// Copyright 2009 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_conversion_utils.h"
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#include "base/third_party/icu/icu_utf.h"
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namespace base {
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namespace {
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// Appends `code_point` to `*output`. Requires `*output` to be a UTF16 string.
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// Returns the number of code units written.
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template <typename StringT>
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size_t WriteUTF16Character(uint32_t code_point, StringT* output) {
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using CharT = typename StringT::value_type;
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static_assert(sizeof(CharT) == 2, "Error: *output is not a UTF16 string");
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if (CBU16_LENGTH(code_point) == 1) {
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output->push_back(static_cast<CharT>(code_point));
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return 1;
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}
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size_t char_offset = output->length();
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output->resize(char_offset + CBU16_MAX_LENGTH);
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CBU16_APPEND_UNSAFE(&(*output)[0], char_offset, code_point);
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return CBU16_MAX_LENGTH;
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}
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} // namespace
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bool ReadUnicodeCharacter(const char* src,
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int32_t src_len,
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int32_t* char_index,
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uint32_t* code_point_out) {
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int32_t code_point;
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CBU8_NEXT(src, *char_index, src_len, code_point);
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*code_point_out = static_cast<uint32_t>(code_point);
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(*char_index)--;
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return IsValidCodepoint(code_point);
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}
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bool ReadUnicodeCharacter(const char16* src,
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int32_t src_len,
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int32_t* char_index,
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uint32_t* code_point) {
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if (CBU16_IS_SURROGATE(src[*char_index])) {
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if (!CBU16_IS_SURROGATE_LEAD(src[*char_index]) ||
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*char_index + 1 >= src_len ||
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!CBU16_IS_TRAIL(src[*char_index + 1])) {
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return false;
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}
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*code_point = CBU16_GET_SUPPLEMENTARY(src[*char_index],
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src[*char_index + 1]);
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(*char_index)++;
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} else {
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*code_point = src[*char_index];
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}
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return IsValidCodepoint(*code_point);
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}
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size_t WriteUnicodeCharacter(uint32_t code_point, std::string* output) {
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if (code_point <= 0x7f) {
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output->push_back(static_cast<char>(code_point));
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return 1;
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}
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size_t char_offset = output->length();
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size_t original_char_offset = char_offset;
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output->resize(char_offset + CBU8_MAX_LENGTH);
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CBU8_APPEND_UNSAFE(&(*output)[0], char_offset, code_point);
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output->resize(char_offset);
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return char_offset - original_char_offset;
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}
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size_t WriteUnicodeCharacter(uint32_t code_point, string16* output) {
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return WriteUTF16Character(code_point, output);
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}
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template<typename CHAR>
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void PrepareForUTF8Output(const CHAR* src,
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size_t src_len,
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std::string* output) {
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output->clear();
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if (src_len == 0)
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return;
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if (src[0] < 0x80) {
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output->reserve(src_len);
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} else {
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output->reserve(src_len * 3);
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}
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}
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template void PrepareForUTF8Output(const wchar_t*, size_t, std::string*);
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template void PrepareForUTF8Output(const char16*, size_t, std::string*);
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template<typename STRING>
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void PrepareForUTF16Or32Output(const char* src,
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size_t src_len,
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STRING* output) {
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output->clear();
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if (src_len == 0)
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return;
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if (static_cast<unsigned char>(src[0]) < 0x80) {
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output->reserve(src_len);
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} else {
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output->reserve(src_len / 2);
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}
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}
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template void PrepareForUTF16Or32Output(const char*, size_t, string16*);
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} // namespace base
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