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Unification utf16/utf32 to utf8 conversion
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Signed-off-by: Vladislav Shchapov <vladislav@shchapov.ru>
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@phprus
phprus committed May 2, 2023
1 parent d76e4d6 commit 192ece7
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Showing 7 changed files with 88 additions and 142 deletions.
36 changes: 5 additions & 31 deletions include/fmt/chrono.h
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Expand Up @@ -377,37 +377,11 @@ auto write_encoded_tm_str(OutputIt out, string_view in, const std::locale& loc)
unit_t unit;
write_codecvt(unit, in, loc);
// In UTF-8 is used one to four one-byte code units.
auto&& buf = basic_memory_buffer<char, unit_t::max_size * 4>();
for (code_unit* p = unit.buf; p != unit.end; ++p) {
uint32_t c = static_cast<uint32_t>(*p);
if (sizeof(code_unit) == 2 && c >= 0xd800 && c <= 0xdfff) {
// surrogate pair
++p;
if (p == unit.end || (c & 0xfc00) != 0xd800 ||
(*p & 0xfc00) != 0xdc00) {
FMT_THROW(format_error("failed to format time"));
}
c = (c << 10) + static_cast<uint32_t>(*p) - 0x35fdc00;
}
if (c < 0x80) {
buf.push_back(static_cast<char>(c));
} else if (c < 0x800) {
buf.push_back(static_cast<char>(0xc0 | (c >> 6)));
buf.push_back(static_cast<char>(0x80 | (c & 0x3f)));
} else if ((c >= 0x800 && c <= 0xd7ff) || (c >= 0xe000 && c <= 0xffff)) {
buf.push_back(static_cast<char>(0xe0 | (c >> 12)));
buf.push_back(static_cast<char>(0x80 | ((c & 0xfff) >> 6)));
buf.push_back(static_cast<char>(0x80 | (c & 0x3f)));
} else if (c >= 0x10000 && c <= 0x10ffff) {
buf.push_back(static_cast<char>(0xf0 | (c >> 18)));
buf.push_back(static_cast<char>(0x80 | ((c & 0x3ffff) >> 12)));
buf.push_back(static_cast<char>(0x80 | ((c & 0xfff) >> 6)));
buf.push_back(static_cast<char>(0x80 | (c & 0x3f)));
} else {
FMT_THROW(format_error("failed to format time"));
}
}
return copy_str<char>(buf.data(), buf.data() + buf.size(), out);
unicode_to_utf8<code_unit, basic_memory_buffer<char, unit_t::max_size * 4>>
u;
if (!u.convert({unit.buf, to_unsigned(unit.end - unit.buf)}))
FMT_THROW(format_error("failed to format time"));
return copy_str<char>(u.c_str(), u.c_str() + u.size(), out);
}
return copy_str<char>(in.data(), in.data() + in.size(), out);
}
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62 changes: 62 additions & 0 deletions include/fmt/format.h
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Expand Up @@ -1416,6 +1416,68 @@ class utf8_to_utf16 {
auto str() const -> std::wstring { return {&buffer_[0], size()}; }
};

// A converter from UTF-16/UTF-32 (host endian) to UTF-8.
template <typename WChar, typename Buffer = memory_buffer>
class unicode_to_utf8 {
private:
Buffer buffer_;

public:
unicode_to_utf8() {}
explicit unicode_to_utf8(basic_string_view<WChar> s) {
static_assert(sizeof(WChar) == 2 || sizeof(WChar) == 4,
"Expect utf16 or utf32");

if (!convert(s))
FMT_THROW(std::runtime_error(sizeof(WChar) == 2 ? "invalid utf16"
: "invalid utf32"));
}
operator string_view() const { return string_view(&buffer_[0], size()); }
size_t size() const { return buffer_.size() - 1; }
const char* c_str() const { return &buffer_[0]; }
std::string str() const { return std::string(&buffer_[0], size()); }

// Performs conversion returning a bool instead of throwing exception on
// conversion error. This method may still throw in case of memory allocation
// error.
bool convert(basic_string_view<WChar> s) {
if (!convert(buffer_, s)) return false;
buffer_.push_back(0);
return true;
}
static bool convert(Buffer& buf, basic_string_view<WChar> s) {
for (auto p = s.begin(); p != s.end(); ++p) {
uint32_t c = static_cast<uint32_t>(*p);
if (sizeof(WChar) == 2 && c >= 0xd800 && c <= 0xdfff) {
// surrogate pair
++p;
if (p == s.end() || (c & 0xfc00) != 0xd800 || (*p & 0xfc00) != 0xdc00) {
return false;
}
c = (c << 10) + static_cast<uint32_t>(*p) - 0x35fdc00;
}
if (c < 0x80) {
buf.push_back(static_cast<char>(c));
} else if (c < 0x800) {
buf.push_back(static_cast<char>(0xc0 | (c >> 6)));
buf.push_back(static_cast<char>(0x80 | (c & 0x3f)));
} else if ((c >= 0x800 && c <= 0xd7ff) || (c >= 0xe000 && c <= 0xffff)) {
buf.push_back(static_cast<char>(0xe0 | (c >> 12)));
buf.push_back(static_cast<char>(0x80 | ((c & 0xfff) >> 6)));
buf.push_back(static_cast<char>(0x80 | (c & 0x3f)));
} else if (c >= 0x10000 && c <= 0x10ffff) {
buf.push_back(static_cast<char>(0xf0 | (c >> 18)));
buf.push_back(static_cast<char>(0x80 | ((c & 0x3ffff) >> 12)));
buf.push_back(static_cast<char>(0x80 | ((c & 0xfff) >> 6)));
buf.push_back(static_cast<char>(0x80 | (c & 0x3f)));
} else {
return false;
}
}
return true;
}
};

