base/i18n/char_iterator.h

   1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef BASE_I18N_CHAR_ITERATOR_H_
   6 #define BASE_I18N_CHAR_ITERATOR_H_
   7
   8 #include <string>
   9
  10 #include "base/basictypes.h"
  11 #include "base/i18n/base_i18n_export.h"
  12 #include "base/strings/string16.h"
  13
  14 // The CharIterator classes iterate through the characters in UTF8 and
  15 // UTF16 strings.  Example usage:
  16 //
  17 //   UTF8CharIterator iter(&str);
  18 //   while (!iter.End()) {
  19 //     VLOG(1) << iter.get();
  20 //     iter.Advance();
  21 //   }
  22
  23 #if defined(OS_WIN)
  24 typedef unsigned char uint8_t;
  25 #endif
  26
  27 namespace base {
  28 namespace i18n {
  29
  30 class BASE_I18N_EXPORT UTF8CharIterator {
  31  public:
  32   // Requires |str| to live as long as the UTF8CharIterator does.
  33   explicit UTF8CharIterator(const std::string* str);
  34   ~UTF8CharIterator();
  35
  36   // Return the starting array index of the current character within the
  37   // string.
  38   int32 array_pos() const { return array_pos_; }
  39
  40   // Return the logical index of the current character, independent of the
  41   // number of bytes each character takes.
  42   int32 char_pos() const { return char_pos_; }
  43
  44   // Return the current char.
  45   int32 get() const { return char_; }
  46
  47   // Returns true if we're at the end of the string.
  48   bool end() const { return array_pos_ == len_; }
  49
  50   // Advance to the next actual character.  Returns false if we're at the
  51   // end of the string.
  52   bool Advance();
  53
  54  private:
  55   // The string we're iterating over.
  56   const uint8_t* str_;
  57
  58   // The length of the encoded string.
  59   int32 len_;
  60
  61   // Array index.
  62   int32 array_pos_;
  63
  64   // The next array index.
  65   int32 next_pos_;
  66
  67   // Character index.
  68   int32 char_pos_;
  69
  70   // The current character.
  71   int32 char_;
  72
  73   DISALLOW_COPY_AND_ASSIGN(UTF8CharIterator);
  74 };
  75
  76 class BASE_I18N_EXPORT UTF16CharIterator {
  77  public:
  78   // Requires |str| to live as long as the UTF16CharIterator does.
  79   explicit UTF16CharIterator(const string16* str);
  80   UTF16CharIterator(const char16* str, size_t str_len);
  81   ~UTF16CharIterator();
  82
  83   // Return the starting array index of the current character within the
  84   // string.
  85   int32 array_pos() const { return array_pos_; }
  86
  87   // Return the logical index of the current character, independent of the
  88   // number of codewords each character takes.
  89   int32 char_pos() const { return char_pos_; }
  90
  91   // Return the current char.
  92   int32 get() const { return char_; }
  93
  94   // Returns true if we're at the end of the string.
  95   bool end() const { return array_pos_ == len_; }
  96
  97   // Advance to the next actual character.  Returns false if we're at the
  98   // end of the string.
  99   bool Advance();
 100
 101  private:
 102   // Fills in the current character we found and advances to the next
 103   // character, updating all flags as necessary.
 104   void ReadChar();
 105
 106   // The string we're iterating over.
 107   const char16* str_;
 108
 109   // The length of the encoded string.
 110   int32 len_;
 111
 112   // Array index.
 113   int32 array_pos_;
 114
 115   // The next array index.
 116   int32 next_pos_;
 117
 118   // Character index.
 119   int32 char_pos_;
 120
 121   // The current character.
 122   int32 char_;
 123
 124   DISALLOW_COPY_AND_ASSIGN(UTF16CharIterator);
 125 };
 126
 127 }  // namespace i18n
 128 }  // namespace base
 129
 130 #endif  // BASE_I18N_CHAR_ITERATOR_H_