n_;
+        std::streamsize size_;
 
 protected:
-    // Protected members
 
-        //- Put sequence of characters
+    //- Simply handle output counting via overflow
-        virtual std::streamsize xsputn(const char* s, std::streamsize num)
+    virtual int overflow(int c = EOF)
     {
-            n_ += num;
+        if (c != EOF)
-            return num;
+        {
+            ++size_;
+        }
+        return c;
     }
-
 
     //- Set position pointer to absolute position
     //  For the counter, any positioning is ignored and it always acts like
     //  seekpos(0), which resets the count.
     virtual std::streampos seekpos
     (
-            std::streampos sp,
+        std::streampos,
         std::ios_base::openmode which = std::ios_base::in|std::ios_base::out
     )
     {
-            n_ = 0;
+        size_ = 0;
         return 0;
     }
 
@@ -83,19 +84,19 @@ public:
 
     // Constructors
 
-        //- Construct null
+        //- Construct null, or with precount size
-        countstreambuf()
+        countstreambuf(std::streamsize precount=0)
         :
-            n_(0)
+            size_(precount)
         {}
 
 
     // Access
 
-        //- Get number of bytes counted
+        //- Number of bytes counted
         std::streamsize size() const
         {
-            return n_;
+            return size_;
         }
 };
 
@@ -154,6 +155,62 @@ public:
 };
 
 
+/*---------------------------------------------------------------------------*\
+                    Class OCountStreamAllocator Declaration
+\*---------------------------------------------------------------------------*/
+
+//- An stream/stream-buffer allocator for counting
+class OCountStreamAllocator
+{
+protected:
+
+    // Protected data
+
+        typedef std::ostream stream_type;
+
+        //- The stream buffer
+        countstreambuf buf_;
+
+        //- The output stream
+        stream_type stream_;
+
+
+    // Constructors
+
+        //- Construct null, or with precount size
+        OCountStreamAllocator(std::streamsize precount=0)
+        :
+            buf_(precount),
+            stream_(&buf_)
+        {}
+
+
+    // Protected Member Functions
+
+        void printBufInfo(Ostream& os) const
+        {
+            os << "count=" << buf_.size();
+        }
+
+public:
+
+    // Member Functions
+
+        //- The number of bytes counted
+        std::streamsize size() const
+        {
+            return buf_.size();
+        }
+
+        //- Rewind the stream, reset the count
+        void rewind()
+        {
+            buf_.pubseekpos(0);
+            stream_.clear(); // for safety, clear any old errors
+        }
+};
+
+
 /*---------------------------------------------------------------------------*\
                         Class OCountStream Declaration
 \*---------------------------------------------------------------------------*/
@@ -161,17 +218,10 @@ public:
 //- An output stream for calculating byte counts
 class OCountStream
 :
-    private ocountstream,
+    public OCountStreamAllocator,
     public OSstream
 {
-
+    typedef OCountStreamAllocator allocator_type;
-    // Private Member Functions
-
-        //- Disallow default bitwise copy construct
-        OCountStream(const OCountStream&) = delete;
-
-        //- Disallow default bitwise assignment
-        void operator=(const OCountStream&) = delete;
 
 public:
 
@@ -184,39 +234,30 @@ public:
             versionNumber version=currentVersion
         )
         :
-            ocountstream(),
+            allocator_type(),
-            OSstream
+            OSstream(stream_, "output", format, version)
-            (
-                static_cast<ocountstream&>(*this),
-                "output",
-                format,
-                version
-        )
         {}
 
-
+        //- Copy construct
-    //- Destructor
+        OCountStream(const OCountStream& os)
-    ~OCountStream()
+        :
+            allocator_type(os.size()),
+            OSstream(stream_, os.name(), os.format(), os.version())
         {}
 
 
     // Member functions
 
-      // Access
-
-        //- Return the number of bytes counted
-        using ocountstream::size;
-
-
-      // Edit
-
         //- Rewind the stream, reset the count, clearing any old errors
-        void rewind()
+        virtual void rewind()
         {
-            ocountstream::rewind();
+            allocator_type::rewind();
             setGood();  // resynchronize with internal state
         }
 
