diff options
author | Luboš Luňák <l.lunak@suse.cz> | 2012-03-28 10:51:45 +0200 |
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committer | Luboš Luňák <l.lunak@suse.cz> | 2012-03-28 10:52:40 +0200 |
commit | 5aa523a61f812a44d6cab926df501d6672e4aeda (patch) | |
tree | bb74514575dd006180d92ceee1196334a319529d /sal | |
parent | ShapeTypeModel::maFlip: correct bogus doxygen comment (diff) | |
download | core-5aa523a61f812a44d6cab926df501d6672e4aeda.tar.gz core-5aa523a61f812a44d6cab926df501d6672e4aeda.zip |
remove (non-const) char[N] overloads introduced because of string literals
Cleaned up SFINAE helper classes and added even more comments.
Diffstat (limited to 'sal')
-rw-r--r-- | sal/inc/rtl/string.hxx | 309 |
1 files changed, 113 insertions, 196 deletions
diff --git a/sal/inc/rtl/string.hxx b/sal/inc/rtl/string.hxx index 0593ddf25eec..39414e64628c 100644 --- a/sal/inc/rtl/string.hxx +++ b/sal/inc/rtl/string.hxx @@ -57,12 +57,10 @@ namespace rtl #ifdef RTL_STRING_UNITTEST #undef rtl -// helper macros to make functions appear more readable +// helper macro to make functions appear more readable #define RTL_STRING_CONST_FUNCTION rtl_string_unittest_const_literal_function = true; -#define RTL_STRING_NON_CONST_FUNCTION rtl_string_unittest_non_const_literal_function = true; #else #define RTL_STRING_CONST_FUNCTION -#define RTL_STRING_NON_CONST_FUNCTION #endif /* ======================================================================= */ @@ -93,10 +91,23 @@ namespace rtl namespace internal { -// This template is used for SFINAE (Substitution failure is not an error), to detect that -// the template types used in the OString ctor actually are only either char* or const char*. -// Using a template appears to be the only way to distinguish char* and char[], since -// using char*(&) does not work with something explicitly cast to char*. +/* +These templates use SFINAE (Substitution failure is not an error) to help distinguish the various +plain C string types: char*, const char*, char[N] and const char[N]. There are 2 cases: +1) Only string literal (i.e. const char[N]) is wanted, not any of the others. + In this case it is necessary to distinguish between const char[N] and char[N], as the latter + would be automatically converted to the const variant, which is not wanted (not a string literal + with known size of the content). In this case ConstCharArrayDetector is used to ensure the function + is called only with const char[N] arguments. There's no other plain C string type overload. +2) All plain C string types are wanted, and const char[N] needs to be handled differently. + In this case const char[N] would match const char* argument type (not exactly sure why, but it's + consistent in all of gcc, clang and msvc). Using a template with a reference to const of the type + avoids this problem, and CharPtrDetector ensures that the function is called only with char pointer + arguments. The const in the argument is necessary to handle the case when something is explicitly + cast to const char*. Additionally (non-const) char[N] needs to be handled, but with the reference + being const, it would also match const char[N], so another overload with a reference to non-const + and NonConstCharArrayDetector are used to ensure the function is called only with (non-const) char[N]. +*/ struct Dummy {}; template< typename T1, typename T2 > struct CharPtrDetector @@ -112,6 +123,29 @@ struct CharPtrDetector< char*, T > { typedef T Type; }; + +template< typename T1, typename T2 > +struct NonConstCharArrayDetector +{ +}; +template< typename T, int N > +struct NonConstCharArrayDetector< char[ N ], T > +{ + typedef T Type; +}; +// This is similar, only it helps to detect const char[]. Without using a template, +// (non-const) char[] would be automatically converted to const char[], which is unwanted +// here (size of the content is not known). +template< typename T1, typename T2 > +struct ConstCharArrayDetector +{ +}; +template< int N, typename T > +struct ConstCharArrayDetector< const char[ N ], T > +{ + typedef T Type; + static const int size = N; +}; } class OString @@ -208,6 +242,13 @@ public: rtl_string_newFromStr( &pData, value ); } + template< typename T > + OString( T& value, typename internal::NonConstCharArrayDetector< T, internal::Dummy >::Type = internal::Dummy() ) SAL_THROW(()) + { + pData = 0; + rtl_string_newFromStr( &pData, value ); + } + /** New string from a string literal. @@ -217,29 +258,16 @@ public: @param literal a string literal */ - template< int N > - OString( const char (&literal)[ N ] ) SAL_THROW(()) + template< typename T > + OString( T& literal, typename internal::ConstCharArrayDetector< T, internal::Dummy >::Type = internal::Dummy() ) SAL_THROW(()) { pData = 0; - rtl_string_newFromLiteral( &pData, literal, N - 1 ); + rtl_string_newFromLiteral( &pData, literal, internal::ConstCharArrayDetector< T, void >::size - 1 ); #ifdef RTL_STRING_UNITTEST rtl_string_unittest_const_literal = true; #endif } - /** - @overload - New string from a non-const char array. - @since LibreOffice 3.6 - - @param value non-const char array - */ - template< int N > - OString( char (&value)[ N ] ) SAL_THROW(()) - { // the array is not const, so its size may not match the string length - 1 - pData = 0; - rtl_string_newFromStr( &pData, value ); - } #endif // HAVE_SFINAE_ANONYMOUS_BROKEN /** @@ -309,25 +337,11 @@ public: This function accepts an ASCII string literal as its argument. @since LibreOffice 3.6 */ - template< int N > - OString& operator=( const char (&literal)[ N ] ) SAL_THROW(()) + template< typename T > + typename internal::ConstCharArrayDetector< T, OString& >::Type operator=( T& literal ) SAL_THROW(()) { RTL_STRING_CONST_FUNCTION - rtl_string_newFromLiteral( &pData, literal, N - 1 ); - return *this; - } - /** - @overload - This function accepts a non-const char array as its argument. - @since LibreOffice 3.6 - - @param value non-const char array - */ - template< int N > - OString& operator=( char (&value)[ N ] ) SAL_THROW(()) - { - rtl_string_newFromStr( &pData, value ); - RTL_STRING_NON_CONST_FUNCTION + rtl_string_newFromLiteral( &pData, literal, internal::ConstCharArrayDetector< T, void >::size - 1 ); return *this; } @@ -543,32 +557,25 @@ public: return rtl_str_compareIgnoreAsciiCase( pData->buffer, asciiStr ) == 0; } + template< typename T > + typename internal::NonConstCharArrayDetector< T, bool >::Type equalsIgnoreAsciiCase( T& asciiStr ) const SAL_THROW(()) + { + return rtl_str_compareIgnoreAsciiCase( pData->buffer, asciiStr ) == 0; + } + /** @overload This function accepts an ASCII string literal as its argument. @since LibreOffice 3.6 */ - template< int N > - bool equalsIgnoreAsciiCase( const char (&literal)[ N ] ) const SAL_THROW(()) + template< typename T > + typename internal::ConstCharArrayDetector< T, bool >::Type equalsIgnoreAsciiCase( T& literal ) const SAL_THROW(()) { RTL_STRING_CONST_FUNCTION - if ( pData->length != N - 1 ) + if ( pData->length != internal::ConstCharArrayDetector< T, void >::size - 1 ) return false; return rtl_str_compareIgnoreAsciiCase_WithLength( pData->buffer, pData->length, - literal, N - 1 ) == 0; - } - /** - @overload - This function accepts a non-const char array as its argument. - @since LibreOffice 3.6 - - @param value non-const char array - */ - template< int N > - bool equalsIgnoreAsciiCase( char (&value)[ N ] ) const SAL_THROW(()) - { - RTL_STRING_NON_CONST_FUNCTION - return rtl_str_compareIgnoreAsciiCase( pData->buffer, value ) == 0; + literal, internal::ConstCharArrayDetector< T, void >::size - 1 ) == 0; } /** @@ -625,29 +632,13 @@ public: This function accepts an ASCII string literal as its argument. @since LibreOffice 3.6 */ - template< int N > - bool match( const char (&literal)[ N ], sal_Int32 fromIndex = 0 ) const SAL_THROW(()) + template< typename T > + typename internal::ConstCharArrayDetector< T, bool >::Type match( T& literal, sal_Int32 fromIndex = 0 ) const SAL_THROW(()) { RTL_STRING_CONST_FUNCTION return rtl_str_shortenedCompare_WithLength( pData->buffer + fromIndex, pData->length - fromIndex, - literal, N - 1, N - 1) == 0; - } - /** - @overload - This function accepts a non-const char array as its argument. - @since LibreOffice 3.6 - - @param value non-const char array - */ - template< int N > - bool match( char (&value)[ N ], sal_Int32 fromIndex = 0 ) const SAL_THROW(()) - { - RTL_STRING_NON_CONST_FUNCTION - sal_Int32 strLength = rtl_str_getLength( value ); - return rtl_str_shortenedCompare_WithLength( - pData->buffer + fromIndex, pData->length - fromIndex, - value, strLength, strLength) == 