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hb-utf.hh (11163B)

      1 /*
      2 * Copyright © 2011,2012,2014  Google, Inc.
      3 *
      4 *  This is part of HarfBuzz, a text shaping library.
      5 *
      6 * Permission is hereby granted, without written agreement and without
      7 * license or royalty fees, to use, copy, modify, and distribute this
      8 * software and its documentation for any purpose, provided that the
      9 * above copyright notice and the following two paragraphs appear in
     10 * all copies of this software.
     11 *
     12 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
     13 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
     14 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
     15 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
     16 * DAMAGE.
     17 *
     18 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
     19 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
     20 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
     21 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
     22 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
     23 *
     24 * Google Author(s): Behdad Esfahbod
     25 */
     26 
     27 #ifndef HB_UTF_HH
     28 #define HB_UTF_HH
     29 
     30 #include "hb.hh"
     31 
     32 #include "hb-open-type.hh"
     33 
     34 
     35 struct hb_utf8_t
     36 {
     37  typedef uint8_t codepoint_t;
     38  static constexpr unsigned max_len = 4;
     39 
     40  static inline const codepoint_t *
     41  next (const codepoint_t *text,
     42 const codepoint_t *end,
     43 hb_codepoint_t *unicode,
     44 hb_codepoint_t replacement)
     45  {
     46    /* Written to only accept well-formed sequences.
     47     * Based on ideas from ICU's U8_NEXT.
     48     * Generates one "replacement" for each ill-formed byte. */
     49 
     50    hb_codepoint_t c = *text++;
     51 
     52    if (c > 0x7Fu)
     53    {
     54      if (hb_in_range<hb_codepoint_t> (c, 0xC2u, 0xDFu)) /* Two-byte */
     55      {
     56 unsigned int t1;
     57 if (likely (text < end &&
     58 	    (t1 = text[0] - 0x80u) <= 0x3Fu))
     59 {
     60   c = ((c&0x1Fu)<<6) | t1;
     61   text++;
     62 }
     63 else
     64   goto error;
     65      }
     66      else if (hb_in_range<hb_codepoint_t> (c, 0xE0u, 0xEFu)) /* Three-byte */
     67      {
     68 unsigned int t1, t2;
     69 if (likely (1 < end - text &&
     70 	    (t1 = text[0] - 0x80u) <= 0x3Fu &&
     71 	    (t2 = text[1] - 0x80u) <= 0x3Fu))
     72 {
     73   c = ((c&0xFu)<<12) | (t1<<6) | t2;
     74   if (unlikely (c < 0x0800u || hb_in_range<hb_codepoint_t> (c, 0xD800u, 0xDFFFu)))
     75     goto error;
     76   text += 2;
     77 }
     78 else
     79   goto error;
     80      }
     81      else if (hb_in_range<hb_codepoint_t> (c, 0xF0u, 0xF4u)) /* Four-byte */
     82      {
     83 unsigned int t1, t2, t3;
     84 if (likely (2 < end - text &&
     85 	    (t1 = text[0] - 0x80u) <= 0x3Fu &&
     86 	    (t2 = text[1] - 0x80u) <= 0x3Fu &&
     87 	    (t3 = text[2] - 0x80u) <= 0x3Fu))
     88 {
     89   c = ((c&0x7u)<<18) | (t1<<12) | (t2<<6) | t3;
     90   if (unlikely (!hb_in_range<hb_codepoint_t> (c, 0x10000u, 0x10FFFFu)))
     91     goto error;
     92   text += 3;
     93 }
     94 else
     95   goto error;
     96      }
     97      else
     98 goto error;
     99    }
    100 
    101    *unicode = c;
    102    return text;
    103 
    104  error:
    105    *unicode = replacement;
    106    return text;
    107  }
    108 
    109  static inline const codepoint_t *