+        //- Print description to Ostream
+        virtual void print(Ostream& os) const;
+
 };
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

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

@@ -25,16 +25,27 @@ Class
     Foam::OListStream
 
 Description
-    An output stream that writes to a DynamicList.
+    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 with a 256 byte block increment.
+    These values can be changed on construction of via the
+    reserve() and setBlockSize() methods.
+
+See Also
+    Foam::IListStream
+    Foam::UOListStream
+    Foam::UIListStream
 
 \*---------------------------------------------------------------------------*/
 
 #ifndef OListStream_H
 #define OListStream_H
 
-#include <sstream>
 #include "DynamicList.H"
 #include "OSstream.H"
+#include "memoryStreamBuffer.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
@@ -48,114 +59,100 @@ class OListStreamAllocator;
                     Class OListStreamAllocator Declaration
 \*---------------------------------------------------------------------------*/
 
-//- An stream/stream-buffer allocator for external buffers
+//- An stream/stream-buffer output allocator for lists
 class OListStreamAllocator
 {
-    //- A streambuf adapter to output to a DynamicList
+    //- A streambuf adapter to output to a List
-    class olistbuf
+    class listbuf
     :
-        public std::streambuf
+        public memorybuf::output
     {
         friend OListStreamAllocator;
 
-        //- Underlying list storage
+        //- Helper for setting the block size.
-        DynamicList<char,512> storage_;
+        //  Small list minimum of 64 bytes.
-
+        static int min_size(int n)
-
-        //- Adjust buffer pointers to agree with list sizes
-        inline void syncBufferPointers()
         {
-            setp(storage_.data(), storage_.data() + storage_.capacity());
+            return max(64, n);
-            pbump(storage_.size());
         }
 
-        //- Adjust addressed list size to agree with buffer pointers
+        //- Block size when resizing the list
-        inline void syncListSize()
+        int block_ = 256;
-        {
+
-            storage_.setSize(pptr() - pbase());
+        //- Underlying list storage.
-        }
+        //  Internally manage like a DynamicList, but the addressable size
+        //  is known through the stream pointers.
+        List<char> storage_;
 
 
     protected:
 
-        // Protected members
+        //- Increment capacity directly and
-
+        //  adjust buffer pointers to agree with list dimensions
-            //- Set position pointer to relative position
+        inline void minCapacity
-            virtual std::streampos seekoff
         (
-                std::streamoff off,
+            const std::streamsize n,
-                std::ios_base::seekdir way,
+            const std::streamsize cur = 0
-                std::ios_base::openmode which = std::ios_base::out
         )
         {
-                const bool testout = which & std::ios_base::out;
+            const auto newEnd = n + cur;
-
+            if (newEnd > storage_.size())
-                if (way == std::ios_base::beg)
             {
-                    if (testout)
+                auto newCapacity =
-                    {
-                        setp(pbase(), epptr());
-                        pbump(off);
-                    }
-
-                    return off;
-                }
-
-                if (way == std::ios_base::cur)
-                {
-                    if (testout)
-                    {
-                        pbump(off);
-                    }
-                }
-                else if (way == std::ios_base::end)
-                {
-                    if (testout)
-                    {
-                        pbump(off);
-                    }
-                }
-
-                if (testout)
-                {
-                    return pptr() - pbase();
-                }
-
-                return -1;
-            }
-
-
-            //- Set position pointer to absolute position
-            virtual std::streampos seekpos
                 (
-                std::streampos pos,
+                    (storage_.size() + block_)
-                std::ios_base::openmode which = std::ios_base::out
+                  - (storage_.size() % block_)
-            )
+                );
-            {
-                if (which & std::ios_base::out)
-                {
-                    setp(pbase(), epptr());
-                    pbump(pos);
 
-                    return pptr() - pbase();
+                while (newCapacity < newEnd)
+                {
+                    newCapacity += block_;
                 }
 