// Computes 128-bit result of multiplication of two 64-bit unsigned integers.
inline uint128_fallback umul128(uint64_t x, uint64_t y) noexcept {
#if FMT_USE_INT128
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20 changes: 0 additions & 20 deletions include/fmt/os.h
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Expand Up @@ -124,26 +124,6 @@ using wcstring_view = basic_cstring_view<wchar_t>;
FMT_API const std::error_category& system_category() noexcept;

FMT_BEGIN_DETAIL_NAMESPACE
// A converter from UTF-16 to UTF-8.
// It is only provided for Windows since other systems support UTF-8 natively.
class utf16_to_utf8 {
private:
memory_buffer buffer_;

public:
utf16_to_utf8() {}
FMT_API explicit utf16_to_utf8(basic_string_view<wchar_t> s);
operator string_view() const { return string_view(&buffer_[0], size()); }
size_t size() const { return buffer_.size() - 1; }
const char* c_str() const { return &buffer_[0]; }
std::string str() const { return std::string(&buffer_[0], size()); }

// Performs conversion returning a system error code instead of
// throwing exception on conversion error. This method may still throw
// in case of memory allocation error.
FMT_API int convert(basic_string_view<wchar_t> s);
};

FMT_API void format_windows_error(buffer<char>& out, int error_code,
const char* message) noexcept;
FMT_END_DETAIL_NAMESPACE
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16 changes: 3 additions & 13 deletions include/fmt/std.h
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Expand Up @@ -60,19 +60,9 @@ inline void write_escaped_path<char>(memory_buffer& quoted,
const std::filesystem::path& p) {
auto buf = basic_memory_buffer<wchar_t>();
write_escaped_string<wchar_t>(std::back_inserter(buf), p.native());
for (unsigned c : buf) {
// Convert UTF-16 to UTF-8.
if (c < 0x80) {
quoted.push_back(static_cast<unsigned char>(c));
} else if (c < 0x800) {
quoted.push_back(0b1100'0000 | ((c >> 6) & 0b01'1111));
quoted.push_back(0b1000'0000 | (c & 0b11'1111));
} else {
quoted.push_back(0b1110'0000 | ((c >> 12) & 0b01'1111));
quoted.push_back(0b1000'0000 | ((c >> 6) & 0b11'1111));
quoted.push_back(0b1000'0000 | (c & 0b11'1111));
}
}
// Convert UTF-16 to UTF-8.
if (!unicode_to_utf8<wchar_t>::convert(quoted, {buf.data(), buf.size()}))
FMT_THROW(std::runtime_error("invalid utf16"));
}
# endif
template <>
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41 changes: 7 additions & 34 deletions src/os.cc
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Expand Up @@ -72,34 +72,6 @@ inline std::size_t convert_rwcount(std::size_t count) { return count; }
FMT_BEGIN_NAMESPACE

#ifdef _WIN32
detail::utf16_to_utf8::utf16_to_utf8(basic_string_view<wchar_t> s) {
if (int error_code = convert(s)) {
FMT_THROW(windows_error(error_code,
"cannot convert string from UTF-16 to UTF-8"));
}
}

int detail::utf16_to_utf8::convert(basic_string_view<wchar_t> s) {
if (s.size() > INT_MAX) return ERROR_INVALID_PARAMETER;
int s_size = static_cast<int>(s.size());
if (s_size == 0) {
// WideCharToMultiByte does not support zero length, handle separately.
buffer_.resize(1);
buffer_[0] = 0;
return 0;
}

int length = WideCharToMultiByte(CP_UTF8, 0, s.data(), s_size, nullptr, 0,
nullptr, nullptr);
if (length == 0) return GetLastError();
buffer_.resize(length + 1);
length = WideCharToMultiByte(CP_UTF8, 0, s.data(), s_size, &buffer_[0],
length, nullptr, nullptr);
if (length == 0) return GetLastError();
buffer_[length] = 0;
return 0;
}