    110  prev (const codepoint_t *text,
    111 const codepoint_t *start,
    112 hb_codepoint_t *unicode,
    113 hb_codepoint_t replacement)
    114  {
    115    const codepoint_t *end = text--;
    116    while (start < text && (*text & 0xc0) == 0x80 && end - text < 4)
    117      text--;
    118 
    119    if (likely (next (text, end, unicode, replacement) == end))
    120      return text;
    121 
    122    *unicode = replacement;
    123    return end - 1;
    124  }
    125 
    126  static unsigned int
    127  strlen (const codepoint_t *text)
    128  { return ::strlen ((const char *) text); }
    129 
    130  static unsigned int
    131  encode_len (hb_codepoint_t unicode)
    132  {
    133    if (unicode <   0x0080u) return 1;
    134    if (unicode <   0x0800u) return 2;
    135    if (unicode <  0x10000u) return 3;
    136    if (unicode < 0x110000u) return 4;
    137    return 3;
    138  }
    139 
    140  static codepoint_t *
    141  encode (codepoint_t *text,
    142   const codepoint_t *end,
    143   hb_codepoint_t unicode)
    144  {
    145    if (unlikely (unicode >= 0xD800u && (unicode <= 0xDFFFu || unicode > 0x10FFFFu)))
    146      unicode = 0xFFFDu;
    147    if (unicode < 0x0080u)
    148     *text++ = unicode;
    149    else if (unicode < 0x0800u)
    150    {
    151      if (end - text >= 2)
    152      {
    153 *text++ =  0xC0u + (0x1Fu & (unicode >>  6));
    154 *text++ =  0x80u + (0x3Fu & (unicode      ));
    155      }
    156    }
    157    else if (unicode < 0x10000u)
    158    {
    159      if (end - text >= 3)
    160      {
    161 *text++ =  0xE0u + (0x0Fu & (unicode >> 12));
    162 *text++ =  0x80u + (0x3Fu & (unicode >>  6));
    163 *text++ =  0x80u + (0x3Fu & (unicode      ));
    164      }
    165    }
    166    else
    167    {
    168      if (end - text >= 4)
    169      {
    170 *text++ =  0xF0u + (0x07u & (unicode >> 18));
    171 *text++ =  0x80u + (0x3Fu & (unicode >> 12));
    172 *text++ =  0x80u + (0x3Fu & (unicode >>  6));
    173 *text++ =  0x80u + (0x3Fu & (unicode      ));
    174      }
    175    }
    176    return text;
    177  }
    178 };
    179 
    180 
    181 template <typename TCodepoint>
    182 struct hb_utf16_xe_t
    183 {
    184  static_assert (sizeof (TCodepoint) == 2, "");
    185  typedef TCodepoint codepoint_t;
    186  static constexpr unsigned max_len = 2;
    187 
    188  static inline const codepoint_t *
    189  next (const codepoint_t *text,
    190 const codepoint_t *end,
    191 hb_codepoint_t *unicode,
    192 hb_codepoint_t replacement)
    193  {
    194    hb_codepoint_t c = *text++;
    195 
    196    if (likely (!hb_in_range<hb_codepoint_t> (c, 0xD800u, 0xDFFFu)))
    197    {
    198      *unicode = c;
    199      return text;
    200    }
    201 
    202    if (likely (c <= 0xDBFFu && text < end))
    203    {
    204      /* High-surrogate in c */
    205      hb_codepoint_t l = *text;
    206      if (likely (hb_in_range<hb_codepoint_t> (l, 0xDC00u, 0xDFFFu)))
    207      {
    208 /* Low-surrogate in l */
    209 *unicode = (c << 10) + l - ((0xD800u << 10) - 0x10000u + 0xDC00u);
    210  text++;
    211  return text;
    212      }
    213    }
    214 
    215    /* Lonely / out-of-order surrogate. */
    216    *unicode = replacement;
    217    return text;
    218  }
    219 
    220  static inline const codepoint_t *
    221  prev (const codepoint_t *text,
    222 const codepoint_t *start,
    223 hb_codepoint_t *unicode,
    224 hb_codepoint_t replacement)
    225  {
    226    hb_codepoint_t c = *--text;
    227 
