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refs #18, some refactoring on unicode handling and a fix for a VS2019…
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… warning.
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@gulrak
gulrak committed May 18, 2019
1 parent 61182d0 commit 9d5bc60
Showing 1 changed file with 71 additions and 43 deletions.
114 changes: 71 additions & 43 deletions include/ghc/filesystem.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1179,59 +1179,58 @@ GHC_INLINE void appendUTF8(std::string& str, uint32_t unicode)
str.push_back(static_cast<char>(((unicode & 0xfff) >> 6) + 128));
str.push_back(static_cast<char>((unicode & 0x3f) + 128));
}
else {
else if (unicode >= 0x10000 && unicode <= 0x10ffff) {
str.push_back(static_cast<char>((unicode >> 18) + 240));
str.push_back(static_cast<char>(((unicode & 0x3ffff) >> 12) + 128));
str.push_back(static_cast<char>(((unicode & 0xfff) >> 6) + 128));
str.push_back(static_cast<char>((unicode & 0x3f) + 128));
}
else {
str.push_back(0xfffd);
}
}

// Thanks to Bjoern Hoehrmann (https://bjoern.hoehrmann.de/utf-8/decoder/dfa/)
// and Taylor R Campbell for the ideas to this DFA approach of UTF-8 decoding;
// Generating debugging and shrinking my own DFA from scratch was a day of fun!
GHC_INLINE unsigned consumeUtf8Fragment(const unsigned state, const uint8_t fragment, uint32_t& codepoint)
{
static const uint32_t utf8_state_info[] = {
0x11111111u, 0x11111111u, 0x77777777u, 0x77777777u, 0x88888888u, 0x88888888u, 0x88888888u, 0x88888888u, 0x22222299u, 0x22222222u, 0x22222222u, 0x22222222u, 0x3333333au, 0x33433333u,
0x9995666bu, 0x99999999u, 0x88888880u, 0x22818108u, 0x88888881u, 0x88888882u, 0x88888884u, 0x88888887u, 0x88888886u, 0x82218108u, 0x82281108u, 0x88888888u, 0x88888883u, 0x88888885u,
};
static const uint32_t utf8_state_info[] = {0x11111111u, 0x11111111u, 0x77777777u, 0x77777777u, 0x88888888u, 0x88888888u, 0x88888888u, 0x88888888u, 0x22222299u, 0x22222222u, 0x22222222u, 0x22222222u, 0x3333333au, 0x33433333u, 0x9995666bu, 0x99999999u,
0x88888880u, 0x22818108u, 0x88888881u, 0x88888882u, 0x88888884u, 0x88888887u, 0x88888886u, 0x82218108u, 0x82281108u, 0x88888888u, 0x88888883u, 0x88888885u, 0u, 0u, 0u, 0u};
uint8_t category = fragment < 128 ? 0 : (utf8_state_info[(fragment >> 3) & 0xf] >> ((fragment & 7) << 2)) & 0xf;
codepoint = (state ? (codepoint << 6) | (fragment & 0x3f) : (0xff >> category) & fragment);
return state == S_RJCT ? static_cast<unsigned>(S_RJCT) : static_cast<unsigned>((utf8_state_info[category + 16] >> (state << 2)) & 0xf);
}

} // namespace detail

#endif

namespace detail {

template <class StringType, typename std::enable_if<(sizeof(typename StringType::value_type) == 1)>::type* = nullptr>
inline StringType fromUtf8(const std::string& utf8String, const typename StringType::allocator_type& alloc = typename StringType::allocator_type())
{
return StringType(utf8String.begin(), utf8String.end());
}

