0029258: Foundation Classes - provide move constructors for string classes

New macro OCCT_NO_RVALUE_REFERENCE is introduced to disable methods using move semantics on obsolete compilers that do not support rvalue references.

TCollection_AsciiString, TCollection_ExtendedString, NCollection_UtfString - added method Swap(), move constructor, and move assignment operator.

Draw command QATestArrayMove is added to test for memory corruption if NCollection_Array1<> bound to local C buffer is returned from function by value.

src/TCollection/TCollection_AsciiString.cxx

@@ -23,9 +23,11 @@
 #include <TCollection_ExtendedString.hxx>
 #include <TCollection_HAsciiString.hxx>
 
+#include <algorithm>
 #include <cctype>
 #include <cstdio>
 #include <cstring>
+
 // Shortcuts to standard allocate and reallocate functions
 static inline Standard_PCharacter Allocate(const Standard_Size aLength)
 {
@@ -416,6 +418,15 @@ void TCollection_AsciiString::Copy(const TCollection_AsciiString& fromwhere)
   }
 }
 
+// ----------------------------------------------------------------------------
+// Swap
+// ----------------------------------------------------------------------------
+void TCollection_AsciiString::Swap (TCollection_AsciiString& theOther)
+{
+  std::swap (mystring, theOther.mystring);
+  std::swap (mylength, theOther.mylength);
+}
+
 // ----------------------------------------------------------------------------
 // Destroy
 // ----------------------------------------------------------------------------

src/TCollection/TCollection_AsciiString.hxx

@@ -80,6 +80,17 @@ public:
   
   //! Initializes a AsciiString with another AsciiString.
   Standard_EXPORT TCollection_AsciiString(const TCollection_AsciiString& astring);
+
+#ifndef OCCT_NO_RVALUE_REFERENCE
+  //! Move constructor
+  Standard_EXPORT TCollection_AsciiString (TCollection_AsciiString&& theOther)
+  : mystring (theOther.mystring),
+    mylength (theOther.mylength)
+  {
+    theOther.mystring = NULL;
+    theOther.mylength = 0;
+  }
+#endif
   
   //! Initializes a AsciiString with copy of another AsciiString
   //! concatenated with the message character.
@@ -270,7 +281,15 @@ void operator = (const TCollection_AsciiString& fromwhere)
 {
   Copy(fromwhere);
 }
-  
+
+  //! Exchange the data of two strings (without reallocating memory).
+  Standard_EXPORT void Swap (TCollection_AsciiString& theOther);
+
+#ifndef OCCT_NO_RVALUE_REFERENCE
+  //! Move assignment operator
+  TCollection_AsciiString& operator= (TCollection_AsciiString&& theOther) { Swap (theOther); return *this; }
+#endif
+
   //! Frees memory allocated by AsciiString.
   Standard_EXPORT ~TCollection_AsciiString();
   

src/TCollection/TCollection_ExtendedString.cxx

@@ -23,6 +23,7 @@
 #include <Standard_OutOfRange.hxx>
 #include <TCollection_AsciiString.hxx>
 
+#include <algorithm>
 #include <cctype>
 #include <cstdio>
 
@@ -373,6 +374,15 @@ void TCollection_ExtendedString::Copy (const TCollection_ExtendedString& fromwhe
   }
 }
 
+// ----------------------------------------------------------------------------
+// Swap
+// ----------------------------------------------------------------------------
+void TCollection_ExtendedString::Swap (TCollection_ExtendedString& theOther)
+{
+  std::swap (mystring, theOther.mystring);
+  std::swap (mylength, theOther.mylength);
+}
+
 // ----------------------------------------------------------------------------
 // Destroy
 // ----------------------------------------------------------------------------

src/TCollection/TCollection_ExtendedString.hxx

@@ -100,7 +100,18 @@ public:
   
   //! Initializes a ExtendedString with another ExtendedString.
   Standard_EXPORT TCollection_ExtendedString(const TCollection_ExtendedString& astring);
-  
+
+#ifndef OCCT_NO_RVALUE_REFERENCE
+  //! Move constructor
+  Standard_EXPORT TCollection_ExtendedString (TCollection_ExtendedString&& theOther)
+  : mystring (theOther.mystring),
+    mylength (theOther.mylength)
+  {
+    theOther.mystring = NULL;
+    theOther.mylength = 0;
+  }
+#endif
+
   //! Creation by converting an Ascii string to an extended
   //! string. The string is treated as having UTF-8 coding.
   //! If it is not a UTF-8 then each character is copied to ExtCharacter.
@@ -140,7 +151,15 @@ void operator = (const TCollection_ExtendedString& fromwhere)
 {
   Copy(fromwhere);
 }
-  
+
+  //! Exchange the data of two strings (without reallocating memory).
+  Standard_EXPORT void Swap (TCollection_ExtendedString& theOther);
+
+#ifndef OCCT_NO_RVALUE_REFERENCE
+  //! Move assignment operator
+  TCollection_ExtendedString& operator= (TCollection_ExtendedString&& theOther) { Swap (theOther); return *this; }
+#endif
+
   //! Frees memory allocated by ExtendedString.
   Standard_EXPORT ~TCollection_ExtendedString();