    228    if (likely (!hb_in_range<hb_codepoint_t> (c, 0xD800u, 0xDFFFu)))
    229    {
    230      *unicode = c;
    231      return text;
    232    }
    233 
    234    if (likely (c >= 0xDC00u && start < text))
    235    {
    236      /* Low-surrogate in c */
    237      hb_codepoint_t h = text[-1];
    238      if (likely (hb_in_range<hb_codepoint_t> (h, 0xD800u, 0xDBFFu)))
    239      {
    240 /* High-surrogate in h */
    241 *unicode = (h << 10) + c - ((0xD800u << 10) - 0x10000u + 0xDC00u);
    242 text--;
    243 return text;
    244      }
    245    }
    246 
    247    /* Lonely / out-of-order surrogate. */
    248    *unicode = replacement;
    249    return text;
    250  }
    251 
    252 
    253  static unsigned int
    254  strlen (const codepoint_t *text)
    255  {
    256    unsigned int l = 0;
    257    while (*text++) l++;
    258    return l;
    259  }
    260 
    261  static unsigned int
    262  encode_len (hb_codepoint_t unicode)
    263  {
    264    return unicode < 0x10000 ? 1 : 2;
    265  }
    266 
    267  static codepoint_t *
    268  encode (codepoint_t *text,
    269   const codepoint_t *end,
    270   hb_codepoint_t unicode)
    271  {
    272    if (unlikely (unicode >= 0xD800u && (unicode <= 0xDFFFu || unicode > 0x10FFFFu)))
    273      unicode = 0xFFFDu;
    274    if (unicode < 0x10000u)
    275     *text++ = unicode;
    276    else if (end - text >= 2)
    277    {
    278      unicode -= 0x10000u;
    279      *text++ =  0xD800u + (unicode >> 10);
    280      *text++ =  0xDC00u + (unicode & 0x03FFu);
    281    }
    282    return text;
    283  }
    284 };
    285 
    286 typedef hb_utf16_xe_t<uint16_t> hb_utf16_t;
    287 typedef hb_utf16_xe_t<OT::HBUINT16> hb_utf16_be_t;
    288 
    289 
    290 template <typename TCodepoint, bool validate=true>
    291 struct hb_utf32_xe_t
    292 {
    293  static_assert (sizeof (TCodepoint) == 4, "");
    294  typedef TCodepoint codepoint_t;
    295  static constexpr unsigned max_len = 1;
    296 
    297  static inline const TCodepoint *
    298  next (const TCodepoint *text,
    299 const TCodepoint *end HB_UNUSED,
    300 hb_codepoint_t *unicode,
    301 hb_codepoint_t replacement)
    302  {
    303    hb_codepoint_t c = *unicode = *text++;
    304    if (validate && unlikely (c >= 0xD800u && (c <= 0xDFFFu || c > 0x10FFFFu)))
    305      *unicode = replacement;
    306    return text;
    307  }
    308 
    309  static inline const TCodepoint *
    310  prev (const TCodepoint *text,
    311 const TCodepoint *start HB_UNUSED,
    312 hb_codepoint_t *unicode,
    313 hb_codepoint_t replacement)
    314  {
    315    hb_codepoint_t c = *unicode = *--text;
    316    if (validate && unlikely (c >= 0xD800u && (c <= 0xDFFFu || c > 0x10FFFFu)))
    317      *unicode = replacement;
    318    return text;
    319  }
    320 
    321  static unsigned int
    322  strlen (const TCodepoint *text)
    323  {
    324    unsigned int l = 0;
    325    while (*text++) l++;
    326    return l;
    327  }
    328 
    329  static unsigned int
    330  encode_len (hb_codepoint_t unicode HB_UNUSED)
    331  {
    332    return 1;
    333  }
    334 
    335  static codepoint_t *
    336  encode (codepoint_t *text,
    337   const codepoint_t *end HB_UNUSED,
    338   hb_codepoint_t unicode)
    339  {
    340    if (validate && unlikely (unicode >= 0xD800u && (unicode <= 0xDFFFu || unicode > 0x10FFFFu)))
    341      unicode = 0xFFFDu;
    342    *text++ = unicode;
    343    return text;
    344  }
    345 };
    346 
    347 typedef hb_utf32_xe_t<uint32_t> hb_utf32_t;
    348 typedef hb_utf32_xe_t<uint32_t, false> hb_utf32_novalidate_t;
