ENH: increase some string_view coverage

- remove some stdFoam::span<char> handling, which was just a stop-gap
  measure

applications/test/string_view1/Test-string_view1.cxx

@@ -59,11 +59,6 @@ int main(int argc, char *argv[])
                 << " type: " << typeid(cstr).name() << " len:" << len << nl;
 
             Info<< "    view: " << std::string_view(cstr) << nl;
-
-            Info<< "    span: "
-                << stdFoam::span<const char>(cstr, len) << nl;
-            Info<< "    span: "
-                << stdFoam::span<char>(const_cast<char*>(cstr), len) << nl;
         }
     }
 

src/OpenFOAM/db/IOstreams/IOstreams/Ostream.H

@@ -341,22 +341,6 @@ inline Ostream& operator<<(Ostream& os, std::string_view s)
     return os;
 }
 
-//- Write operator for character span. Output like string data
-inline Ostream& operator<<(Ostream& os, stdFoam::span<char> s)
-{
-    os.writeQuoted(s.data(), s.size(), true);  // quoted
-    os.check("Foam::operator<<(Ostream&, stdFoam::span<char>)");
-    return os;
-}
-
-//- Write operator for const character span. Output like string data
-inline Ostream& operator<<(Ostream& os, stdFoam::span<const char> s)
-{
-    os.writeQuoted(s.data(), s.size(), true);  // quoted
-    os.check("Foam::operator<<(Ostream&, stdFoam::span<const char>)");
-    return os;
-}
-
 
 /*---------------------------------------------------------------------------*\
                        Manipulators (without arguments)

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

@@ -95,10 +95,12 @@ Foam::tokenList Foam::ITstream::parse_chars
     IOstreamOption streamOpt
 )
 {
-    ISpanStream is(s, nbytes, streamOpt);
-
     tokenList tokens;
+    if (s && nbytes > 0)  // extra safety
+    {
+        ISpanStream is(s, nbytes, streamOpt);
         parseStream(is, tokens);
+    }
     return tokens;
 }
 
@@ -107,10 +109,19 @@ Foam::tokenList Foam::ITstream::parse_chars
 
 void Foam::ITstream::reset(const char* input, size_t nbytes)
 {
+    tokenList tokens;
+    if (input && nbytes > 0)  // extra safety
+    {
         ISpanStream is(input, nbytes, static_cast<IOstreamOption>(*this));
 
         parseStream(is, static_cast<tokenList&>(*this));
         ITstream::seek(0);  // rewind() bypassing virtual
+    }
+    else
+    {
+        ITstream::seek(0);  // rewind() bypassing virtual
+        tokenList::clear();
+    }
 }
 
 
@@ -248,7 +259,10 @@ Foam::ITstream::ITstream
 :
     ITstream(streamOpt, name)
 {
+    if (input)
+    {
         reset(input, strlen(input));
+    }
 }
 
 

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

@@ -77,7 +77,8 @@ class ITstream
         //  but leave any excess capacity (ie, like reserve).
         void reserveCapacity(const label newCapacity);
 
-        //- Convert input sequence into a list of tokens,
+        //- Convert input sequence into a list of tokens.
+        //  Includes nullptr guard
         static tokenList parse_chars
         (
             const char* s,
@@ -87,6 +88,7 @@ class ITstream
 
         //- Convert input sequence into a list of tokens,
         //- using the existing stream format. Rewinds the stream
+        //  Includes nullptr guard
         void reset(const char* input, size_t nbytes);
 
         //- Failsafe read-access to token at specified location
@@ -175,32 +177,6 @@ public:
             reset(s.data(), s.size());
         }
 
-        //- Construct token list by parsing the input character sequence
-        //  Uses static parse function internally.
-        explicit ITstream
-        (
-            stdFoam::span<char> s,
-            IOstreamOption streamOpt = IOstreamOption()
-        )
-        :
-            ITstream(streamOpt)
-        {
-            reset(s.data(), s.size());
-        }
-
-        //- Construct token list by parsing the input character sequence
-        //  Uses static parse function internally.
-        explicit ITstream
-        (
-            stdFoam::span<const char> s,
-            IOstreamOption streamOpt = IOstreamOption()
-        )
-        :
-            ITstream(streamOpt)
-        {
-            reset(s.data(), s.size());
-        }
-
 
