Add functions to get the length or compute a substring of UTF8 and UTF16

encoded strings.

BUG=none
TEST=Added new unit tests for each.

Review URL: http://codereview.chromium.org/3133028

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@57051 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 58 insertions, 0 deletions

diff --git a/base/i18n/char_iterator.cc b/base/i18n/char_iterator.cc
new file mode 100644
index 0000000..c323c5d
--- /dev/null
+++ b/base/i18n/char_iterator.cc
@@ -0,0 +1,58 @@
+// Copyright (c) 2010 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/char_iterator.h"
+
+#include "unicode/utf8.h"
+#include "unicode/utf16.h"
+
+namespace base {
+
+UTF8CharIterator::UTF8CharIterator(const std::string* str)
+    : str_(reinterpret_cast<const uint8_t*>(str->data())),
+      len_(str->size()),
+      array_pos_(0),
+      next_pos_(0),
+      char_pos_(0),
+      char_(0) {
+  if (len_)
+    U8_NEXT(str_, next_pos_, len_, char_);
+}
+
+bool UTF8CharIterator::Advance() {
+  if (array_pos_ >= len_)
+    return false;
+
+  array_pos_ = next_pos_;
+  char_pos_++;
+  if (next_pos_ < len_)
+    U8_NEXT(str_, next_pos_, len_, char_);
+
+  return true;
+}
+
+UTF16CharIterator::UTF16CharIterator(const string16* str)
+    : str_(reinterpret_cast<const char16*>(str->data())),
+      len_(str->size()),
+      array_pos_(0),
+      next_pos_(0),
+      char_pos_(0),
+      char_(0) {
+  if (len_)
+    U16_NEXT(str_, next_pos_, len_, char_);
+}
+
+bool UTF16CharIterator::Advance() {
+  if (array_pos_ >= len_)
+    return false;
+
+  array_pos_ = next_pos_;
+  char_pos_++;
+  if (next_pos_ < len_)
+    U16_NEXT(str_, next_pos_, len_, char_);
+
+  return true;
+}
+
+}  // namespace base