namespace detail {

class system_message {
Expand Down Expand Up @@ -140,8 +112,8 @@ class utf8_system_category final : public std::error_category {
std::string message(int error_code) const override {
system_message msg(error_code);
if (msg) {
utf16_to_utf8 utf8_message;
if (utf8_message.convert(msg) == ERROR_SUCCESS) {
unicode_to_utf8<wchar_t> utf8_message;
if (utf8_message.convert(msg)) {
return utf8_message.str();
}
}
Expand All @@ -167,8 +139,8 @@ void detail::format_windows_error(detail::buffer<char>& out, int error_code,
FMT_TRY {
system_message msg(error_code);
if (msg) {
auto utf8_message = utf16_to_utf8();
if (utf8_message.convert(msg) == ERROR_SUCCESS) {
unicode_to_utf8<wchar_t> utf8_message;
if (utf8_message.convert(msg)) {
fmt::format_to(buffer_appender<char>(out), "{}: {}", message,
string_view(utf8_message));
return;
Expand Down Expand Up @@ -365,8 +337,9 @@ file file::open_windows_file(wcstring_view path, int oflag) {
int fd = -1;
auto err = _wsopen_s(&fd, path.c_str(), oflag, _SH_DENYNO, default_open_mode);
if (fd == -1) {
FMT_THROW(system_error(err, FMT_STRING("cannot open file {}"),
detail::utf16_to_utf8(path.c_str()).c_str()));
FMT_THROW(
system_error(err, FMT_STRING("cannot open file {}"),
detail::unicode_to_utf8<wchar_t>(path.c_str()).c_str()));
}
return file(fd);
}
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7 changes: 7 additions & 0 deletions test/format-impl-test.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -559,3 +559,10 @@ TEST(format_impl_test, utf8_decode_bogus_byte_sequences) {
EXPECT_NE(e, 0); // "bogus [c0 0a] 0x%02x U+%04lx", e, (unsigned long)c
EXPECT_EQ(len, 2); // "bogus [c0 0a] recovery %d", len);
}

TEST(format_impl_test, unicode_to_utf8) {
auto s = std::string("ёжик");
fmt::detail::unicode_to_utf8<wchar_t> u(L"\x0451\x0436\x0438\x043A");
EXPECT_EQ(s, u.str());
EXPECT_EQ(s.size(), u.size());
}
48 changes: 4 additions & 44 deletions test/os-test.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -22,56 +22,15 @@ using wstring_view = fmt::basic_string_view<wchar_t>;

# include <windows.h>

TEST(util_test, utf16_to_utf8) {
auto s = std::string("ёжик");
fmt::detail::utf16_to_utf8 u(L"\x0451\x0436\x0438\x043A");
EXPECT_EQ(s, u.str());
EXPECT_EQ(s.size(), u.size());
}

TEST(util_test, utf16_to_utf8_empty_string) {
std::string s = "";
fmt::detail::utf16_to_utf8 u(L"");
EXPECT_EQ(s, u.str());
EXPECT_EQ(s.size(), u.size());
}

template <typename Converter, typename Char>
void check_utf_conversion_error(const char* message,
fmt::basic_string_view<Char> str =
fmt::basic_string_view<Char>(nullptr, 1)) {
fmt::memory_buffer out;
fmt::detail::format_windows_error(out, ERROR_INVALID_PARAMETER, message);
auto error = std::system_error(std::error_code());
try {
(Converter)(str);
} catch (const std::system_error& e) {
error = e;
}
EXPECT_EQ(ERROR_INVALID_PARAMETER, error.code().value());
EXPECT_THAT(error.what(), HasSubstr(fmt::to_string(out)));
}

TEST(util_test, utf16_to_utf8_error) {
check_utf_conversion_error<fmt::detail::utf16_to_utf8, wchar_t>(
"cannot convert string from UTF-16 to UTF-8");
}

TEST(util_test, utf16_to_utf8_convert) {
fmt::detail::utf16_to_utf8 u;
EXPECT_EQ(ERROR_INVALID_PARAMETER, u.convert(wstring_view(nullptr, 1)));
EXPECT_EQ(ERROR_INVALID_PARAMETER,
u.convert(wstring_view(L"foo", INT_MAX + 1u)));
}

TEST(os_test, format_windows_error) {
LPWSTR message = nullptr;
auto result = FormatMessageW(
FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_IGNORE_INSERTS,
nullptr, ERROR_FILE_EXISTS, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
reinterpret_cast<LPWSTR>(&message), 0, nullptr);
fmt::detail::utf16_to_utf8 utf8_message(wstring_view(message, result - 2));
fmt::detail::unicode_to_utf8<wchar_t> utf8_message(
wstring_view(message, result - 2));
LocalFree(message);
fmt::memory_buffer actual_message;
fmt::detail::format_windows_error(actual_message, ERROR_FILE_EXISTS, "test");
Expand All @@ -96,7 +55,8 @@ TEST(os_test, format_long_windows_error) {
LocalFree(message);
return;
}
fmt::detail::utf16_to_utf8 utf8_message(wstring_view(message, result - 2));
fmt::detail::unicode_to_utf8<wchar_t> utf8_message(
wstring_view(message, result - 2));
LocalFree(message);
fmt::memory_buffer actual_message;
fmt::detail::format_windows_error(actual_message, provisioning_not_allowed,
Expand Down

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