     // Additional constructors
 
@@ -255,17 +231,6 @@ public:
             return parse_chars(input.cdata(), input.size(), streamOpt);
         }
 
-        //- Create token list by parsing the input string
-        //- until no good tokens remain.
-        static tokenList parse
-        (
-            const std::string& input,
-            IOstreamOption streamOpt = IOstreamOption()
-        )
-        {
-            return parse_chars(input.data(), input.size(), streamOpt);
-        }
-
         //- Create token list by parsing the input character sequence
         //- until no good tokens remain.
         static tokenList parse
@@ -273,9 +238,16 @@ public:
             const char* input,
             IOstreamOption streamOpt = IOstreamOption()
         )
+        {
+            if (input)
             {
                 return parse_chars(input, strlen(input), streamOpt);
             }
+            else
+            {
+                return tokenList();
+            }
+        }
 
         //- Create token list by parsing the input character sequence
         //- until no good tokens remain.
@@ -288,28 +260,6 @@ public:
             return parse_chars(s.data(), s.size(), streamOpt);
         }
 
-        //- Create token list by parsing the input character sequence
-        //- until no good tokens remain.
-        static tokenList parse
-        (
-            stdFoam::span<char> s,
-            IOstreamOption streamOpt = IOstreamOption()
-        )
-        {
-            return parse_chars(s.data(), s.size(), streamOpt);
-        }
-
-        //- Create token list by parsing the input character sequence
-        //- until no good tokens remain.
-        static tokenList parse
-        (
-            stdFoam::span<const char> s,
-            IOstreamOption streamOpt = IOstreamOption()
-        )
-        {
-            return parse_chars(s.data(), s.size(), streamOpt);
-        }
-
 
     // Member Functions
 
@@ -387,7 +337,7 @@ public:
         label& tokenIndex() noexcept { return tokenIndex_; }
 
         //- Set the token index (no checks). \return the previous value
-        label tokenIndex(const label num) noexcept
+        label tokenIndex(label num) noexcept
         {
             label old(tokenIndex_);
             tokenIndex_ = num;

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

@@ -123,20 +123,6 @@ public:
             stream_type(static_cast<buffer_type*>(this))
         {}
 
-        //- Construct (shallow copy) from span character content
-        explicit ispanstream(stdFoam::span<char> s)
-        :
-            buffer_type(const_cast<char*>(s.data()), s.size()),
-            stream_type(static_cast<buffer_type*>(this))
-        {}
-
-        //- Construct (shallow copy) from span character content
-        explicit ispanstream(stdFoam::span<const char> s)
-        :
-            buffer_type(const_cast<char*>(s.data()), s.size()),
-            stream_type(static_cast<buffer_type*>(this))
-        {}
-
 
     // Member Functions
 
@@ -325,26 +311,6 @@ public:
             ISpanStream(buffer.cdata(), buffer.size(), streamOpt)
         {}
 
-        //- Construct (shallow copy) from span character content
-        explicit ISpanStream
-        (
-            stdFoam::span<const char> s,
-            IOstreamOption streamOpt = IOstreamOption()
-        )
-        :
-            ISpanStream(s.data(), s.size(), streamOpt)
-        {}
-
-        //- Construct (shallow copy) from span character content
-        explicit ISpanStream
-        (
-            stdFoam::span<char> s,
-            IOstreamOption streamOpt = IOstreamOption()
-        )
-        :
-            ISpanStream(s.data(), s.size(), streamOpt)
-        {}
-
 
