| // Copyright 2009 The Chromium Authors |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "base/strings/utf_string_conversion_utils.h" |
| |
| #include "base/third_party/icu/icu_utf.h" |
| #include "build/build_config.h" |
| |
| namespace gurl_base { |
| |
| // CountUnicodeCharacters ------------------------------------------------------ |
| |
| absl::optional<size_t> CountUnicodeCharacters(std::string_view text, |
| size_t limit) { |
| base_icu::UChar32 unused = 0; |
| size_t count = 0; |
| for (size_t index = 0; count < limit && index < text.size(); |
| ++count, ++index) { |
| if (!ReadUnicodeCharacter(text.data(), text.size(), &index, &unused)) { |
| return absl::nullopt; |
| } |
| } |
| return count; |
| } |
| |
| // ReadUnicodeCharacter -------------------------------------------------------- |
| |
| bool ReadUnicodeCharacter(const char* src, |
| size_t src_len, |
| size_t* char_index, |
| base_icu::UChar32* code_point_out) { |
| base_icu::UChar32 code_point; |
| CBU8_NEXT(reinterpret_cast<const uint8_t*>(src), *char_index, src_len, |
| code_point); |
| *code_point_out = code_point; |
| |
| // The ICU macro above moves to the next char, we want to point to the last |
| // char consumed. |
| (*char_index)--; |
| |
| // Validate the decoded value. |
| return IsValidCodepoint(code_point); |
| } |
| |
| bool ReadUnicodeCharacter(const char16_t* src, |
| size_t src_len, |
| size_t* char_index, |
| base_icu::UChar32* code_point) { |
| if (CBU16_IS_SURROGATE(src[*char_index])) { |
| if (!CBU16_IS_SURROGATE_LEAD(src[*char_index]) || !src_len || |
| *char_index >= src_len - 1 || !CBU16_IS_TRAIL(src[*char_index + 1])) { |
| // Invalid surrogate pair. |
| return false; |
| } |
| |
| // Valid surrogate pair. |
| *code_point = CBU16_GET_SUPPLEMENTARY(src[*char_index], |
| src[*char_index + 1]); |
| (*char_index)++; |
| } else { |
| // Not a surrogate, just one 16-bit word. |
| *code_point = src[*char_index]; |
| } |
| |
| return IsValidCodepoint(*code_point); |
| } |
| |
| #if defined(WCHAR_T_IS_32_BIT) |
| bool ReadUnicodeCharacter(const wchar_t* src, |
| size_t src_len, |
| size_t* char_index, |
| base_icu::UChar32* code_point) { |
| // Conversion is easy since the source is 32-bit. |
| *code_point = static_cast<base_icu::UChar32>(src[*char_index]); |
| |
| // Validate the value. |
| return IsValidCodepoint(*code_point); |
| } |
| #endif // defined(WCHAR_T_IS_32_BIT) |
| |
| // WriteUnicodeCharacter ------------------------------------------------------- |
| |
| size_t WriteUnicodeCharacter(base_icu::UChar32 code_point, |
| std::string* output) { |
| if (code_point >= 0 && code_point <= 0x7f) { |
| // Fast path the common case of one byte. |
| output->push_back(static_cast<char>(code_point)); |
| return 1; |
| } |
| |
| // CBU8_APPEND_UNSAFE can append up to 4 bytes. |
| size_t char_offset = output->length(); |
| size_t original_char_offset = char_offset; |
| output->resize(char_offset + CBU8_MAX_LENGTH); |
| |
| CBU8_APPEND_UNSAFE(reinterpret_cast<uint8_t*>(output->data()), char_offset, |
| code_point); |
| |
| // CBU8_APPEND_UNSAFE will advance our pointer past the inserted character, so |
| // it will represent the new length of the string. |
| output->resize(char_offset); |
| return char_offset - original_char_offset; |
| } |
| |
| size_t WriteUnicodeCharacter(base_icu::UChar32 code_point, |
| std::u16string* output) { |
| if (CBU16_LENGTH(code_point) == 1) { |
| // The code point is in the Basic Multilingual Plane (BMP). |
| output->push_back(static_cast<char16_t>(code_point)); |
| return 1; |
| } |
| // Non-BMP characters use a double-character encoding. |
| size_t char_offset = output->length(); |
| output->resize(char_offset + CBU16_MAX_LENGTH); |
| CBU16_APPEND_UNSAFE(&(*output)[0], char_offset, code_point); |
| return CBU16_MAX_LENGTH; |
| } |
| |
| // Generalized Unicode converter ----------------------------------------------- |
| |
| template<typename CHAR> |
| void PrepareForUTF8Output(const CHAR* src, |
| size_t src_len, |
| std::string* output) { |
| output->clear(); |
| if (src_len == 0) |
| return; |
| if (src[0] < 0x80) { |
| // Assume that the entire input will be ASCII. |
| output->reserve(src_len); |
| } else { |
| // Assume that the entire input is non-ASCII and will have 3 bytes per char. |
| output->reserve(src_len * 3); |
| } |
| } |
| |
| // Instantiate versions we know callers will need. |
| #if !BUILDFLAG(IS_WIN) |
| // wchar_t and char16_t are the same thing on Windows. |
| template void PrepareForUTF8Output(const wchar_t*, size_t, std::string*); |
| #endif |
| template void PrepareForUTF8Output(const char16_t*, size_t, std::string*); |
| |
| template<typename STRING> |
| void PrepareForUTF16Or32Output(const char* src, |
| size_t src_len, |
| STRING* output) { |
| output->clear(); |
| if (src_len == 0) |
| return; |
| if (static_cast<unsigned char>(src[0]) < 0x80) { |
| // Assume the input is all ASCII, which means 1:1 correspondence. |
| output->reserve(src_len); |
| } else { |
| // Otherwise assume that the UTF-8 sequences will have 2 bytes for each |
| // character. |
| output->reserve(src_len / 2); |
| } |
| } |
| |
| // Instantiate versions we know callers will need. |
| #if !BUILDFLAG(IS_WIN) |
| // std::wstring and std::u16string are the same thing on Windows. |
| template void PrepareForUTF16Or32Output(const char*, size_t, std::wstring*); |
| #endif |
| template void PrepareForUTF16Or32Output(const char*, size_t, std::u16string*); |
| |
| } // namespace base |