91 lines
2.9 KiB
C++
91 lines
2.9 KiB
C++
// Copyright (c) 2011 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/i18n/case_conversion.h"
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#include <stdint.h>
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#include "base/numerics/safe_conversions.h"
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#include "base/strings/string16.h"
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#include "base/strings/string_util.h"
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#include "third_party/icu/source/common/unicode/uchar.h"
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#include "third_party/icu/source/common/unicode/unistr.h"
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#include "third_party/icu/source/common/unicode/ustring.h"
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namespace base {
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namespace i18n {
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namespace {
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// Provides a uniform interface for upper/lower/folding which take take
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// slightly varying parameters.
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typedef int32_t (*CaseMapperFunction)(UChar* dest, int32_t dest_capacity,
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const UChar* src, int32_t src_length,
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UErrorCode* error);
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int32_t ToUpperMapper(UChar* dest, int32_t dest_capacity,
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const UChar* src, int32_t src_length,
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UErrorCode* error) {
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// Use default locale.
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return u_strToUpper(dest, dest_capacity, src, src_length, nullptr, error);
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}
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int32_t ToLowerMapper(UChar* dest, int32_t dest_capacity,
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const UChar* src, int32_t src_length,
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UErrorCode* error) {
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// Use default locale.
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return u_strToLower(dest, dest_capacity, src, src_length, nullptr, error);
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}
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int32_t FoldCaseMapper(UChar* dest, int32_t dest_capacity,
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const UChar* src, int32_t src_length,
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UErrorCode* error) {
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return u_strFoldCase(dest, dest_capacity, src, src_length,
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U_FOLD_CASE_DEFAULT, error);
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}
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// Provides similar functionality as UnicodeString::caseMap but on string16.
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string16 CaseMap(StringPiece16 string, CaseMapperFunction case_mapper) {
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string16 dest;
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if (string.empty())
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return dest;
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// Provide an initial guess that the string length won't change. The typical
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// strings we use will very rarely change length in this process, so don't
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// optimize for that case.
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dest.resize(string.size());
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UErrorCode error;
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do {
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error = U_ZERO_ERROR;
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// ICU won't terminate the string if there's not enough room for the null
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// terminator, but will otherwise. So we don't need to save room for that.
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// Don't use WriteInto, which assumes null terminators.
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int32_t new_length = case_mapper(
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&dest[0], saturated_cast<int32_t>(dest.size()),
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string.data(), saturated_cast<int32_t>(string.size()),
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&error);
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dest.resize(new_length);
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} while (error == U_BUFFER_OVERFLOW_ERROR);
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return dest;
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}
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} // namespace
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string16 ToLower(StringPiece16 string) {
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return CaseMap(string, &ToLowerMapper);
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}
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string16 ToUpper(StringPiece16 string) {
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return CaseMap(string, &ToUpperMapper);
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}
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string16 FoldCase(StringPiece16 string) {
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return CaseMap(string, &FoldCaseMapper);
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}
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} // namespace i18n
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} // namespace base
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