vendor/utfcpp/utf8/unchecked.h

   1 // Copyright 2006 Nemanja Trifunovic
   2
   3 /*
   4 Permission is hereby granted, free of charge, to any person or organization
   5 obtaining a copy of the software and accompanying documentation covered by
   6 this license (the "Software") to use, reproduce, display, distribute,
   7 execute, and transmit the Software, and to prepare derivative works of the
   8 Software, and to permit third-parties to whom the Software is furnished to
   9 do so, all subject to the following:
  10
  11 The copyright notices in the Software and this entire statement, including
  12 the above license grant, this restriction and the following disclaimer,
  13 must be included in all copies of the Software, in whole or in part, and
  14 all derivative works of the Software, unless such copies or derivative
  15 works are solely in the form of machine-executable object code generated by
  16 a source language processor.
  17
  18 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20 FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
  21 SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
  22 FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
  23 ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  24 DEALINGS IN THE SOFTWARE.
  25 */
  26
  27
  28 #ifndef UTF8_FOR_CPP_UNCHECKED_H_2675DCD0_9480_4c0c_B92A_CC14C027B731
  29 #define UTF8_FOR_CPP_UNCHECKED_H_2675DCD0_9480_4c0c_B92A_CC14C027B731
  30
  31 #include "core.h"
  32
  33 namespace utf8
  34 {
  35     namespace unchecked
  36     {
  37         template <typename octet_iterator>
  38         octet_iterator append(uint32_t cp, octet_iterator result)
  39         {
  40             if (cp < 0x80)                        // one octet
  41                 *(result++) = static_cast<uint8_t>(cp);
  42             else if (cp < 0x800) {                // two octets
  43                 *(result++) = static_cast<uint8_t>((cp >> 6)          | 0xc0);
  44                 *(result++) = static_cast<uint8_t>((cp & 0x3f)        | 0x80);
  45             }
  46             else if (cp < 0x10000) {              // three octets
  47                 *(result++) = static_cast<uint8_t>((cp >> 12)         | 0xe0);
  48                 *(result++) = static_cast<uint8_t>(((cp >> 6) & 0x3f) | 0x80);
  49                 *(result++) = static_cast<uint8_t>((cp & 0x3f)        | 0x80);
  50             }
  51             else {                                // four octets
  52                 *(result++) = static_cast<uint8_t>((cp >> 18)         | 0xf0);
  53                 *(result++) = static_cast<uint8_t>(((cp >> 12) & 0x3f)| 0x80);
  54                 *(result++) = static_cast<uint8_t>(((cp >> 6) & 0x3f) | 0x80);
  55                 *(result++) = static_cast<uint8_t>((cp & 0x3f)        | 0x80);
  56             }
  57             return result;
  58         }
  59
  60         template <typename octet_iterator>
  61         uint32_t next(octet_iterator& it)
  62         {
  63             uint32_t cp = utf8::internal::mask8(*it);
  64             typename std::iterator_traits<octet_iterator>::difference_type length = utf8::internal::sequence_length(it);
  65             switch (length) {
  66                 case 1:
  67                     break;
  68                 case 2:
  69                     it++;
  70                     cp = ((cp << 6) & 0x7ff) + ((*it) & 0x3f);
  71                     break;
  72                 case 3:
  73                     ++it;
  74                     cp = ((cp << 12) & 0xffff) + ((utf8::internal::mask8(*it) << 6) & 0xfff);
  75                     ++it;
  76                     cp += (*it) & 0x3f;
  77                     break;
  78                 case 4:
  79                     ++it;
  80                     cp = ((cp << 18) & 0x1fffff) + ((utf8::internal::mask8(*it) << 12) & 0x3ffff);
  81                     ++it;
  82                     cp += (utf8::internal::mask8(*it) << 6) & 0xfff;
  83                     ++it;
  84                     cp += (*it) & 0x3f;
  85                     break;
  86             }
  87             ++it;
  88             return cp;
  89         }
  90
  91         template <typename octet_iterator>
  92         uint32_t peek_next(octet_iterator it)
  93         {
  94             return utf8::unchecked::next(it);
  95         }
  96
  97         template <typename octet_iterator>
  98         uint32_t prior(octet_iterator& it)
  99         {
 100             while (utf8::internal::is_trail(*(--it))) ;
 101             octet_iterator temp = it;
 102             return utf8::unchecked::next(temp);
 103         }
 104
 105         template <typename octet_iterator, typename distance_type>
 106         void advance (octet_iterator& it, distance_type n)
 107         {
 108             const distance_type zero(0);
 109             if (n < zero) {
 110                 // backward
