Repo created

TMessagesProj/jni/voip/webrtc/base/i18n/case_conversion.cc

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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 "base/numerics/safe_conversions.h"
+#include "base/strings/string16.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 string16.
+string16 CaseMap(StringPiece16 string, CaseMapperFunction case_mapper) {
+  string16 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
+
+string16 ToLower(StringPiece16 string) {
+  return CaseMap(string, &ToLowerMapper);
+}
+
+string16 ToUpper(StringPiece16 string) {
+  return CaseMap(string, &ToUpperMapper);
+}
+
+string16 FoldCase(StringPiece16 string) {
+  return CaseMap(string, &FoldCaseMapper);
+}
+
+}  // namespace i18n
+}  // namespace base