1
    2
    3
    4
    5
    6
    7
    8
    9
   10
   11
   12
   13
   14
   15
   16
   17
   18
   19
   20
   21
   22
   23
   24
   25
   26
   27
   28
   29
   30
   31
   32
   33
   34
   35
   36
   37
   38
   39
   40
   41
   42
   43
   44
   45
   46
   47
   48
   49
   50
   51
   52
   53
   54
   55
   56
   57
   58
   59
   60
   61
   62
   63
   64
   65
   66
   67
   68
   69
   70
   71
   72
   73
   74
   75
   76
   77
   78
   79
   80
   81
   82
   83
   84
   85
   86
   87
   88
   89
   90
   91
   92
   93
   94
   95
   96
   97
   98
   99
  100
  101
  102
  103
  104
  105
  106
  107
  108
  109
  110
  111
  112
  113
  114
  115
  116
  117
  118
  119
  120
  121
  122
  123
  124
  125
  126
  127
  128
  129


base / i18n / char_iterator.cc [blame]

// Copyright 2011 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/40284755): Remove this and spanify to fix the errors.
#pragma allow_unsafe_buffers
#endif

#include "base/i18n/char_iterator.h"

#include <string_view>

#include "base/check_op.h"
#include "base/third_party/icu/icu_utf.h"

namespace base {
namespace i18n {

// UTF8CharIterator ------------------------------------------------------------

UTF8CharIterator::UTF8CharIterator(std::string_view str)
    : str_(str), array_pos_(0), next_pos_(0), char_pos_(0), char_(0) {
  if (!str_.empty())
    CBU8_NEXT(str_.data(), next_pos_, str_.length(), char_);
}

UTF8CharIterator::~UTF8CharIterator() = default;

bool UTF8CharIterator::Advance() {
  if (array_pos_ >= str_.length())
    return false;

  array_pos_ = next_pos_;
  char_pos_++;
  if (next_pos_ < str_.length())
    CBU8_NEXT(str_.data(), next_pos_, str_.length(), char_);

  return true;
}

// UTF16CharIterator -----------------------------------------------------------

UTF16CharIterator::UTF16CharIterator(std::u16string_view str)
    : UTF16CharIterator(str, 0) {}

UTF16CharIterator::UTF16CharIterator(UTF16CharIterator&& to_move) = default;

UTF16CharIterator::~UTF16CharIterator() = default;

UTF16CharIterator& UTF16CharIterator::operator=(UTF16CharIterator&& to_move) =
    default;

// static
UTF16CharIterator UTF16CharIterator::LowerBound(std::u16string_view str,
                                                size_t array_index) {
  DCHECK_LE(array_index, str.length());
  CBU16_SET_CP_START(str.data(), 0, array_index);
  return UTF16CharIterator(str, array_index);
}

// static
UTF16CharIterator UTF16CharIterator::UpperBound(std::u16string_view str,
                                                size_t array_index) {
  DCHECK_LE(array_index, str.length());
  CBU16_SET_CP_LIMIT(str.data(), 0, array_index, str.length());
  return UTF16CharIterator(str, array_index);
}

int32_t UTF16CharIterator::NextCodePoint() const {
  if (next_pos_ >= str_.length())
    return 0;

  base_icu::UChar32 c;
  CBU16_GET(str_.data(), 0, next_pos_, str_.length(), c);
  return c;
}

int32_t UTF16CharIterator::PreviousCodePoint() const {
  if (array_pos_ == 0)
    return 0;

  uint32_t pos = array_pos_;
  base_icu::UChar32 c;
  CBU16_PREV(str_.data(), 0, pos, c);
  return c;
}

bool UTF16CharIterator::Advance() {
  if (array_pos_ >= str_.length())
    return false;

  array_pos_ = next_pos_;
  char_offset_++;
  if (next_pos_ < str_.length())
    ReadChar();

  return true;
}

bool UTF16CharIterator::Rewind() {
  if (array_pos_ == 0)
    return false;

  next_pos_ = array_pos_;
  char_offset_--;
  CBU16_PREV(str_.data(), 0, array_pos_, char_);
  return true;
}

UTF16CharIterator::UTF16CharIterator(std::u16string_view str,
                                     size_t initial_pos)
    : str_(str),
      array_pos_(initial_pos),
      next_pos_(initial_pos),
      char_offset_(0),
      char_(0) {
  // This has the side-effect of advancing |next_pos_|.
  if (array_pos_ < str_.length())
    ReadChar();
}

void UTF16CharIterator::ReadChar() {
  // This is actually a huge macro, so is worth having in a separate function.
  CBU16_NEXT(str_.data(), next_pos_, str_.length(), char_);
}

}  // namespace i18n
}  // namespace base