ENH: update and enhancement of memory-streams

- soft renames (ie, old names still available via typedefs) for more
  reasonable names and more coverage with std stream variants.

  The old names could be a bit cryptic.
  For example, uiliststream (== an unallocated/external list storage),
  which is written as std::ispanstream for C++23.

  Could similarly argue that IListStream is better named as
  ICharStream, since it is an input stream of characters and the
  internal storage mechanism (List or something else) is mostly
  irrelevant.

  Extending the coverage to include all std stream variants, and
  simply rewrap them for OpenFOAM IOstream types. This simplifies the
  inheritance patterns and allows reuse of icharstream/ocharstream as
  a drop-in replace for istringstream/ostringstream in other wrappers.

  Classes:
    * icharstream / ICharStream   [old: none / IListStream]
    * ocharstream / OCharStream   [old: none / OListStream]
    * ispanstream / ISpanStream   [old: uiliststream / UIListStream]
    * ospanstream / OSpanStream   [old: none / UOListStream]

  Possible new uses : read file contents into a buffer, broadcast
  buffer contents to other ranks and then transfer into an icharstream
  to be read from. This avoid the multiple intermediate copies that
  would be associated when using an istringstream.

- Use size doubling instead of block-wise incremental for ocharstream
  (OCharStream). This corresponds to the sizing behaviour as per
  std::stringstream (according to gcc-11 includes)

STYLE: drop Foam_IOstream_extras constructors for memory streams

- transitional/legacy constructors but not used in any code

applications/test/SpanStream1/Make/files

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

applications/test/SpanStream1/Make/options

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

applications/test/SpanStream1/Test-SpanStream1.C

@@ -0,0 +1,236 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  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/>.
+
+Description
+
+\*---------------------------------------------------------------------------*/
+
+#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 << '"';
+    for (const char c : list)
+    {
+        os << c;
+    }
+    os << '"';
+
+    return os;
+}
+
+
+Ostream& toString(Ostream& os, const std::vector<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;
+}
+
+
+template<>
+void printInfo(const UList<char>& buf)
+{
+    Info<< nl << "=========================" << endl;
+    toString(Info, buf);
+    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(1000);
+
+    OSpanStream obuf(storage);
+    obuf << 1002 << "\n" << "abcd" << "\n" << "def" << "\n" << 3.14159 << ";\n";
+
+    obuf.print(Info);
+
+    // Match size
+    storage.resize(obuf.size());
+
+    Info<<"as string: " << string(storage.cdata(), storage.size()) << endl;
+
+    // Attach input buffer - could also do without previous resize
+    {
+        ISpanStream ibuf(storage);
+
+        printTokens(ibuf);
+
+        Info<< nl << "Repeat..." << endl;
+        ibuf.rewind();
+
+        printTokens(ibuf);
+    }
+
+
+    // Attach input buffer - could also do without previous resize
+    {
+        Info<< "parse as std::istream\n";
+
+        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;
+
+        is.rewind();
+        while (std::getline(is, tok))
+        {
+            std::cerr << "tok: " << tok << nl;
+        }
+    }
+
+
+    // Simple test using stl items only
+    {
+        std::vector<char> chars;
+        chars.reserve(1024);
+
+        for (int i=0; i < 10; ++i)
+        {
+            chars.push_back('A' + i);
+            chars.push_back('0' + i);
+            chars.push_back('\n');
+        }
+
+        Info<< "parse std::vector of char: ";
+        toString(Info, chars);
+        Info<< "----" << nl;
+
+        ispanstream is(chars.data(), chars.size());
+        string tok;
+        std::cerr<< nl << "Parsed..." << nl;
+        while (std::getline(is, tok))
+        {
+            std::cerr << "tok: " << tok << nl;
+        }
+
+        Info<< nl << "Repeat..." << endl;
+
+        is.rewind();
+        while (std::getline(is, tok))
+        {
+            std::cerr << "tok: " << tok << nl;
+        }
+    }
+
+    Info<< "\nEnd\n" << endl;
+
+    return 0;
+}
+
+
+// ************************************************************************* //