-                return -1;
+                // Info<<"request:" << newEnd
+                //     << " cur cap:" << storage_.size()
+                //     << " new cap:" << newCapacity
+                //     << " pos:" << cur
+                //     << " incr:" << incr << endl;
+
+                storage_.setSize(newCapacity);
+                sync_pbuffer_to_list();
+                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)
         {
-                const std::streamsize newlen = n + storage_.size();
+            // Enough space so that appends work without problem
-
+            minCapacity(n, tellp());
-                if (newlen > storage_.capacity())
-                {
-                    // Either use reserve(), or setCapacity() directly
-                    // with finer control over growth
-                    storage_.reserve(newlen);
-                    syncBufferPointers();
-                }
 
             std::streamsize count = 0;
             while (count < n && pptr() < epptr())
@@ -164,90 +161,108 @@ class OListStreamAllocator
                 pbump(1);
             }
 
-                // Synchronize list size with output
-                syncListSize();
-
             return count;
         }
 
+        //- Initialize put buffer
+        void init_pbuffer(const std::streamsize n)
+        {
+            set_pbuffer(storage_);
+            minCapacity(n);
+        }
+
 
     public:
 
       // Constructors
 
-            //- Construct with an empty list
+        //- Construct with an empty list, or specified number of reserved bytes
-            olistbuf()
+        listbuf(size_t nbytes = 512)
-            :
-                storage_(1024)
-            {
-                syncBufferPointers();
-            }
-
-
-            //- Construct with a specified number of reserved bytes
-            olistbuf(size_t nbytes)
         :
             storage_()
         {
-                storage_.reserve(std::max(label(nbytes),1024));
+            init_pbuffer(min_size(nbytes));
-                syncBufferPointers();
         }
 
-
+        //- Move construct content from an existing List
-            //- Move construct from an existing List
+        listbuf(List<char>&& buffer)
-            olistbuf(List<char>&& buffer)
         :
             storage_(std::move(buffer))
         {
-                syncBufferPointers();
+            init_pbuffer(block_);
         }
 
-
+        //- Move construct content from an existing DynamicList
-            //- Move construct from an existing DynamicList
         template<int AnySize>
-            olistbuf(DynamicList<char,AnySize>&& buffer)
+        listbuf(DynamicList<char,AnySize>&& buffer)
         :
             storage_(std::move(buffer))
         {
-                syncBufferPointers();
+            init_pbuffer(block_);
+        }
+
+        //- Transfer (move) construct
+        listbuf(const Xfer<List<char>>& buffer)
+        :
+            storage_(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
+        inline void sync_pbuffer_to_list()
+        {
+            set_pbuffer(storage_);
+        }
+
+        //- Clear storage
+        inline void clearStorage()
+        {
+            storage_.clear();
+            sync_pbuffer_to_list();
+        }
+
+        //- Shrink to addressed storage
+        inline void shrink()
+        {
+            const auto cur = tellp();
+            storage_.setSize(cur);
+            sync_pbuffer_to_list();
+            pbump(cur);
         }
     };
 
-
-    // Private data
-
-        //- Reference to the underlying buffer
-        olistbuf buf_;
-
-
 protected:
 
     // Protected data
 
         typedef std::ostream stream_type;
 
-        //- The output stream
+        //- The stream buffer
+        listbuf buf_;
+
+        //- The stream
         stream_type stream_;
 
 
     // Constructors
 
-        //- Construct with an empty list
+        //- Construct with an empty list or specified number of reserved bytes
-        OListStreamAllocator()
+        OListStreamAllocator(size_t nbytes = 512)
-        :
-            buf_(),
-            stream_(&buf_)
-        {}
-
-
-        //- Construct with a specified number of reserved bytes
-        OListStreamAllocator(size_t nbytes)
         :
             buf_(nbytes),
             stream_(&buf_)
         {}
 
-
         //- Move construct from an existing List
         OListStreamAllocator(List<char>&& buffer)
         :
@@ -255,7 +270,6 @@ protected:
             stream_(&buf_)
         {}
 
