I've been careful to supply only conversion facillities and not try + *
I've been careful to supply only conversion facilities and not try * and duplicate wxString() with many member functions. In the end it is * to be a std::string. There are multiple ways to create text into a std::string - * without the need of member functions. std::ostringstream. + * without the need of too many member functions: + * + *
Because this class used no virtuals, it should be possible to cast any * std::string into a UTF8 using this kind of cast: (UTF8 &) without construction - * or copying being the effect of the cast. + * or copying being the effect of the cast. Be sure the source std::string holds + * UTF8 encoded text before you do that. * * @author Dick Hollenbeck */ @@ -73,53 +79,54 @@ public: * @param aResult is where to put the unicode character, and may be NULL if no interest. * @return int - the count of bytes consumed. */ - static int uni_forward( unsigned char* aSequence, unsigned* aResult = NULL ); + static int uni_forward( const unsigned char* aSequence, unsigned* aResult = NULL ); /** * class uni_iter - * is a non-mutable iterator that walks through code points in the UTF8 encoded - * string. The normal ++(), ++(int), ->(), and *() operators are all supported and - * they return an unsigned holding the unicode character appropriate for respective - * operation. + * is a non-muting iterator that walks through unicode code points in the UTF8 encoded + * string. The normal ++(), ++(int), ->(), and *() operators are all supported + * for read only access and they return an unsigned holding the unicode character + * appropriate for the respective operator. */ class uni_iter { friend class UTF8; - unsigned char* it; + const unsigned char* it; // private constructor. uni_iter( const char* start ) : - it( (unsigned char*) start ) + it( (const unsigned char*) start ) { // for the human: assert( sizeof(unsigned) >= 4 ); } + public: - /// pre-increment and return unicode at new position - unsigned operator++() + uni_iter( const uni_iter& o ) { - unsigned result; + it = o.it; + } - // advance over current, and toss the unicode result + /// pre-increment and return uni_iter at new position + const uni_iter& operator++() + { it += uni_forward( it ); - // get the next unicode result, but do not advance: - uni_forward( it, &result ); - return result; + return *this; } - /// post-increment and return unicode at initial position - unsigned operator++( int ) + /// post-increment and return uni_iter at initial position + uni_iter operator++( int ) { - unsigned result; + uni_iter ret = *this; - // grab the result and advance. - it += uni_forward( it, &result ); - return result; + it += uni_forward( it ); + return ret; } + /* /// return unicode at current position unsigned operator->() const { @@ -129,6 +136,7 @@ public: uni_forward( it, &result ); return result; } + */ /// return unicode at current position unsigned operator*() const @@ -142,6 +150,9 @@ public: bool operator==( const uni_iter& other ) const { return it == other.it; } bool operator!=( const uni_iter& other ) const { return it != other.it; } + + /// Since the ++ operators advance more than one byte, this is your best + /// loop termination test, < end(), not == end(). bool operator< ( const uni_iter& other ) const { return it < other.it; } bool operator<=( const uni_iter& other ) const { return it <= other.it; } bool operator> ( const uni_iter& other ) const { return it > other.it; } @@ -150,7 +161,7 @@ public: /** * Function ubegin - * returns a @a uni_iter initialized to the start of this UTF8 byte sequence. + * returns a @a uni_iter initialized to the start of "this" UTF8 byte sequence. */ uni_iter ubegin() const { @@ -159,7 +170,7 @@ public: /** * Function uend - * returns a @a uni_iter initialized to the end of this UTF8 byte sequence. + * returns a @a uni_iter initialized to the end of "this" UTF8 byte sequence. */ uni_iter uend() const { @@ -213,14 +224,26 @@ int main() for( UTF8::uni_iter it = u2.ubegin(); it < u2.uend(); ) { // test post-increment: - printf( " _%c_", it++ ); + printf( " _%c_", *it++ ); // after UTF8::uni_forward() is implemented, %c is no longer useable. - // printf( " _%02x_", it++ ); + // printf( " _%02x_", *it++ ); } printf( "\n" ); + UTF8::uni_iter it = u2.ubegin(); + + UTF8::uni_iter it2 = it++; + + printf( "post_inc:'%c' should be 'i'\n", *it2 ); + + it2 = ++it; + + printf( "pre_inc:'%c' should be 'p'\n", *it2 ); + + printf( "u[1]:'%c' should be 'n'\n", u2[1] ); + return 0; } @@ -253,30 +276,6 @@ UTF8& UTF8::operator=( const wxString& o ) } -static const unsigned char utf8_len[256] = { - // Map encoded prefix byte to sequence length. Zero means - // illegal prefix. See RFC 3629 for details - /* - 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 00-0F - 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, - 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, - 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, - 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, - 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, - 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, - 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 70-7F - */ - 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 80-8F - 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, - 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, - 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // B0-BF - 0, 0, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, // C0-C1 + C2-CF - 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, // D0-DF - 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, // E0-EF - 4, 4, 4, 4, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 // F0-F4 + F5-FF -}; - - #ifndef THROW_IO_ERROR #define THROW_IO_ERROR(x) // nothing #endif @@ -284,7 +283,7 @@ static const unsigned char utf8_len[256] = { // There is no wxWidgets function that does this, because wchar_t is 16 bits // on windows and wx wants to encode the output in UTF16 for such. -int UTF8::uni_forward( unsigned char* aSequence, unsigned* aResult ) +int UTF8::uni_forward( const unsigned char* aSequence, unsigned* aResult ) { unsigned ch = *aSequence; @@ -295,7 +294,30 @@ int UTF8::uni_forward( unsigned char* aSequence, unsigned* aResult ) return 1; } - unsigned char* s = aSequence; + const unsigned char* s = aSequence; + + static const unsigned char utf8_len[] = { + // Map encoded prefix byte to sequence length. Zero means + // illegal prefix. See RFC 3629 for details + /* + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 00-0F + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, + 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 70-7F + */ + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 80-8F + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // B0-BF + 0, 0, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, // C0-C1 + C2-CF + 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, // D0-DF + 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, // E0-EF + 4, 4, 4, 4, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 // F0-F4 + F5-FF + }; int len = utf8_len[ *s - 0x80 /* top half of table is missing */ ];