343 lines
9.9 KiB
C++
343 lines
9.9 KiB
C++
// Copyright (c) 2018 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "base/strings/utf_string_conversions.h"
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#include <limits.h>
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#include <stdint.h>
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#include <type_traits>
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#include "base/strings/string_piece.h"
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#include "base/strings/string_util.h"
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#include "base/strings/utf_string_conversion_utils.h"
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#include "base/third_party/icu/icu_utf.h"
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#include "build/build_config.h"
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namespace base {
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namespace {
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constexpr int32_t kErrorCodePoint = 0xFFFD;
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// Size coefficient ----------------------------------------------------------
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// The maximum number of codeunits in the destination encoding corresponding to
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// one codeunit in the source encoding.
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template <typename SrcChar, typename DestChar>
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struct SizeCoefficient {
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static_assert(sizeof(SrcChar) < sizeof(DestChar),
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"Default case: from a smaller encoding to the bigger one");
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// ASCII symbols are encoded by one codeunit in all encodings.
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static constexpr int value = 1;
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};
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template <>
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struct SizeCoefficient<char16, char> {
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// One UTF-16 codeunit corresponds to at most 3 codeunits in UTF-8.
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static constexpr int value = 3;
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};
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#if defined(WCHAR_T_IS_UTF32)
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template <>
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struct SizeCoefficient<wchar_t, char> {
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// UTF-8 uses at most 4 codeunits per character.
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static constexpr int value = 4;
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};
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template <>
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struct SizeCoefficient<wchar_t, char16> {
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// UTF-16 uses at most 2 codeunits per character.
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static constexpr int value = 2;
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};
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#endif // defined(WCHAR_T_IS_UTF32)
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template <typename SrcChar, typename DestChar>
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constexpr int size_coefficient_v =
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SizeCoefficient<std::decay_t<SrcChar>, std::decay_t<DestChar>>::value;
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// UnicodeAppendUnsafe --------------------------------------------------------
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// Function overloads that write code_point to the output string. Output string
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// has to have enough space for the codepoint.
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// Convenience typedef that checks whether the passed in type is integral (i.e.
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// bool, char, int or their extended versions) and is of the correct size.
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template <typename Char, size_t N>
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using EnableIfBitsAre = std::enable_if_t<std::is_integral<Char>::value &&
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CHAR_BIT * sizeof(Char) == N,
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bool>;
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template <typename Char, EnableIfBitsAre<Char, 8> = true>
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void UnicodeAppendUnsafe(Char* out, int32_t* size, uint32_t code_point) {
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CBU8_APPEND_UNSAFE(out, *size, code_point);
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}
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template <typename Char, EnableIfBitsAre<Char, 16> = true>
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void UnicodeAppendUnsafe(Char* out, int32_t* size, uint32_t code_point) {
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CBU16_APPEND_UNSAFE(out, *size, code_point);
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}
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template <typename Char, EnableIfBitsAre<Char, 32> = true>
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void UnicodeAppendUnsafe(Char* out, int32_t* size, uint32_t code_point) {
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out[(*size)++] = code_point;
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}
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// DoUTFConversion ------------------------------------------------------------
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// Main driver of UTFConversion specialized for different Src encodings.
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// dest has to have enough room for the converted text.
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template <typename DestChar>
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bool DoUTFConversion(const char* src,
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int32_t src_len,
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DestChar* dest,
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int32_t* dest_len) {
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bool success = true;
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for (int32_t i = 0; i < src_len;) {
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int32_t code_point;
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CBU8_NEXT(src, i, src_len, code_point);
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if (!IsValidCodepoint(code_point)) {
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success = false;
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code_point = kErrorCodePoint;
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}
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UnicodeAppendUnsafe(dest, dest_len, code_point);
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}
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return success;
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}
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template <typename DestChar>
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bool DoUTFConversion(const char16* src,
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int32_t src_len,
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DestChar* dest,
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int32_t* dest_len) {
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bool success = true;
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auto ConvertSingleChar = [&success](char16 in) -> int32_t {
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if (!CBU16_IS_SINGLE(in) || !IsValidCodepoint(in)) {
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success = false;
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return kErrorCodePoint;
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}
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return in;
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};
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int32_t i = 0;
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// Always have another symbol in order to avoid checking boundaries in the
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// middle of the surrogate pair.
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while (i < src_len - 1) {
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int32_t code_point;
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if (CBU16_IS_LEAD(src[i]) && CBU16_IS_TRAIL(src[i + 1])) {
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code_point = CBU16_GET_SUPPLEMENTARY(src[i], src[i + 1]);
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if (!IsValidCodepoint(code_point)) {
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code_point = kErrorCodePoint;
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success = false;
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}
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i += 2;
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} else {
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code_point = ConvertSingleChar(src[i]);
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++i;
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}
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UnicodeAppendUnsafe(dest, dest_len, code_point);
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}
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if (i < src_len)
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UnicodeAppendUnsafe(dest, dest_len, ConvertSingleChar(src[i]));
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return success;
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}
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#if defined(WCHAR_T_IS_UTF32)
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template <typename DestChar>
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bool DoUTFConversion(const wchar_t* src,
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int32_t src_len,
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DestChar* dest,
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int32_t* dest_len) {
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bool success = true;
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for (int32_t i = 0; i < src_len; ++i) {
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int32_t code_point = src[i];
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if (!IsValidCodepoint(code_point)) {
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success = false;
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code_point = kErrorCodePoint;
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}
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UnicodeAppendUnsafe(dest, dest_len, code_point);
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}
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return success;
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}
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#endif // defined(WCHAR_T_IS_UTF32)
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// UTFConversion --------------------------------------------------------------
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// Function template for generating all UTF conversions.