-
         //- Move construct from an existing DynamicList
         template<int SizeMin>
         OListStreamAllocator(DynamicList<char,SizeMin>&& buffer)
@@ -264,71 +278,117 @@ protected:
             stream_(&buf_)
         {}
 
-
+        //- Transfer (move) construct
-    //- Destructor
+        OListStreamAllocator(const Xfer<List<char>>& buffer)
-    ~OListStreamAllocator()
+        :
+            buf_(buffer),
+            stream_(&buf_)
         {}
 
 
+    // Protected Member Functions
+
+        void printBufInfo(Ostream& os) const
+        {
+            os  << "pos=" << buf_.tellp()
+                << " capacity=" << buf_.capacity()
+                << " block=" << buf_.block_;
+        }
+
 public:
 
     // Member Functions
 
-        //- Content as a list of characters
+        //- The current list output capacity
-        UList<char> list() const
+        inline label capacity() const
+        {
+            return buf_.capacity();
+        }
+
+
+        //- 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);
+        }
+
+
+        //- The current output position in the buffer,
+        //  which is also the addressed list size
+        inline label size() const
+        {
+            return buf_.tellp();
+        }
+
+
+        //- Const access to written contents as a list of characters
+        inline const UList<char> list() const
         {
             return UList<char>
             (
                 const_cast<char*>(buf_.storage_.cdata()),
-                buf_.storage_.size()
+                buf_.tellp()
             );
         }
 
 
-        //- Content as a list of characters
+        //- Non-const access to written contents as a list of characters
-        UList<char>& list()
+        inline UList<char> list()
         {
-            return static_cast<UList<char>&>(buf_.storage_);
+            return UList<char>(buf_.storage_.data(), buf_.tellp());
-        }
-
-        //- Return the current list capacity
-        inline label capacity() const
-        {
-            return buf_.storage_.capacity();
         }
 
 
-        //- Reserve allocation space for at least this size.
+        //- Transfer contents to the Xfer container as a plain List
-        inline void reserve(const label nElem)
+        inline Xfer<List<char>> xfer()
         {
-            buf_.storage_.reserve(nElem);
+            buf_.shrink();  // Shrink to addressed area
-            buf_.syncBufferPointers();
+            auto lst = buf_.storage_.xfer();
-        }
+            buf_.sync_pbuffer_to_list();
-
+            return lst;
-
-        //- Return the current output position in the buffer
-        //  The same as the DynamicList::size()
-        std::streampos size() const
-        {
-            return const_cast<stream_type&>(stream_).tellp();
         }
 
 
         //- Move to buffer start, clear errors
         void rewind()
         {
-            buf_.storage_.clear();
+            buf_.pubseekpos(0, std::ios_base::out);
-            buf_.syncBufferPointers();
             stream_.clear(); // for safety, clear any old errors
         }
+
+        //- 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
+        }
+
 };
 
 
 /*---------------------------------------------------------------------------*\
                          Class OListStream Declaration
-\*----------------------------------------------d-----------------------------*/
+\*---------------------------------------------------------------------------*/
 
-//- An OSstream attached a DynamicList
+//- An OSstream attached to a List
 class OListStream
 :
     public OListStreamAllocator,
@@ -348,7 +408,7 @@ public:
         )
         :
             allocator_type(),
-            OSstream(stream_, "output", format,version)
+            OSstream(stream_, "output", format, version)
         {}
 
 
@@ -391,16 +451,30 @@ public:
             OSstream(stream_, "output", format, version)
         {}
 
-
+        //- Transfer (move) construct
-    //- Destructor
+        OListStream
-    ~OListStream()
+        (
+            const Xfer<List<char>>& buffer,
+            streamFormat format=ASCII,
+            versionNumber version=currentVersion
+        )
+        :
+            allocator_type(buffer),
+            OSstream(stream_, "output", format, version)
         {}
 
 
     // Member functions
 
         //- Rewind the stream, clearing any old errors
-        using allocator_type::rewind;
+        virtual void rewind()
+        {
+            allocator_type::rewind();
+            setGood();  // resynchronize with internal state
+        }
+
+        //- Print description to Ostream
+        virtual void print(Ostream& os) const;
 