0; + literal, internal::ConstCharArrayDetector< T, void >::size - 1, internal::ConstCharArrayDetector< T, void >::size - 1) == 0; } /** @@ -713,27 +704,12 @@ public: This function accepts an ASCII string literal as its argument. @since LibreOffice 3.6 */ - template< int N > - bool matchIgnoreAsciiCase( const char (&literal)[ N ], sal_Int32 fromIndex = 0 ) const + template< typename T > + typename internal::ConstCharArrayDetector< T, bool >::Type matchIgnoreAsciiCase( T& literal, sal_Int32 fromIndex = 0 ) const { RTL_STRING_CONST_FUNCTION return rtl_str_shortenedCompareIgnoreAsciiCase_WithLength( pData->buffer+fromIndex, pData->length-fromIndex, - literal, N - 1, N - 1 ) == 0; - } - /** - @overload - This function accepts a non-const char array as its argument. - @since LibreOffice 3.6 - - @param value non-const char array - */ - template< int N > - bool matchIgnoreAsciiCase( char (&value)[ N ], sal_Int32 fromIndex = 0 ) const - { - RTL_STRING_NON_CONST_FUNCTION - sal_Int32 strLength = rtl_str_getLength( value ); - return rtl_str_shortenedCompareIgnoreAsciiCase_WithLength( pData->buffer+fromIndex, pData->length-fromIndex, - value, strLength, strLength ) == 0; + literal, internal::ConstCharArrayDetector< T, void >::size - 1, internal::ConstCharArrayDetector< T, void >::size - 1 ) == 0; } /** @@ -756,27 +732,12 @@ public: This function accepts an ASCII string literal as its argument. @since LibreOffice 3.6 */ - template< int N > - bool endsWith( const char (&literal)[ N ] ) const + template< typename T > + typename internal::ConstCharArrayDetector< T, bool >::Type endsWith( T& literal ) const { RTL_STRING_CONST_FUNCTION - return N - 1 <= getLength() - && match(literal, getLength() - ( N - 1 )); - } - /** - @overload - This function accepts a non-const char array as its argument. - @since LibreOffice 3.6 - - @param value non-const char array - */ - template< int N > - bool endsWith( char (&value)[ N ] ) const - { - RTL_STRING_NON_CONST_FUNCTION - sal_Int32 strLength = rtl_str_getLength( value ); - return strLength <= getLength() - && matchL(value, strLength, getLength() - strLength); + return internal::ConstCharArrayDetector< T, void >::size - 1 <= getLength() + && match(literal, getLength() - ( internal::ConstCharArrayDetector< T, void >::size - 1 )); } /** @@ -817,36 +778,35 @@ public: } template< typename T > + friend typename internal::NonConstCharArrayDetector< T, bool >::Type operator==( const OString& rStr1, T& value ) SAL_THROW(()) + { + return rStr1.compareTo( value ) == 0; + } + + template< typename T > friend typename internal::CharPtrDetector< T, bool >::Type operator==( const T& value, const OString& rStr2 ) SAL_THROW(()) { return rStr2.compareTo( value ) == 0; } + template< typename T > + friend typename internal::NonConstCharArrayDetector< T, bool >::Type operator==( T& value, const OString& rStr2 ) SAL_THROW(()) + { + return rStr2.compareTo( value ) == 0; + } + /** @overload This function accepts an ASCII string literal as its argument. @since LibreOffice 3.6 */ - template< int N > - friend bool operator == ( const OString& rStr, const char (&literal)[ N ] ) SAL_THROW(()) + template< typename T > + friend typename internal::ConstCharArrayDetector< T, bool >::Type operator==( const OString& rStr, T& literal ) SAL_THROW(()) { RTL_STRING_CONST_FUNCTION - return rStr.getLength() == N - 1 - && rtl_str_compare_WithLength( rStr.pData->buffer, rStr.pData->length, literal, N - 1 ) == 0; - } - - /** - @overload - This function accepts a non-const char array as its argument. - @since LibreOffice 3.6 - - @param value non-const char array - */ - template< int N > - friend bool operator == ( const OString& rStr, char (&value)[ N ] ) SAL_THROW(()) - { - RTL_STRING_NON_CONST_FUNCTION - return rStr.compareTo( value ) == 0; + return rStr.getLength() == internal::ConstCharArrayDetector< T, void >::size - 1 + && rtl_str_compare_WithLength( rStr.pData->buffer, rStr.pData->length, literal, + internal::ConstCharArrayDetector< T, void >::size - 1 ) == 0; } /** @@ -854,30 +814,23 @@ public: This function accepts an ASCII string literal as its argument. @since LibreOffice 3.6 */ - template< int N > - friend bool operator == ( const char (&literal)[ N ], const OString& rStr ) SAL_THROW(()) + template< typename