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- // Copyright (c) 2011 The Chromium Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style license that can be
- // found in the LICENSE file.
- #include "base/i18n/case_conversion.h"
- #include <stdint.h>
- #include <string>
- #include "base/numerics/safe_conversions.h"
- #include "base/strings/string_util.h"
- #include "third_party/icu/source/common/unicode/uchar.h"
- #include "third_party/icu/source/common/unicode/unistr.h"
- #include "third_party/icu/source/common/unicode/ustring.h"
- namespace base {
- namespace i18n {
- namespace {
- // Provides a uniform interface for upper/lower/folding which take take
- // slightly varying parameters.
- typedef int32_t (*CaseMapperFunction)(UChar* dest, int32_t dest_capacity,
- const UChar* src, int32_t src_length,
- UErrorCode* error);
- int32_t ToUpperMapper(UChar* dest, int32_t dest_capacity,
- const UChar* src, int32_t src_length,
- UErrorCode* error) {
- // Use default locale.
- return u_strToUpper(dest, dest_capacity, src, src_length, nullptr, error);
- }
- int32_t ToLowerMapper(UChar* dest, int32_t dest_capacity,
- const UChar* src, int32_t src_length,
- UErrorCode* error) {
- // Use default locale.
- return u_strToLower(dest, dest_capacity, src, src_length, nullptr, error);
- }
- int32_t FoldCaseMapper(UChar* dest, int32_t dest_capacity,
- const UChar* src, int32_t src_length,
- UErrorCode* error) {
- return u_strFoldCase(dest, dest_capacity, src, src_length,
- U_FOLD_CASE_DEFAULT, error);
- }
- // Provides similar functionality as UnicodeString::caseMap but on
- // std::u16string.
- std::u16string CaseMap(StringPiece16 string, CaseMapperFunction case_mapper) {
- std::u16string dest;
- if (string.empty())
- return dest;
- // Provide an initial guess that the string length won't change. The typical
- // strings we use will very rarely change length in this process, so don't
- // optimize for that case.
- dest.resize(string.size());
- UErrorCode error;
- do {
- error = U_ZERO_ERROR;
- // ICU won't terminate the string if there's not enough room for the null
- // terminator, but will otherwise. So we don't need to save room for that.
- // Don't use WriteInto, which assumes null terminators.
- int32_t new_length = case_mapper(
- &dest[0], saturated_cast<int32_t>(dest.size()), string.data(),
- saturated_cast<int32_t>(string.size()), &error);
- dest.resize(new_length);
- } while (error == U_BUFFER_OVERFLOW_ERROR);
- return dest;
- }
- } // namespace
- std::u16string ToLower(StringPiece16 string) {
- return CaseMap(string, &ToLowerMapper);
- }
- std::u16string ToUpper(StringPiece16 string) {
- return CaseMap(string, &ToUpperMapper);
- }
- std::u16string FoldCase(StringPiece16 string) {
- return CaseMap(string, &FoldCaseMapper);
- }
- } // namespace i18n
- } // namespace base
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