ENH: additional startsWith(), endsWith() string methods

- As the names describe, check if the string starts or ends with a
  particular value. Always true if the given text is empty or if the
  string is identical to the given text.

applications/test/string/Test-string.C

@@ -34,6 +34,8 @@ Description
 #include "int.H"
 #include "uint.H"
 #include "scalar.H"
+#include "Switch.H"
+#include "stringList.H"
 
 using namespace Foam;
 
@@ -166,6 +168,76 @@ int main(int argc, char *argv[])
             << Foam::name("formatted >%08d<", val) << "\n";
     }
 
+    // test startsWith, endsWith methods
+    {
+        string empty; //;
+        string input1 = "shorter input";
+        string input2 = "longer input text";
+
+        stringList checks{"match", "long", "", "short", "text", "s", "l", "t"};
+
+        Info<< nl;
+        Info<< "check startsWith:" << nl
+            << "~~~~~~~~~~~~~~~~~" << nl;
+
+        Info<<"input: " << empty << nl;
+        for (const string& test : checks)
+        {
+            Info<< "    startsWith(" << test << ") = "
+                << Switch(empty.startsWith(test)) << nl;
+        }
+        Info<<"input: " << input1 << nl;
+        for (const string& test : checks)
+        {
+            Info<< "    startsWith(" << test << ") = "
+                << Switch(input1.startsWith(test)) << nl;
+        }
+        Info<<"input: " << input2 << nl;
+        for (const string& test : checks)
+        {
+            Info<< "    startsWith(" << test << ") = "
+                << Switch(input2.startsWith(test)) << nl;
+        }
+
+
+        Info<< nl;
+        Info<< "check endsWith:" << nl
+            << "~~~~~~~~~~~~~~~~~" << nl;
+
+        Info<<"input: " << empty << nl;
+        for (const string& test : checks)
+        {
+            Info<< "    endsWith(" << test << ") = "
+                << Switch(empty.endsWith(test)) << nl;
+        }
+        Info<<"input: " << input1 << nl;
+        for (const string& test : checks)
+        {
+            Info<< "    endsWith(" << test << ") = "
+                << Switch(input1.endsWith(test)) << nl;
+        }
+        Info<<"input: " << input2 << nl;
+        for (const string& test : checks)
+        {
+            Info<< "    endsWith(" << test << ") = "
+                << Switch(input2.endsWith(test)) << nl;
+        }
+
+        Info<< nl;
+        Info<< "check endsWith as applied to field names:" << nl
+            << "~~~~~~~~~~~~~~~~~" << nl;
+
+        string input3 = "field_0";
+        string input4 = "_0";
+
+        Info<<input3 << " endsWith(\"_0\") = "
+            << Switch(input3.endsWith("_0")) << nl;
+
+        Info<<input4 << " endsWith(\"_0\") = "
+            << Switch(input4.endsWith("_0")) << nl;
+    }
+
+
     Info<< "\nEnd\n" << endl;
     return 0;
 }

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

@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2016 OpenFOAM Foundation
-     \\/     M anipulation  |
+     \\/     M anipulation  | Copyright (C) 2016 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -26,7 +26,6 @@ License
 #include "string.H"
 #include "stringOps.H"
 
-
 /* * * * * * * * * * * * * * * Static Member Data  * * * * * * * * * * * * * */
 
 const char* const Foam::string::typeName = "string";
@@ -168,4 +167,30 @@ Foam::string Foam::string::removeTrailing(const char character) const
 }
 
 
+bool Foam::string::startsWith(const std::string& text) const
+{
+    const size_type strLen = this->size();
+    const size_type txtLen = text.size();
+
+    return
+    (
+        !txtLen
+     || (strLen >= txtLen && !compare(0, txtLen, text))
+    );
+}
+
+
+bool Foam::string::endsWith(const std::string& text) const
+{
+    const size_type strLen = this->size();
+    const size_type txtLen = text.size();
+
+    return
+    (
+        !txtLen
+     || (strLen >= txtLen && !compare(strLen - txtLen, npos, text))
+    );
+}
+
+
 // ************************************************************************* //

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  |
+     \\/     M anipulation  | Copyright (C) 2016 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -104,49 +104,53 @@ public:
         inline string();
 
         //- Construct from std::string
-        inline string(const std::string&);
+        inline string(const std::string& str);
 
         //- Construct as copy of character array
-        inline string(const char*);
+        inline string(const char* str);
 
         //- Construct as copy of specified number of characters
-        inline string(const char*, const size_type);
+        inline string(const char* str, const size_type len);
 
         //- Construct from a single character
-        inline string(const char);
+        inline string(const char c);
 
         //- Construct from Istream
-        string(Istream&);
+        string(Istream& is);
 
 
     // Member Functions
 
         //- Count and return the number of a given character in the string
-        size_type count(const char) const;
+        size_type count(const char c) const;
 
         //- Is this string type valid?
         template<class String>
-        static inline bool valid(const string&);
+        static inline bool valid(const string& str);
 
         //- Does this string have particular meta-characters?
         //  The meta characters can be optionally quoted.
         template<class String>
-        static inline bool meta(const string&, const char quote='\\');
+        static inline bool meta(const string& str, const char quote = '\\');
 
         //- Strip invalid characters from the given string
         template<class String>
-        static inline bool stripInvalid(string&);
+        static inline bool stripInvalid(string& str);
 
         //- Return a valid String from the given string
         template<class String>
-        static inline String validate(const string&);
+        static inline String validate(const string& str);
 
         //- Return a String with quoted meta-characters from the given string
         template<class String>
-        static inline string quotemeta(const string&, const char quote='\\');
+        static inline string quotemeta
+        (
+            const string& str,
+            const char quote = '\\'
+        );
 
         //- True when strings match literally
-        inline bool match(const std::string&) const;
+        inline bool match(const std::string& str) const;
 
         //- Avoid masking the normal std::string replace
         using std::string::replace;
@@ -186,16 +190,26 @@ public:
         string& expand(const bool allowEmpty = false);
 
         //- Remove repeated characters returning true if string changed
-        bool removeRepeated(const char);
+        bool removeRepeated(const char character);
 
         //- Return string with repeated characters removed
-        string removeRepeated(const char) const;
+        string removeRepeated(const char character) const;
 
         //- Remove trailing character returning true if string changed
-        bool removeTrailing(const char);
+        bool removeTrailing(const char character);
 
         //- Return string with trailing character removed
-        string removeTrailing(const char) const;
+        string removeTrailing(const char character) const;
+
+        //- True if the string starts with the given text.
+        //  Always true if the given text is empty or if the string
+        //  is identical to the given text.
+        bool startsWith(const std::string& text) const;
+
+        //- True if the string ends with the given text.
+        //  Always true if the given text is empty or if the string
+        //  is identical to the given text.
+        bool endsWith(const std::string& text) const;
 
 
     // Member Operators
@@ -216,8 +230,8 @@ public:
 
     // IOstream Operators
 
-        friend Istream& operator>>(Istream&, string&);
-        friend Ostream& operator<<(Ostream&, const string&);
+        friend Istream& operator>>(Istream& is, string& s);
+        friend Ostream& operator<<(Ostream& os, const string& s);
 };