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Diffstat (limited to 'shared/string_utf8.h')
| -rw-r--r-- | shared/string_utf8.h | 333 |
1 files changed, 333 insertions, 0 deletions
diff --git a/shared/string_utf8.h b/shared/string_utf8.h new file mode 100644 index 00000000..f6f12d8f --- /dev/null +++ b/shared/string_utf8.h @@ -0,0 +1,333 @@ +// ************************************************************************** +// * This file is part of the zenXML project. It is distributed under the * +// * Boost Software License, Version 1.0. See accompanying file * +// * LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt. * +// * Copyright (C) 2011 ZenJu (zhnmju123 AT gmx.de) * +// ************************************************************************** + +#ifndef STRING_UTF8_HEADER_01832479146991573473545 +#define STRING_UTF8_HEADER_01832479146991573473545 + +#include <iterator> +#include "loki/TypeManip.h" +#include "string_tools.h" +#include "assert_static.h" + +namespace zen +{ +//Example: std::string tmp = toUtf8<std::string>(L"abc"); +template <class CharString, class WideString> +CharString wideToUtf8(const WideString& str); + +//Example: std::wstring tmp = utf8To<std::wstring>("abc"); +template <class WideString, class CharString> +WideString utf8ToWide(const CharString& str); + +const char BYTE_ORDER_MARK_UTF8[] = "\xEF\xBB\xBF"; + +//convert any(!) "string-like" object into a UTF8 encoded std::string +template <class String> std::string toStdString(const String& str); +//convert a UTF8 encoded std::string to any(!) string-class +template <class String> String stdStringTo(const std::string& str); + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +//----------------------- implementation ---------------------------------- +namespace implementation +{ +typedef unsigned int CodePoint; + +const CodePoint CODE_POINT_MAX = 0x10ffff; + +const CodePoint HIGH_SURROGATE = 0xd800; +const CodePoint HIGH_SURROGATE_MAX = 0xdbff; + +const CodePoint LOW_SURROGATE = 0xdc00; +const CodePoint LOW_SURROGATE_MAX = 0xdfff; + + +template <class OutputIterator> inline +OutputIterator codePointToUtf16(CodePoint cp, OutputIterator result) //http://en.wikipedia.org/wiki/UTF-16 +{ + typedef unsigned short Char16; //this isn't necessarily 16 bit, but all we need is an unsigned type + + assert(cp < HIGH_SURROGATE || LOW_SURROGATE_MAX < cp); //code points [0xd800, 0xdfff] are not allowed for UTF-16 + assert(cp <= CODE_POINT_MAX); + + if (cp < 0x10000) + *result++ = static_cast<Char16>(cp); + else + { + cp -= 0x10000; + *result++ = static_cast<Char16>((cp >> 10) + HIGH_SURROGATE); + *result++ = static_cast<Char16>((cp & 0x3ff) + LOW_SURROGATE); + } + return result; +} + + +template <class CharIterator, class Function> inline +Function utf16ToCodePoint(CharIterator first, CharIterator last, Function f) //f is a unary function taking a CodePoint as single parameter +{ + assert_static(sizeof(typename std::iterator_traits<CharIterator>::value_type) == 2); + typedef unsigned short Char16; //this isn't necessarily 16 bit, but all we need is an unsigned type + + for ( ; first != last; ++first) + { + CodePoint cp = static_cast<Char16>(*first); + if (HIGH_SURROGATE <= cp && cp <= HIGH_SURROGATE_MAX) + { + if (++first == last) + { + assert(false); //low surrogate expected + break; + } + assert(LOW_SURROGATE <= static_cast<Char16>(*first) && static_cast<Char16>(*first) <= LOW_SURROGATE_MAX); //low surrogate expected + cp = ((cp - HIGH_SURROGATE) << 10) + static_cast<Char16>(*first) - LOW_SURROGATE + 0x10000; + } + else + assert(cp < LOW_SURROGATE || LOW_SURROGATE_MAX < cp); //NO low surrogate expected + + f(cp); + } + return f; +} + + +template <class OutputIterator> inline +OutputIterator codePointToUtf8(CodePoint cp, OutputIterator result) //http://en.wikipedia.org/wiki/UTF-8 +{ + typedef unsigned char Char8; + + assert(cp <= CODE_POINT_MAX); + + if (cp < 0x80) + *result++ = static_cast<Char8>(cp); + else if (cp < 0x800) + { + *result++ = static_cast<Char8>((cp >> 6 )| 0xc0); + *result++ = static_cast<Char8>((cp & 0x3f )| 0x80); + } + else if (cp < 0x10000) + { + *result++ = static_cast<Char8>((cp >> 12 )| 0xe0); + *result++ = static_cast<Char8>(((cp >> 6) & 0x3f )| 0x80); + *result++ = static_cast<Char8>((cp & 0x3f )| 0x80); + } + else + { + *result++ = static_cast<Char8>((cp >> 18 )| 0xf0); + *result++ = static_cast<Char8>(((cp >> 12) & 0x3f )| 0x80); + *result++ = static_cast<Char8>(((cp >> 6) & 0x3f )| 0x80); + *result++ = static_cast<Char8>((cp & 0x3f )| 0x80); + } + return result; +} + + +inline +size_t getUtf8Len(unsigned char ch) +{ + if (ch < 0x80) + return 1; + if (ch >> 5 == 0x6) + return 2; + if (ch >> 4 == 0xe) + return 3; + if (ch >> 3 == 0x1e) + return 4; + + assert(false); //no valid begin of UTF8 encoding + return 1; +} + + +template <class CharIterator, class Function> inline +Function utf8ToCodePoint(CharIterator first, CharIterator last, Function f) //f is a unary function taking a CodePoint as