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template <typename InputString, typename DestString>
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bool UTFConversion(const InputString& src_str, DestString* dest_str) {
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if (IsStringASCII(src_str)) {
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dest_str->assign(src_str.begin(), src_str.end());
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return true;
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}
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dest_str->resize(src_str.length() *
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size_coefficient_v<typename InputString::value_type,
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typename DestString::value_type>);
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// Empty string is ASCII => it OK to call operator[].
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auto* dest = &(*dest_str)[0];
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// ICU requires 32 bit numbers.
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int32_t src_len32 = static_cast<int32_t>(src_str.length());
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int32_t dest_len32 = 0;
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bool res = DoUTFConversion(src_str.data(), src_len32, dest, &dest_len32);
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dest_str->resize(dest_len32);
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dest_str->shrink_to_fit();
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return res;
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}
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} // namespace
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// UTF16 <-> UTF8 --------------------------------------------------------------
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bool UTF8ToUTF16(const char* src, size_t src_len, string16* output) {
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return UTFConversion(StringPiece(src, src_len), output);
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}
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string16 UTF8ToUTF16(StringPiece utf8) {
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string16 ret;
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// Ignore the success flag of this call, it will do the best it can for
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// invalid input, which is what we want here.
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UTF8ToUTF16(utf8.data(), utf8.size(), &ret);
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return ret;
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}
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bool UTF16ToUTF8(const char16* src, size_t src_len, std::string* output) {
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return UTFConversion(StringPiece16(src, src_len), output);
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}
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std::string UTF16ToUTF8(StringPiece16 utf16) {
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std::string ret;
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// Ignore the success flag of this call, it will do the best it can for
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// invalid input, which is what we want here.
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UTF16ToUTF8(utf16.data(), utf16.length(), &ret);
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return ret;
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}
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// UTF-16 <-> Wide -------------------------------------------------------------
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#if defined(WCHAR_T_IS_UTF16)
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// When wide == UTF-16 the conversions are a NOP.
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bool WideToUTF16(const wchar_t* src, size_t src_len, string16* output) {
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output->assign(src, src + src_len);
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return true;
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}
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string16 WideToUTF16(WStringPiece wide) {
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return string16(wide.begin(), wide.end());
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}
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bool UTF16ToWide(const char16* src, size_t src_len, std::wstring* output) {
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output->assign(src, src + src_len);
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return true;
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}
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std::wstring UTF16ToWide(StringPiece16 utf16) {
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return std::wstring(utf16.begin(), utf16.end());
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}
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#elif defined(WCHAR_T_IS_UTF32)
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bool WideToUTF16(const wchar_t* src, size_t src_len, string16* output) {
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return UTFConversion(base::WStringPiece(src, src_len), output);
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}
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string16 WideToUTF16(WStringPiece wide) {
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string16 ret;
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// Ignore the success flag of this call, it will do the best it can for
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// invalid input, which is what we want here.
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WideToUTF16(wide.data(), wide.length(), &ret);
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return ret;
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}
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bool UTF16ToWide(const char16* src, size_t src_len, std::wstring* output) {
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return UTFConversion(StringPiece16(src, src_len), output);
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}
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std::wstring UTF16ToWide(StringPiece16 utf16) {
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std::wstring ret;
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// Ignore the success flag of this call, it will do the best it can for
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// invalid input, which is what we want here.
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UTF16ToWide(utf16.data(), utf16.length(), &ret);
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return ret;
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}
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#endif // defined(WCHAR_T_IS_UTF32)
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// UTF-8 <-> Wide --------------------------------------------------------------
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// UTF8ToWide is the same code, regardless of whether wide is 16 or 32 bits
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bool UTF8ToWide(const char* src, size_t src_len, std::wstring* output) {
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return UTFConversion(StringPiece(src, src_len), output);
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}
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std::wstring UTF8ToWide(StringPiece utf8) {
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std::wstring ret;
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// Ignore the success flag of this call, it will do the best it can for
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// invalid input, which is what we want here.
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UTF8ToWide(utf8.data(), utf8.length(), &ret);
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return ret;
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}
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#if defined(WCHAR_T_IS_UTF16)
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// Easy case since we can use the "utf" versions we already wrote above.
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bool WideToUTF8(const wchar_t* src, size_t src_len, std::string* output) {
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return UTF16ToUTF8(as_u16cstr(src), src_len, output);
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}
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std::string WideToUTF8(WStringPiece wide) {
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return UTF16ToUTF8(StringPiece16(as_u16cstr(wide), wide.size()));
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}
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#elif defined(WCHAR_T_IS_UTF32)
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bool WideToUTF8(const wchar_t* src, size_t src_len, std::string* output) {
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return UTFConversion(WStringPiece(src, src_len), output);
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}
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std::string WideToUTF8(WStringPiece wide) {
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std::string ret;
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// Ignore the success flag of this call, it will do the best it can for
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// invalid input, which is what we want here.
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WideToUTF8(wide.data(), wide.length(), &ret);
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return ret;
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}
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#endif // defined(WCHAR_T_IS_UTF32)
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string16 ASCIIToUTF16(StringPiece ascii) {
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DCHECK(IsStringASCII(ascii)) << ascii;
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return string16(ascii.begin(), ascii.end());
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}
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std::string UTF16ToASCII(StringPiece16 utf16) {
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DCHECK(IsStringASCII(utf16)) << UTF16ToUTF8(utf16);
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return std::string(utf16.begin(), utf16.end());
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}
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} // namespace base
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