 };
 

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

@@ -22,7 +22,7 @@ License
     along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
 
 Class
-    Foam::UIBufStream
+    Foam::UIListStream
 
 Description
     Similar to IStringStream but using an externally managed buffer for its
@@ -41,7 +41,7 @@ Description
         buffer.setSize(nread);            // content size
 
         // construct dictionary, or something else
-        UIBufStream is(buffer)
+        UIListStream is(buffer)
         dictionary dict1(is);
 
         // sometime later
@@ -49,16 +49,23 @@ Description
         buffer.setSize(nread);              // content size
 
         // without intermediate variable
-        dictionary dict2(UIBufStream(buffer)());
+        dictionary dict2(UIListStream(buffer)());
     \endcode
 
+See Also
+    Foam::IListStream
+    Foam::OListStream
+    Foam::UOListStream
+
 \*---------------------------------------------------------------------------*/
 
-#ifndef UIBufStream_H
+#ifndef UIListStream_H
-#define UIBufStream_H
+#define UIListStream_H
 
-#include "BufStreamAllocator.H"
+#include "FixedList.H"
+#include "UList.H"
 #include "ISstream.H"
+#include "memoryStreamBuffer.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
@@ -66,22 +73,149 @@ namespace Foam
 {
 
 /*---------------------------------------------------------------------------*\
-                         Class UIBufStream Declaration
+                       Class UIListAllocator Declaration
 \*---------------------------------------------------------------------------*/
 
-class UIBufStream
+//- An stream/stream-buffer input allocator for a externally allocated lists
+class UIListStreamAllocator
+{
+    //- A streambuf class for input from UList or equivalent
+    class ulistbuf
+    :
+        public memorybuf::input
+    {
+        friend UIListStreamAllocator;
+
+        //- Underlying list storage
+        UList<char> list_;
+
+    public:
+
+        //- Construct for specified buffer
+        ulistbuf(UList<char>& buffer)
+        :
+            list_(buffer)
+        {
+            set_gbuffer(list_);
+        }
+
+        //- Construct for specified buffer
+        ulistbuf(char* buffer, std::streamsize num)
+        :
+            list_(buffer, num)
+        {
+            set_gbuffer(list_);
+        }
+
+        //- Sync get buffer pointers to agree with list dimensions
+        inline void sync_gbuffer_to_list()
+        {
+            set_gbuffer(list_);
+        }
+    };
+
+protected:
+
+    // Protected data
+
+        typedef std::istream stream_type;
+
+        //- The stream buffer
+        ulistbuf buf_;
+
+        //- The stream
+        stream_type stream_;
+
+
+    // Constructors
+
+        //- Construct with list buffer
+        UIListStreamAllocator(UList<char>& list)
+        :
+            buf_(list),
+            stream_(&buf_)
+        {}
+
+        //- Construct with buffer and number of bytes
+        UIListStreamAllocator(char *buffer, size_t nbytes)
+        :
+            buf_(buffer, nbytes),
+            stream_(&buf_)
+        {}
+
+
+    // Protected Member Functions
+
+        //- Sync get buffer pointers to agree with list dimensions
+        inline void sync_gbuffer_to_list()
+        {
+            buf_.sync_gbuffer_to_list();
+        }
+
+        void printBufInfo(Ostream& os) const
+        {
+            os  << "pos=" << buf_.tellg()
+                << " size=" << buf_.list_.size();
+        }
+
+public:
+
+    // Public Member Functions
+
+        //- Const access to available contents as a list of characters
+        inline const UList<char>& list() const
+        {
+            return buf_.list_;
+        }
+
+
+        //- Non-const access to available contents as a list of characters
+        inline UList<char> list()
+        {
+            return buf_.list_;
+        }
+
+
+        //- The list size
+        inline label size() const
+        {
+            return buf_.list_.size();
+        }
+
+
+        //- 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
+        }
+};
+
+
+/*---------------------------------------------------------------------------*\
+                         Class UIListStream Declaration
+\*---------------------------------------------------------------------------*/
+
+class UIListStream
 :
-    public BufStreamAllocator<std::istream,false>,
+    public UIListStreamAllocator,
     public ISstream
 {
-    typedef BufStreamAllocator<std::istream,false> allocator_type;
+    typedef UIListStreamAllocator allocator_type;
 
 public:
 
