Dogcows Code - chaz/openbox/blob - otk/ustring.hh

   1 // -*- mode: C++; indent-tabs-mode: nil; c-basic-offset: 2; -*-
   2 #ifndef   __ustring_hh
   3 #define   __ustring_hh
   4
   5 /*! @file ustring.hh
   6   @brief Provides a simple UTF-8 encoded string
   7 */
   8
   9 extern "C" {
  10 #ifdef HAVE_STDINT_H
  11 #  include <stdint.h>
  12 #else
  13 #  ifdef HAVE_SYS_TYPES_H
  14 #    include <sys/types.h>
  15 #  endif
  16 #endif
  17 }
  18
  19 #include <string>
  20
  21 namespace otk {
  22
  23 //! The number of bytes to skip to find the next character in the string
  24 const char g_utf8_skip[256] = {
  25   1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
  26   1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
  27   1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
  28   1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
  29   1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
  30   1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
  31   2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
  32   3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,4,4,4,4,4,4,4,4,5,5,5,5,6,6,1,1
  33 };
  34
  35 #ifdef HAVE_STDINT_H
  36 typedef uint32_t unichar;
  37 #else
  38 typedef u_int32_t unichar;
  39 #endif
  40
  41 //! The iterator type for ustring
  42 /*!
  43   Note this is not a random access iterator but a bidirectional one, since all
  44   index operations need to iterate over the UTF-8 data.  Use std::advance() to
  45   move to a certain position.
  46   <p>
  47   A writeable iterator isn't provided because:  The number of bytes of the old
  48   UTF-8 character and the new one to write could be different. Therefore, any
  49   write operation would invalidate all other iterators pointing into the same
  50   string.
  51 */
  52 template <class T>
  53 class ustring_Iterator
  54 {
  55 public:
  56   typedef std::bidirectional_iterator_tag   iterator_category;
  57   typedef unichar                           value_type;
  58   typedef std::string::difference_type      difference_type;
  59   typedef value_type                        reference;
  60   typedef void                              pointer;
  61
  62   inline ustring_Iterator() {}
  63   inline ustring_Iterator(const ustring_Iterator<std::string::iterator>&
  64                           other) : _pos(other.base()) {}
  65
  66   inline value_type operator*() const {
  67     // get a unicode character from the iterator's position
  68
  69     // get an iterator to the internal string
  70     std::string::const_iterator pos = _pos;
  71
  72     unichar result = static_cast<unsigned char>(*pos);
  73
  74     // if its not a 7-bit ascii character
  75     if((result & 0x80) != 0) {
  76       // len is the number of bytes this character takes up in the string
  77       unsigned char len = g_utf8_skip[result];
  78       result &= 0x7F >> len;
  79
  80       while(--len != 0) {
  81         result <<= 6;
  82         result |= static_cast<unsigned char>(*++pos) & 0x3F;
  83       }
  84     }
  85
  86     return result;
  87   }
  88
  89   inline ustring_Iterator<T> &     operator++() {
  90     pos_ += g_utf8_skip[static_cast<unsigned char>(*pos_)];
  91     return *this;
  92   }
  93   inline ustring_Iterator<T> &     operator--() {
  94     do { --_pos; } while((*_pos & '\xC0') == '\x80');
  95     return *this;
  96   }
  97
  98   explicit inline ustring_Iterator(T pos) : _pos(pos) {}
  99   inline T base() const { return _pos; }
 100
 101 private:
 102   T _pos;
 103 };
 104
 105 //! This class provides a simple wrapper to a std::string that is encoded as
 106 //! UTF-8.
 107 /*!
 108   This class does <b>not</b> handle extended 8-bit ASCII charsets like
 109   ISO-8859-1.
 110   <p>
 111   More info on Unicode and UTF-8 can be found here:
 112   http://www.cl.cam.ac.uk/~mgk25/unicode.html
 113   <p>
 114   This does not subclass std::string, because std::string was intended to be a
 115   final class.  For instance, it does not have a virtual destructor.
 116 */
 117 class ustring {
 118   std::string _string;
 119
 120 public:
 121   typedef std::string::size_type                        size_type;
 122   typedef std::string::difference_type                  difference_type;
 123
 124   typedef unichar                                       value_type;
 125   typedef unichar &                                     reference;
 126   typedef const unichar &                               const_reference;
 127
 128   typedef ustring_Iterator<std::string::iterator>       iterator;
 129   typedef ustring_Iterator<std::string::const_iterator> const_iterator;
 130
 131   static const size_type npos = std::string::npos;
 132
 133   ustring();
 134   ~ustring();
 135
 136   // make new strings
 137
 138   ustring(const ustring& other);
 139   ustring& operator=(const ustring& other);
 140   ustring(const std::string& src);
 141   ustring::ustring(const char* src);
 142
 143
 144 };
 145
 146 }
 147
 148 #endif // __ustring_hh