STYLE: two-parameter Foam::name replaced by word::printf (issue #724)

- reduces some ambiguity and clarifies the expected output and
  behaviour.

STYLE: reduce some automatic conversions of char to string

src/OpenFOAM/primitives/strings/string/string.H

@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2016 OpenFOAM Foundation
-     \\/     M anipulation  | Copyright (C) 2016-2017 OpenCFD Ltd.
+     \\/     M anipulation  | Copyright (C) 2016-2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -39,6 +39,7 @@ See also
 SourceFiles
     string.C
     stringIO.C
+    stringTemplates.C
 
 \*---------------------------------------------------------------------------*/
 
@@ -90,6 +91,24 @@ protected:
         //  A wrapped version of find_last_of("./") with additional logic.
         inline std::string::size_type find_ext() const;
 
+        //- A printf-style formatter for a primitive.
+        template<class PrimitiveType>
+        static std::string::size_type string_printf
+        (
+            std::string& output,
+            const char* fmt,
+            const PrimitiveType& val
+        );
+
+        //- A printf-style formatter for a primitive.
+        template<class PrimitiveType>
+        static std::string::size_type string_printf
+        (
+            std::string& output,
+            const std::string& fmt,
+            const PrimitiveType& val
+        );
+
         //- Return file name extension (part after last .)
         word ext() const;
 
@@ -128,8 +147,7 @@ public:
     class hash
     {
     public:
-        hash()
-        {}
+        hash() = default;
 
         //- Hash for string.
         //  Uses Foam::string instead of std::string for automatic conversions.
@@ -152,9 +170,9 @@ public:
         inline string(const char* str, const size_type len);
 
         //- Construct from a single character
-        inline string(const char c);
+        inline explicit string(const char c);
 
-        //- Construct from copies of a single character
+        //- Construct fill copies of a single character
         inline string(const size_type len, const char c);
 
         //- Move construct from std::string
@@ -292,6 +310,10 @@ public:
 
 #include "stringI.H"
 
+#ifdef NoRepository
+    #include "stringTemplates.C"
+#endif
+
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
 #endif

src/OpenFOAM/primitives/strings/string/stringI.H

@@ -23,7 +23,6 @@ License
 
 \*---------------------------------------------------------------------------*/
 
-
 // * * * * * * * * * * * * Protected Member Functions  * * * * * * * * * * * //
 
 inline std::string::size_type Foam::string::find_ext(const std::string& str)
@@ -68,6 +67,8 @@ inline bool Foam::string::removeExt()
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
 inline Foam::string::string()
+:
+    std::string()
 {}
 
 

src/OpenFOAM/primitives/strings/string/stringTemplates.C

@@ -0,0 +1,72 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2018 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 <cstdio>
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+// Could also consider generalizing with C++11 variadic templates
+
+template<class PrimitiveType>
+std::string::size_type Foam::string::string_printf
+(
+    std::string& output,
+    const char* fmt,
+    const PrimitiveType& val
+)
+{
+    // Use snprintf with zero to establish the size (without '\0') required
+    int n = ::snprintf(nullptr, 0, fmt, val);
+    if (n > 0)
+    {
+        output.resize(n+1);
+        char* buf = &(output[0]);
+
+        // Print directly into buffer, no stripping desired
+        n = ::snprintf(buf, n+1, fmt, val);
+        output.resize(n);
+    }
+    else
+    {
+        output.clear();
+    }
+
+    return output.size();
+}
+
+
+template<class PrimitiveType>
+std::string::size_type Foam::string::string_printf
+(
+    std::string& output,
+    const std::string& fmt,
+    const PrimitiveType& val
+)
+{
+    return string_printf(output, fmt.c_str(), val);
+}
+
+
+// ************************************************************************* //