     // Constructors
 
         //- Construct using specified buffer and number of bytes
-        UIBufStream
+        UIListStream
         (
             const char* buffer,
             size_t nbytes,
@@ -95,8 +229,21 @@ public:
         {}
 
 
+        //- Construct using data area from a FixedList
+        template<unsigned FixedSize>
+        UIListStream
+        (
+            const FixedList<char,FixedSize>& buffer,
+            streamFormat format=ASCII,
+            versionNumber version=currentVersion,
+            const Foam::string& name="input"
+        )
+        :
+            UIListStream(buffer.cdata(), FixedSize, format, version, name)
+        {}
+
         //- Construct using data area from a List and number of bytes
-        UIBufStream
+        UIListStream
         (
             const UList<char>& buffer,
             label size,
@@ -105,13 +252,13 @@ public:
             const Foam::string& name="input"
         )
         :
-            UIBufStream(buffer.cdata(), size, format,version,name)
+            UIListStream(buffer.cdata(), size, format, version, name)
         {}
 
 
         //- Construct using data area from a List and its inherent storage size
         //  Uses addressed size, thus no special treatment for a DynamicList
-        UIBufStream
+        UIListStream
         (
             const UList<char>& buffer,
             streamFormat format=ASCII,
@@ -119,12 +266,7 @@ public:
             const Foam::string& name="input"
         )
         :
-            UIBufStream(buffer.cdata(), buffer.size(), format,version,name)
+            UIListStream(buffer.cdata(), buffer.size(), format, version, name)
-        {}
-
-
-    //- Destructor
-    ~UIBufStream()
         {}
 
 
@@ -145,6 +287,10 @@ public:
         }
 
 
+        //- Print description to Ostream
+        virtual void print(Ostream& os) const;
+
+
     // Member operators
 
         //- A non-const reference to const Istream

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

@@ -0,0 +1,37 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2017 OpenCFD Ltd.
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+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

@@ -22,7 +22,7 @@ License
     along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
 
 Class
-    Foam::UOBufStream
+    Foam::UOListStream
 
 Description
     Similar to OStringStream but using an externally managed buffer for
@@ -38,7 +38,7 @@ Description
         DynamicList<char> buffer(4096);     // allocate some large buffer
 
         {
-            UOBufStream os(buffer);
+            UOListStream os(buffer);
             os << "content1" << " and more content";
             buffer.setSize(os.size());      // synchronize sizes
         }
@@ -46,12 +46,12 @@ Description
         something.write(buffer, buffer.size());
     \endcode
 
-    Although the UOBufStream is quite lightweight, there may be cases
+    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
 
-        UOBufStream os(buffer);
+        UOListStream os(buffer);
         os << "content1" << " and more content";
         buffer.setSize(os.size());          // synchronize sizes
 
@@ -70,41 +70,171 @@ Description
         something.write(buffer, os.size());
     \endcode
 
+See Also
+    Foam::IListStream
+    Foam::OListStream
+    Foam::UIListStream
+
 \*---------------------------------------------------------------------------*/
 
-#ifndef UOBufStream_H
+#ifndef UOListStream_H
-#define UOBufStream_H
+#define UOListStream_H
 
-#include "BufStreamAllocator.H"
+#include "DynamicList.H"
+#include "FixedList.H"
 #include "OSstream.H"
+#include "memoryStreamBuffer.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
 namespace Foam
 {
 