     // Member Functions
 
@@ -402,20 +368,6 @@ public:
             syncState();
         }
 
-        //- Reset input area to use data from span character content
-        void reset(stdFoam::span<char> s)
-        {
-            stream_.reset(s.data(), s.size());
-            syncState();
-        }
-
-        //- Reset input area to use data from span character content
-        void reset(stdFoam::span<const char> s)
-        {
-            stream_.reset(s.data(), s.size());
-            syncState();
-        }
-
         //- Rewind the stream, clearing any old errors
         virtual void rewind() override
         {

src/OpenFOAM/primitives/strings/lists/CStringList.H

@@ -58,6 +58,8 @@ Description
 
 #include <algorithm>  // std::copy
 #include <utility>    // std::initializer_list
+#include <vector>
+#include <string_view>
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
@@ -93,6 +95,11 @@ class CStringList
         //  \return location one-past end of dest (ie, the next destination)
         static inline char* stringCopy(char* dest, const char* src);
 
+        //- Copy string characters into dest as NUL-terminated string.
+        //
+        //  \return location one-past end of dest (ie, the next destination)
+        static inline char* stringCopy(char *dest, std::string_view src);
+
         //- Copy string characters into dest as NUL-terminated string.
         //  Forces conversion of std::sub_match to string form
         //
@@ -133,9 +140,17 @@ public:
         template<class StringType>
         inline explicit CStringList(const UList<StringType>& input);
 
+        //- Copy construct from a list of string_views
+        //  Copies the input characters.
+        inline explicit CStringList(const UList<std::string_view>& input);
+
+        //- Copy construct from a list of string_views
+        //  Copies the input characters.
+        inline explicit CStringList(const std::vector<std::string_view>& input);
+
         //- Copy construct from a list of sub-string references
         //  Copies the input characters.
-        explicit CStringList(const SubStrings& input);
+        inline explicit CStringList(const SubStrings& input);
 
 
     //- Destructor. Invokes clear() to free memory.
@@ -157,6 +172,9 @@ public:
         //- Return the number of C-strings (ie, argc)
         int size() const noexcept { return argc_; }
 
+        //- The flattened character content, with interspersed nul-chars
+        inline std::string_view view() const;
+
         //- The flattened character content, with interspersed nul-chars
         const char* cdata_bytes() const noexcept { return data_; }
 

src/OpenFOAM/primitives/strings/lists/CStringList.cxx

@@ -28,16 +28,6 @@ License
 #include "CStringList.H"
 #include "Ostream.H"
 
-// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
-
-Foam::CStringList::CStringList(const SubStrings& input)
-:
-    CStringList()
-{
-    resetContent(input);
-}
-
-
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
 // Largely identical to resetContent() except with 'c-string'

src/OpenFOAM/primitives/strings/lists/CStringListI.H

@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2016-2024 OpenCFD Ltd.
+    Copyright (C) 2016-2025 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -35,6 +35,14 @@ inline char* Foam::CStringList::stringCopy(char* dest, const char* src)
 }
 
 
+inline char* Foam::CStringList::stringCopy(char *dest, std::string_view src)
+{
+    dest = std::copy_n(src.data(), src.size(), dest);
+    *(dest++) = '\0';
+    return dest;
+}
+
+
 inline char* Foam::CStringList::stringCopy(char *dest, const std::string& src)
 {
     dest = std::copy_n(src.data(), src.size(), dest);
@@ -90,6 +98,33 @@ inline Foam::CStringList::CStringList(const UList<StringType>& input)
 }
 
 
+inline Foam::CStringList::CStringList(const UList<std::string_view>& input)
+:
+    CStringList()
+{
+    resetContent(input);
+}
+
+
+inline Foam::CStringList::CStringList
+(
+    const std::vector<std::string_view>& input
+)
+:
+    CStringList()
+{
+    resetContent(input);
+}
+
+
+inline Foam::CStringList::CStringList(const SubStrings& input)
+:
+    CStringList()
+{
+    resetContent(input);
+}
+
+
 // * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
 
 inline Foam::CStringList::~CStringList()
@@ -100,6 +135,12 @@ inline Foam::CStringList::~CStringList()
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
+inline std::string_view Foam::CStringList::view() const
+{
+    return std::string_view(data_, nbytes_);
+}
+
+
 inline void Foam::CStringList::clear()
 {
     argc_ = 0;