 111                 for (distance_type i = n; i < zero; ++i)
 112                     utf8::unchecked::prior(it);
 113             } else {
 114                 // forward
 115                 for (distance_type i = zero; i < n; ++i)
 116                     utf8::unchecked::next(it);
 117             }
 118         }
 119
 120         template <typename octet_iterator>
 121         typename std::iterator_traits<octet_iterator>::difference_type
 122         distance (octet_iterator first, octet_iterator last)
 123         {
 124             typename std::iterator_traits<octet_iterator>::difference_type dist;
 125             for (dist = 0; first < last; ++dist)
 126                 utf8::unchecked::next(first);
 127             return dist;
 128         }
 129
 130         template <typename u16bit_iterator, typename octet_iterator>
 131         octet_iterator utf16to8 (u16bit_iterator start, u16bit_iterator end, octet_iterator result)
 132         {
 133             while (start != end) {
 134                 uint32_t cp = utf8::internal::mask16(*start++);
 135             // Take care of surrogate pairs first
 136                 if (utf8::internal::is_lead_surrogate(cp)) {
 137                     uint32_t trail_surrogate = utf8::internal::mask16(*start++);
 138                     cp = (cp << 10) + trail_surrogate + internal::SURROGATE_OFFSET;
 139                 }
 140                 result = utf8::unchecked::append(cp, result);
 141             }
 142             return result;
 143         }
 144
 145         template <typename u16bit_iterator, typename octet_iterator>
 146         u16bit_iterator utf8to16 (octet_iterator start, octet_iterator end, u16bit_iterator result)
 147         {
 148             while (start < end) {
 149                 uint32_t cp = utf8::unchecked::next(start);
 150                 if (cp > 0xffff) { //make a surrogate pair
 151                     *result++ = static_cast<uint16_t>((cp >> 10)   + internal::LEAD_OFFSET);
 152                     *result++ = static_cast<uint16_t>((cp & 0x3ff) + internal::TRAIL_SURROGATE_MIN);
 153                 }
 154                 else
 155                     *result++ = static_cast<uint16_t>(cp);
 156             }
 157             return result;
 158         }
 159
 160         template <typename octet_iterator, typename u32bit_iterator>
 161         octet_iterator utf32to8 (u32bit_iterator start, u32bit_iterator end, octet_iterator result)
 162         {
 163             while (start != end)
 164                 result = utf8::unchecked::append(*(start++), result);
 165
 166             return result;
 167         }
 168
 169         template <typename octet_iterator, typename u32bit_iterator>
 170         u32bit_iterator utf8to32 (octet_iterator start, octet_iterator end, u32bit_iterator result)
 171         {
 172             while (start < end)
 173                 (*result++) = utf8::unchecked::next(start);
 174
 175             return result;
 176         }
 177
 178         // The iterator class
 179         template <typename octet_iterator>
 180           class iterator : public std::iterator <std::bidirectional_iterator_tag, uint32_t> {
 181             octet_iterator it;
 182             public:
 183             iterator () {}
 184             explicit iterator (const octet_iterator& octet_it): it(octet_it) {}
 185             // the default "big three" are OK
 186             octet_iterator base () const { return it; }
 187             uint32_t operator * () const
 188             {
 189                 octet_iterator temp = it;
 190                 return utf8::unchecked::next(temp);
 191             }
 192             bool operator == (const iterator& rhs) const
 193             {
 194                 return (it == rhs.it);
 195             }
 196             bool operator != (const iterator& rhs) const
 197             {
 198                 return !(operator == (rhs));
 199             }
 200             iterator& operator ++ ()
 201             {
 202                 ::std::advance(it, utf8::internal::sequence_length(it));
 203                 return *this;
 204             }
 205             iterator operator ++ (int)
 206             {
 207                 iterator temp = *this;
 208                 ::std::advance(it, utf8::internal::sequence_length(it));
 209                 return temp;
 210             }
 211             iterator& operator -- ()
 212             {
 213                 utf8::unchecked::prior(it);
 214                 return *this;
 215             }
 216             iterator operator -- (int)
 217             {
 218                 iterator temp = *this;
 219                 utf8::unchecked::prior(it);
 220                 return temp;
 221             }
 222           }; // class iterator
 223
 224     } // namespace utf8::unchecked
 225 } // namespace utf8
 226
 227
 228 #endif // header guard
 229