T > + friend typename internal::ConstCharArrayDetector< T, bool >::Type operator==( T& literal, const OString& rStr ) SAL_THROW(()) { RTL_STRING_CONST_FUNCTION - return rStr.getLength() == N - 1 - && rtl_str_compare_WithLength( rStr.pData->buffer, rStr.pData->length, literal, N - 1 ) == 0; + return rStr.getLength() == internal::ConstCharArrayDetector< T, void >::size - 1 + && rtl_str_compare_WithLength( rStr.pData->buffer, rStr.pData->length, literal, + internal::ConstCharArrayDetector< T, void >::size - 1 ) == 0; } - /** - @overload - This function accepts a non-const char array as its argument. - @since LibreOffice 3.6 - - @param value non-const char array - */ - template< int N > - friend bool operator == ( char (&value)[ N ], const OString& rStr ) SAL_THROW(()) + template< typename T > + friend typename internal::CharPtrDetector< T, bool >::Type operator!=( const OString& rStr1, const T& value ) SAL_THROW(()) { - RTL_STRING_NON_CONST_FUNCTION - return rStr.compareTo( value ) == 0; + return !(operator == ( rStr1, value )); } template< typename T > - friend typename internal::CharPtrDetector< T, bool >::Type operator!=( const OString& rStr1, const T& value ) SAL_THROW(()) + friend typename internal::NonConstCharArrayDetector< T, bool >::Type operator!=( const OString& rStr1, T& value ) SAL_THROW(()) { return !(operator == ( rStr1, value )); } @@ -888,55 +841,35 @@ public: return !(operator == ( value, rStr2 )); } + template< typename T > + friend typename internal::NonConstCharArrayDetector< T, bool >::Type operator!=( T& value, const OString& rStr2 ) SAL_THROW(()) + { + return !(operator == ( value, rStr2 )); + } + /** @overload This function accepts an ASCII string literal as its argument. @since LibreOffice 3.6 */ - template< int N > - friend bool operator != ( const OString& rStr, const char (&literal)[ N ] ) SAL_THROW(()) + template< typename T > + friend typename internal::ConstCharArrayDetector< T, bool >::Type operator!=( const OString& rStr, T& literal ) SAL_THROW(()) { return !( rStr == literal ); } /** - @overload - This function accepts a non-const char array as its argument. - @since LibreOffice 3.6 - - @param value non-const char array - */ - template< int N > - friend bool operator != ( const OString& rStr, char (&value)[ N ] ) SAL_THROW(()) - { - return !( rStr == value ); - } - - /** @overload This function accepts an ASCII string literal as its argument. @since LibreOffice 3.6 */ - template< int N > - friend bool operator != ( const char (&literal)[ N ], const OString& rStr ) SAL_THROW(()) + template< typename T > + friend typename internal::ConstCharArrayDetector< T, bool >::Type operator!=( T& literal, const OString& rStr ) SAL_THROW(()) { return !( literal == rStr ); } /** - @overload - This function accepts a non-const char array as its argument. - @since LibreOffice 3.6 - - @param value non-const char array - */ - template< int N > - friend bool operator != ( char (&value)[ N ], const OString& rStr ) SAL_THROW(()) - { - return !( value == rStr ); - } - - /** Returns a hashcode for this string. @return a hash code value for this object. @@ -1025,28 +958,12 @@ public: This function accepts an ASCII string literal as its argument. @since LibreOffice 3.6 */ - template< int N > - sal_Int32 indexOf( const char (&literal)[ N ], sal_Int32 fromIndex = 0 ) const SAL_THROW(()) + template< typename T > + typename internal::ConstCharArrayDetector< T, sal_Int32 >::Type indexOf( T& literal, sal_Int32 fromIndex = 0 ) const SAL_THROW(()) { RTL_STRING_CONST_FUNCTION sal_Int32 n = rtl_str_indexOfStr_WithLength( - pData->buffer + fromIndex, pData->length - fromIndex, literal, N - 1); - return n < 0 ? n : n + fromIndex; - } - - /** - @overload - This function accepts a non-const char array as its argument. - @since LibreOffice 3.6 - - @param value non-const char array - */ - template< int N > - sal_Int32 indexOf( char (&value)[ N ], sal_Int32 fromIndex = 0 ) const SAL_THROW(()) - { - RTL_STRING_NON_CONST_FUNCTION - sal_Int32 n = rtl_str_indexOfStr_WithLength( - pData->buffer + fromIndex, pData->length - fromIndex, value, rtl_str_getLength( value )); + pData->buffer + fromIndex, pData->length - fromIndex, literal, internal::ConstCharArrayDetector< T, void >::size - 1); return n < 0 ? n : n + fromIndex; } |