single parameter +{ + assert_static(sizeof(typename std::iterator_traits<CharIterator>::value_type) == 1); + typedef unsigned char Char8; + + for ( ; first != last; ++first) + { + auto getChar = [&](Char8& ch ) -> bool + { + if (++first == last) + { + assert(false); //low surrogate expected + return false; + } + ch = static_cast<Char8>(*first); + assert(ch >> 6 == 0x2); + return true; + }; + + CodePoint cp = static_cast<Char8>(*first); + switch (getUtf8Len(cp)) + { + case 1: + break; + case 2: + { + cp = (cp & 0x1f) << 6; + Char8 ch; + if (!getChar(ch)) continue; + cp += ch & 0x3f; + } + break; + case 3: + { + cp = (cp & 0xf) << 12; + Char8 ch; + if (!getChar(ch)) continue; + cp += (ch & 0x3f) << 6; + if (!getChar(ch)) continue; + cp += ch & 0x3f; + + } + break; + case 4: + { + cp = (cp & 0x7) << 18; + Char8 ch; + if (!getChar(ch)) continue; + cp += (ch & 0x3f) << 12; + if (!getChar(ch)) continue; + cp += (ch & 0x3f) << 6; + if (!getChar(ch)) continue; + cp += ch & 0x3f; + } + break; + default: + assert(false); + } + f(cp); + } + return f; +} + + +template <class String> +class AppendStringIterator: public std::iterator<std::output_iterator_tag, void, void, void, void> +{ +public: + explicit AppendStringIterator (String& x) : str(x) {} + AppendStringIterator& operator= (typename String::value_type value) { str += value; return *this; } + AppendStringIterator& operator* () { return *this; } + AppendStringIterator& operator++ () { return *this; } + AppendStringIterator operator++ (int) { return *this; } +private: + String& str; +}; + + +template <class WideString, class CharString> inline +WideString utf8ToWide(const CharString& str, Loki::Int2Type<2>) //windows: convert utf8 to utf16 wchar_t +{ + WideString output; + utf8ToCodePoint(strBegin(str), strBegin(str) + strLength(str), + [&](CodePoint cp) { codePointToUtf16(cp, AppendStringIterator<WideString>(output)); }); + return output; +} + + +template <class WideString, class CharString> inline +WideString utf8ToWide(const CharString& str, Loki::Int2Type<4>) //other OS: convert utf8 to utf32 wchar_t +{ + WideString output; + utf8ToCodePoint(strBegin(str), strBegin(str) + strLength(str), + [&](CodePoint cp) { output += cp; }); + return output; +} + + +template <class CharString, class WideString> inline +CharString wideToUtf8(const WideString& str, Loki::Int2Type<2>) //windows: convert utf16-wchar_t to utf8 +{ + CharString output; + utf16ToCodePoint(strBegin(str), strBegin(str) + strLength(str), + [&](CodePoint cp) { codePointToUtf8(cp, AppendStringIterator<CharString>(output)); }); + return output; +} + + +template <class CharString, class WideString> inline +CharString wideToUtf8(const WideString& str, Loki::Int2Type<4>) //other OS: convert utf32-wchar_t to utf8 +{ + CharString output; + std::for_each(strBegin(str), strBegin(str) + strLength(str), + [&](CodePoint cp) { codePointToUtf8(cp, AppendStringIterator<CharString>(output)); }); + return output; +} +} + + +template <class WideString, class CharString> inline +WideString utf8ToWide(const CharString& str) +{ + assert_static((Loki::IsSameType<typename StringTraits<CharString>::CharType, char >::value)); + assert_static((Loki::IsSameType<typename StringTraits<WideString>::CharType, wchar_t>::value)); + + return implementation::utf8ToWide<WideString>(str, Loki::Int2Type<sizeof(wchar_t)>()); +} + + +template <class CharString, class WideString> inline +CharString wideToUtf8(const WideString& str) +{ + assert_static((Loki::IsSameType<typename StringTraits<CharString>::CharType, char >::value)); + assert_static((Loki::IsSameType<typename StringTraits<WideString>::CharType, wchar_t>::value)); + + return implementation::wideToUtf8<CharString>(str, Loki::Int2Type<sizeof(wchar_t)>()); +} + + +//------------------------------------------------------------------------------------------- +template <class String> inline +std::string toStdString(const String& str, wchar_t) { return wideToUtf8<std::string>(str); } //convert wide character string to UTF8 + +template <class String> inline +std::string toStdString(const String& str, char) { return cvrtString<std::string>(str); } //directly process string without UTF8 conversion + +template <class String> inline +std::string toStdString(const String& str) { return toStdString(str, typename StringTraits<String>::CharType()); } +//------------------------------------------------------------------------------------------- + +template <class String> inline +String stdStringTo(const std::string& str, wchar_t) { return utf8ToWide<String>(str); } //convert UTF8 to wide character string + +template <class String> inline +String stdStringTo(const std::string& str, char) { return cvrtString<String>(str); } //directly process string without UTF8 conversion + +template <class String> inline +String stdStringTo(const std::string& str) { return stdStringTo<String>(str, typename StringTraits<String>::CharType()); } +} + +#endif //STRING_UTF8_HEADER_01832479146991573473545 |