-// Forward declaration
+/*---------------------------------------------------------------------------*\
-template<class T, int SizeMin> class DynamicList;
+                    Class UOListAllocator Declaration
+\*---------------------------------------------------------------------------*/
+
+//- An stream/stream-buffer allocator for external buffers
+class UOListAllocator
+{
+    //- A streambuf adapter for output to UList or equivalent
+    class ulistbuf
+    :
+        public memorybuf::output
+    {
+        friend UOListAllocator;
+
+        //- Underlying list storage
+        UList<char> list_;
+
+    public:
+
+      // Constructors
+
+        //- Construct for specified buffer
+        ulistbuf(char* buffer, std::streamsize num)
+        :
+            list_(buffer, num)
+        {
+            set_pbuffer(list_);
+        }
+
+
+      // Member Functions
+
+        //- Return the current list output capacity
+        inline label capacity() const
+        {
+            return list_.size();
+        }
+
+        //- Sync put buffer pointers to agree with list dimensions
+        inline void sync_pbuffer_to_list()
+        {
+            set_pbuffer(list_);
+        }
+    };
+
+
+protected:
+
+    // Protected data
+
+        typedef std::ostream stream_type;
+
+        //- The stream buffer
+        ulistbuf buf_;
+
+        //- The stream
+        stream_type stream_;
+
+
+    // Constructors
+
+        //- Construct with buffer and number of bytes
+        UOListAllocator(char *buffer, size_t nbytes)
+        :
+            buf_(buffer, nbytes),
+            stream_(&buf_)
+        {}
+
+
+    // Protected Member Functions
+
+        void printBufInfo(Ostream& os) const
+        {
+            os  << "pos=" << buf_.tellp()
+                << " capacity=" << buf_.capacity();
+        }
+
+public:
+
+    // Public Member Functions
+
+        //- 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();
+        }
+
+
+        //- Const access to written contents as a list of characters
+        inline const UList<char> list() const
+        {
+            return UList<char>
+            (
+                const_cast<char*>(buf_.list_.cdata()),
+                buf_.tellp()
+            );
+        }
+
+
+        //- Non-const access to written contents as a list of characters
+        inline UList<char> list()
+        {
+            return UList<char>
+            (
+                const_cast<char*>(buf_.list_.cdata()),
+                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
+        }
+};
 
 
 /*---------------------------------------------------------------------------*\
-                         Class UOBufStream Declaration
+                         Class UOListStream Declaration
 \*---------------------------------------------------------------------------*/
 
 //- An OSstream attached to an unallocated external buffer
-class UOBufStream
+class UOListStream
 :
-    public BufStreamAllocator<std::ostream,false>,
+    public UOListAllocator,
     public OSstream
 {
-    typedef BufStreamAllocator<std::ostream,false> allocator_type;
+    typedef UOListAllocator allocator_type;
 
 public:
 
     // Constructors
 
         //- Construct using specified buffer and number of bytes
-        UOBufStream
+        UOListStream
         (
             char* buffer,
             size_t nbytes,
@@ -113,12 +243,12 @@ public:
         )
         :
             allocator_type(buffer, nbytes),
-            OSstream(stream_, "output", format,version)
+            OSstream(stream_, "output", format, version)
         {}
 
 
         //- Construct using data area from a List and number of bytes
-        UOBufStream
+        UOListStream
         (
             UList<char>& buffer,
             size_t size,
@@ -126,56 +256,58 @@ public:
             versionNumber version=currentVersion
         )
         :
-            UOBufStream(buffer.data(), size, format,version)
+            UOListStream(buffer.data(), size, format, version)
         {}
 
+        //- Construct using data area from a FixedList
+        template<unsigned FixedSize>
+        UOListStream
+        (
+            FixedList<char,FixedSize>& buffer,
+            streamFormat format=ASCII,
+            versionNumber version=currentVersion
+        )
+        :
+            UOListStream(buffer.data(), FixedSize, format, version)
+        {}
 
         //- Construct using data area from a List and its inherent storage size
-        UOBufStream
+        UOListStream
         (
             UList<char>& buffer,
             streamFormat format=ASCII,
             versionNumber version=currentVersion
         )
         :
-            UOBufStream(buffer.data(), buffer.size(), format,version)
+            UOListStream(buffer.data(), buffer.size(), format, version)
         {}
 