    349 
    350 
    351 struct hb_latin1_t
    352 {
    353  typedef uint8_t codepoint_t;
    354  static constexpr unsigned max_len = 1;
    355 
    356  static inline const codepoint_t *
    357  next (const codepoint_t *text,
    358 const codepoint_t *end HB_UNUSED,
    359 hb_codepoint_t *unicode,
    360 hb_codepoint_t replacement HB_UNUSED)
    361  {
    362    *unicode = *text++;
    363    return text;
    364  }
    365 
    366  static inline const codepoint_t *
    367  prev (const codepoint_t *text,
    368 const codepoint_t *start HB_UNUSED,
    369 hb_codepoint_t *unicode,
    370 hb_codepoint_t replacement HB_UNUSED)
    371  {
    372    *unicode = *--text;
    373    return text;
    374  }
    375 
    376  static unsigned int
    377  strlen (const codepoint_t *text)
    378  {
    379    unsigned int l = 0;
    380    while (*text++) l++;
    381    return l;
    382  }
    383 
    384  static unsigned int
    385  encode_len (hb_codepoint_t unicode HB_UNUSED)
    386  {
    387    return 1;
    388  }
    389 
    390  static codepoint_t *
    391  encode (codepoint_t *text,
    392   const codepoint_t *end HB_UNUSED,
    393   hb_codepoint_t unicode)
    394  {
    395    if (unlikely (unicode >= 0x0100u))
    396      unicode = '?';
    397    *text++ = unicode;
    398    return text;
    399  }
    400 };
    401 
    402 
    403 struct hb_ascii_t
    404 {
    405  typedef uint8_t codepoint_t;
    406  static constexpr unsigned max_len = 1;
    407 
    408  static inline const codepoint_t *
    409  next (const codepoint_t *text,
    410 const codepoint_t *end HB_UNUSED,
    411 hb_codepoint_t *unicode,
    412 hb_codepoint_t replacement)
    413  {
    414    *unicode = *text++;
    415    if (*unicode >= 0x0080u)
    416      *unicode = replacement;
    417    return text;
    418  }
    419 
    420  static inline const codepoint_t *
    421  prev (const codepoint_t *text,
    422 const codepoint_t *start HB_UNUSED,
    423 hb_codepoint_t *unicode,
    424 hb_codepoint_t replacement)
    425  {
    426    *unicode = *--text;
    427    if (*unicode >= 0x0080u)
    428      *unicode = replacement;
    429    return text;
    430  }
    431 
    432  static unsigned int
    433  strlen (const codepoint_t *text)
    434  {
    435    unsigned int l = 0;
    436    while (*text++) l++;
    437    return l;
    438  }
    439 
    440  static unsigned int
    441  encode_len (hb_codepoint_t unicode HB_UNUSED)
    442  {
    443    return 1;
    444  }
    445 
    446  static codepoint_t *
    447  encode (codepoint_t *text,
    448   const codepoint_t *end HB_UNUSED,
    449   hb_codepoint_t unicode)
    450  {
    451    if (unlikely (unicode >= 0x0080u))
    452      unicode = '?';
    453    *text++ = unicode;
    454    return text;
    455  }
    456 };
    457 
    458 template <typename utf_t>
    459 static inline const typename utf_t::codepoint_t *
    460 hb_utf_offset_to_pointer (const typename utf_t::codepoint_t *start,
    461 		  const typename utf_t::codepoint_t *text,
    462 		  unsigned text_len,
    463 		  signed offset)
    464 {
    465  hb_codepoint_t unicode;
    466 
    467  while (offset-- > 0)
    468    start = utf_t::next (start,
    469 		 text + text_len,
    470 		 &unicode,
    471 		 HB_BUFFER_REPLACEMENT_CODEPOINT_DEFAULT);
    472 
    473  while (offset++ < 0)
    474    start = utf_t::prev (start,
    475 		 text,
    476 		 &unicode,
    477 		 HB_BUFFER_REPLACEMENT_CODEPOINT_DEFAULT);
    478 
    479  return start;
    480 }
    481 
    482 
    483 #endif /* HB_UTF_HH */