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std::wstring utf8_to_utf16(const std::string& utf8) | |
{ | |
std::vector<unsigned long> unicode; | |
size_t i = 0; | |
while (i < utf8.size()) | |
{ | |
unsigned long uni; | |
size_t todo; | |
bool error = false; | |
unsigned char ch = utf8[i++]; | |
if (ch <= 0x7F) | |
{ | |
uni = ch; | |
todo = 0; | |
} | |
else if (ch <= 0xBF) | |
{ | |
throw std::logic_error("not a UTF-8 string"); | |
} | |
else if (ch <= 0xDF) | |
{ | |
uni = ch&0x1F; | |
todo = 1; | |
} | |
else if (ch <= 0xEF) | |
{ | |
uni = ch&0x0F; | |
todo = 2; | |
} | |
else if (ch <= 0xF7) | |
{ | |
uni = ch&0x07; | |
todo = 3; | |
} | |
else | |
{ | |
throw std::logic_error("not a UTF-8 string"); | |
} | |
for (size_t j = 0; j < todo; ++j) | |
{ | |
if (i == utf8.size()) | |
throw std::logic_error("not a UTF-8 string"); | |
unsigned char ch = utf8[i++]; | |
if (ch < 0x80 || ch > 0xBF) | |
throw std::logic_error("not a UTF-8 string"); | |
uni <<= 6; | |
uni += ch & 0x3F; | |
} | |
if (uni >= 0xD800 && uni <= 0xDFFF) | |
throw std::logic_error("not a UTF-8 string"); | |
if (uni > 0x10FFFF) | |
throw std::logic_error("not a UTF-8 string"); | |
unicode.push_back(uni); | |
} | |
std::wstring utf16; | |
for (size_t i = 0; i < unicode.size(); ++i) | |
{ | |
unsigned long uni = unicode[i]; | |
if (uni <= 0xFFFF) | |
{ | |
utf16 += (wchar_t)uni; | |
} | |
else | |
{ | |
uni -= 0x10000; | |
utf16 += (wchar_t)((uni >> 10) + 0xD800); | |
utf16 += (wchar_t)((uni & 0x3FF) + 0xDC00); | |
} | |
} | |
return utf16; | |
} |
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