template <class StringType>
template <class StringType, typename std::enable_if<(sizeof(typename StringType::value_type) == 2)>::type* = nullptr>
inline StringType fromUtf8(const std::string& utf8String, const typename StringType::allocator_type& alloc = typename StringType::allocator_type())
{
if (sizeof(typename StringType::value_type) == 1) {
return StringType(utf8String.begin(), utf8String.end());
}
StringType result(alloc);
result.reserve(utf8String.length());
std::string::const_iterator iter = utf8String.begin();
unsigned utf8_state = S_STRT;
std::uint32_t codepoint = 0;
while (iter < utf8String.end()) {
if ((utf8_state = consumeUtf8Fragment(utf8_state, (uint8_t)*iter++, codepoint)) == S_STRT) {
if (sizeof(typename StringType::value_type) == 4) {
result += codepoint;
if (codepoint <= 0xffff) {
result += (typename StringType::value_type)codepoint;
}
else {
if (codepoint <= 0xffff) {
result += (typename StringType::value_type)codepoint;
}
else {
codepoint -= 0x10000;
result += (typename StringType::value_type)((codepoint >> 10) + 0xd800);
result += (typename StringType::value_type)((codepoint & 0x3ff) + 0xdc00);
}
codepoint -= 0x10000;
result += (typename StringType::value_type)((codepoint >> 10) + 0xd800);
result += (typename StringType::value_type)((codepoint & 0x3ff) + 0xdc00);
}
codepoint = 0;
}
Expand All @@ -1247,40 +1246,69 @@ inline StringType fromUtf8(const std::string& utf8String, const typename StringT
return result;
}

template <typename charT, typename traits, typename Alloc>
inline std::string toUtf8(const std::basic_string<charT, traits, Alloc>& unicodeString)
template <class StringType, typename std::enable_if<(sizeof(typename StringType::value_type) == 4)>::type* = nullptr>
inline StringType fromUtf8(const std::string& utf8String, const typename StringType::allocator_type& alloc = typename StringType::allocator_type())
{
using StringType = std::basic_string<charT, traits, Alloc>;
if (sizeof(typename StringType::value_type) == 1) {
return std::string(unicodeString.begin(), unicodeString.end());
StringType result(alloc);
result.reserve(utf8String.length());
std::string::const_iterator iter = utf8String.begin();
unsigned utf8_state = S_STRT;
std::uint32_t codepoint = 0;
while (iter < utf8String.end()) {
if ((utf8_state = consumeUtf8Fragment(utf8_state, (uint8_t)*iter++, codepoint)) == S_STRT) {
result += codepoint;
codepoint = 0;
}
else if (utf8_state == S_RJCT) {
result += (typename StringType::value_type)0xfffd;
utf8_state = S_STRT;
codepoint = 0;
}
}
if (utf8_state) {
result += (typename StringType::value_type)0xfffd;
}
return result;
}

template <typename charT, typename traits, typename Alloc, typename std::enable_if<(sizeof(charT) == 1)>::type* = nullptr>
inline std::string toUtf8(const std::basic_string<charT, traits, Alloc>& unicodeString)
{
return std::string(unicodeString.begin(), unicodeString.end());
}

template <typename charT, typename traits, typename Alloc, typename std::enable_if<(sizeof(charT) == 2)>::type* = nullptr>
inline std::string toUtf8(const std::basic_string<charT, traits, Alloc>& unicodeString)
{
std::string result;
result.reserve(unicodeString.length());
if (sizeof(typename StringType::value_type) == 2) {
for (typename StringType::const_iterator iter = unicodeString.begin(); iter != unicodeString.end(); ++iter) {
char32_t c = *iter;
if (is_surrogate(c)) {
++iter;
if (iter != unicodeString.end() && is_high_surrogate(c) && is_low_surrogate(*iter)) {
appendUTF8(result, (char32_t(c) << 10) + *iter - 0x35fdc00);
}
else {
appendUTF8(result, 0xfffd);
}
for (auto iter = unicodeString.begin(); iter != unicodeString.end(); ++iter) {
char32_t c = *iter;
if (is_surrogate(c)) {
++iter;
if (iter != unicodeString.end() && is_high_surrogate(c) && is_low_surrogate(*iter)) {
appendUTF8(result, (char32_t(c) << 10) + *iter - 0x35fdc00);
}
else {
appendUTF8(result, c);
appendUTF8(result, 0xfffd);
}
}
}
else {
for (char32_t c : unicodeString) {
else {
appendUTF8(result, c);
}
}
return result;
}

template <typename charT, typename traits, typename Alloc, typename std::enable_if<(sizeof(charT) == 4)>::type* = nullptr>
inline std::string toUtf8(const std::basic_string<charT, traits, Alloc>& unicodeString)
{
std::string result;
for (auto c : unicodeString) {
appendUTF8(result, c);
}
return result;
}

template <typename SourceType>
inline std::string toUtf8(const SourceType* unicodeString)
{
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