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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.
#ifndef BASE_I18N_CHAR_ITERATOR_H_
#define BASE_I18N_CHAR_ITERATOR_H_
#include <stddef.h>
#include <stdint.h>
#include <string>
#include "base/gtest_prod_util.h"
#include "base/i18n/base_i18n_export.h"
#include "base/macros.h"
#include "base/strings/string16.h"
#include "build/build_config.h"
// The CharIterator classes iterate through the characters in UTF8 and
// UTF16 strings. Example usage:
//
// UTF8CharIterator iter(&str);
// while (!iter.end()) {
// VLOG(1) << iter.get();
// iter.Advance();
// }
#if defined(OS_WIN)
typedef unsigned char uint8_t;
#endif
namespace base {
namespace i18n {
class BASE_I18N_EXPORT UTF8CharIterator {
public:
// Requires |str| to live as long as the UTF8CharIterator does.
explicit UTF8CharIterator(const std::string* str);
~UTF8CharIterator();
// Return the starting array index of the current character within the
// string.
int32_t array_pos() const { return array_pos_; }
// Return the logical index of the current character, independent of the
// number of bytes each character takes.
int32_t char_pos() const { return char_pos_; }
// Return the current char.
int32_t get() const { return char_; }
// Returns true if we're at the end of the string.
bool end() const { return array_pos_ == len_; }
// Advance to the next actual character. Returns false if we're at the
// end of the string.
bool Advance();
private:
// The string we're iterating over.
const uint8_t* str_;
// The length of the encoded string.
int32_t len_;
// Array index.
int32_t array_pos_;
// The next array index.
int32_t next_pos_;
// Character index.
int32_t char_pos_;
// The current character.
int32_t char_;
DISALLOW_COPY_AND_ASSIGN(UTF8CharIterator);
};
class BASE_I18N_EXPORT UTF16CharIterator {
public:
// Requires |str| to live as long as the UTF16CharIterator does.
explicit UTF16CharIterator(const string16* str);
UTF16CharIterator(const char16* str, size_t str_len);
UTF16CharIterator(UTF16CharIterator&& to_move);
~UTF16CharIterator();
UTF16CharIterator& operator=(UTF16CharIterator&& to_move);
// Returns an iterator starting on the unicode character at offset
// |array_index| into the string, or the previous array offset if
// |array_index| is the second half of a surrogate pair.
static UTF16CharIterator LowerBound(const string16* str, size_t array_index);
static UTF16CharIterator LowerBound(const char16* str,
size_t str_len,
size_t array_index);
// Returns an iterator starting on the unicode character at offset
// |array_index| into the string, or the next offset if |array_index| is the
// second half of a surrogate pair.
static UTF16CharIterator UpperBound(const string16* str, size_t array_index);
static UTF16CharIterator UpperBound(const char16* str,
size_t str_len,
size_t array_index);
// Return the starting array index of the current character within the
// string.
int32_t array_pos() const { return array_pos_; }
// Returns the offset in code points from the initial iterator position, which
// could be negative if Rewind() is called. The initial value is always zero,
// regardless of how the iterator is constructed.
int32_t char_offset() const { return char_offset_; }
// Returns the code point at the current position.
int32_t get() const { return char_; }
// Returns the code point (i.e. the full Unicode character, not half of a
// surrogate pair) following the current one. Should not be called if end() is
// true. If the current code point is the last one in the string, returns
// zero.
int32_t NextCodePoint() const;
// Returns the code point (i.e. the full Unicode character, not half of a
// surrogate pair) preceding the current one. Should not be called if start()
// is true.
int32_t PreviousCodePoint() const;
// Returns true if we're at the start of the string.
bool start() const { return array_pos_ == 0; }
// Returns true if we're at the end of the string.
bool end() const { return array_pos_ == len_; }
// Advances to the next actual character. Returns false if we're at the
// end of the string.
bool Advance();
// Moves to the previous actual character. Returns false if we're at the start
// of the string.
bool Rewind();
private:
UTF16CharIterator(const string16* str, int32_t initial_pos);
UTF16CharIterator(const char16* str, size_t str_len, int32_t initial_pos);
// Fills in the current character we found and advances to the next
// character, updating all flags as necessary.
void ReadChar();
// The string we're iterating over.
const char16* str_;
// The length of the encoded string.
int32_t len_;
// Array index.
int32_t array_pos_;
// The next array index.
int32_t next_pos_;
// Character offset from the initial position of the iterator.
int32_t char_offset_;
// The current character.
int32_t char_;
DISALLOW_COPY_AND_ASSIGN(UTF16CharIterator);
};
} // namespace i18n
} // namespace base
#endif // BASE_I18N_CHAR_ITERATOR_H_
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