 
         //- Construct using data area from a DynamicList and its capacity
         template<int SizeMin>
-        UOBufStream
+        UOListStream
         (
             DynamicList<char,SizeMin>& buffer,
             streamFormat format=ASCII,
             versionNumber version=currentVersion
         )
         :
-            UOBufStream(buffer.data(), buffer.capacity(), format,version)
+            UOListStream(buffer.data(), buffer.capacity(), format, version)
-        {}
-
-
-    //- Destructor
-    ~UOBufStream()
         {}
 
 
     // Member functions
 
-        //- Return the current output position in the buffer
-        std::streampos size() const
-        {
-            return allocator_type::tellp();
-        }
-
-
         //- Rewind the stream, clearing any old errors
-        void rewind()
+        virtual void rewind()
         {
             allocator_type::rewind();
             setGood();  // resynchronize with internal state
         }
 
+        //- Print description to Ostream
+        virtual void print(Ostream& os) const;
+
 };
 
 

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

@@ -0,0 +1,224 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2016-2017 OpenCFD Ltd.
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+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::memorybuf
+
+Description
+    A std::streambuf used for memory buffer streams such as
+    UIListStream, UOListStream, etc.
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef memoryStreamBuffer_H
+#define memoryStreamBuffer_H
+
+#include "UList.H"
+#include <type_traits>
+#include <sstream>
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+
+/*---------------------------------------------------------------------------*\
+                          Class memorybuf Declaration
+\*---------------------------------------------------------------------------*/
+
+//- A streambuf for memory
+class memorybuf
+:
+    public std::streambuf
+{
+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
+    )
+    {
+        const bool testin  = which & std::ios_base::in;
+        const bool testout = which & std::ios_base::out;
+
+        if (way == std::ios_base::beg)
+        {
+            if (testin)
+            {
+                setg(eback(), eback(), egptr());
+                gbump(off);
+            }
+            if (testout)
+            {
+                setp(pbase(), epptr());
+                pbump(off);
+            }
+        }
+        else if (way == std::ios_base::cur)
+        {
+            if (testin)
+            {
+                gbump(off);
+            }
+            if (testout)
+            {
+                pbump(off);
+            }
+        }
+        else if (way == std::ios_base::end)
+        {
+            if (testin)
+            {
+                setg(eback(), eback(), egptr());
+                gbump(egptr() - eback() - off);
+            }
+            if (testout)
+            {
+                setp(pbase(), epptr());
+                pbump(epptr() - pbase() - off);
+            }
+        }
+
+        if (testin)
+        {
+            return (gptr() - eback()); // tellg()
+        }
+        if (testout)
+        {
+            return (pptr() - pbase()); // tellp()
+        }
+
+        return -1;
+    }
+
+
+    //- Set position pointer to absolute position
+    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);
+    }
+
+
+public:
+
+    // Forward declarations
+    class input;
+    class output;
+};
+
+
+/*---------------------------------------------------------------------------*\
+                      Class memorybuf::input Declaration
+\*---------------------------------------------------------------------------*/
+
+//- An output streambuf for memory access
+class memorybuf::input
+:
+    public memorybuf
+{
+protected:
+
+    //- Get sequence of characters
+    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;
+    }
+
+
+    //- The buffer get position
+    inline std::streamsize tellg() const
+    {
+        return (gptr() - eback());
+    }
+
+    //- Sync get buffer pointers to agree with list dimensions
+    inline void set_gbuffer(UList<char>& list)
+    {
+        setg(list.begin(), list.begin(), list.end());
+    }
+};
+
+
+/*---------------------------------------------------------------------------*\
+                      Class memorybuf::output Declaration
+\*---------------------------------------------------------------------------*/
+
+//- An output streambuf for memory access
+class memorybuf::output
+:
+    public memorybuf
+{
+protected:
+
+    //- Put sequence of characters
+    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;
+    }
+
+    //- The buffer put position
+    inline std::streamsize tellp() const
+    {
+        return (pptr() - pbase());
+    }
+
+    //- Sync put buffer pointers to agree with list dimensions
+    inline void set_pbuffer(UList<char>& list)
+    {
+        setp(list.begin(), list.end());
+    }
+
+};
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //