• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1  /*
2   * Copyright © 1998-2004  David Turner and Werner Lemberg
3   * Copyright © 2004,2007,2009,2010  Red Hat, Inc.
4   * Copyright © 2011,2012  Google, Inc.
5   *
6   *  This is part of HarfBuzz, a text shaping library.
7   *
8   * Permission is hereby granted, without written agreement and without
9   * license or royalty fees, to use, copy, modify, and distribute this
10   * software and its documentation for any purpose, provided that the
11   * above copyright notice and the following two paragraphs appear in
12   * all copies of this software.
13   *
14   * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
15   * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
16   * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
17   * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
18   * DAMAGE.
19   *
20   * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
21   * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
22   * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
23   * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
24   * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
25   *
26   * Red Hat Author(s): Owen Taylor, Behdad Esfahbod
27   * Google Author(s): Behdad Esfahbod
28   */
29  
30  #ifndef HB_BUFFER_HH
31  #define HB_BUFFER_HH
32  
33  #include "hb.hh"
34  #include "hb-unicode.hh"
35  
36  
37  #ifndef HB_BUFFER_MAX_LEN_FACTOR
38  #define HB_BUFFER_MAX_LEN_FACTOR 32
39  #endif
40  #ifndef HB_BUFFER_MAX_LEN_MIN
41  #define HB_BUFFER_MAX_LEN_MIN 8192
42  #endif
43  #ifndef HB_BUFFER_MAX_LEN_DEFAULT
44  #define HB_BUFFER_MAX_LEN_DEFAULT 0x3FFFFFFF /* Shaping more than a billion chars? Let us know! */
45  #endif
46  
47  #ifndef HB_BUFFER_MAX_OPS_FACTOR
48  #define HB_BUFFER_MAX_OPS_FACTOR 64
49  #endif
50  #ifndef HB_BUFFER_MAX_OPS_MIN
51  #define HB_BUFFER_MAX_OPS_MIN 1024
52  #endif
53  #ifndef HB_BUFFER_MAX_OPS_DEFAULT
54  #define HB_BUFFER_MAX_OPS_DEFAULT 0x1FFFFFFF /* Shaping more than a billion operations? Let us know! */
55  #endif
56  
57  static_assert ((sizeof (hb_glyph_info_t) == 20), "");
58  static_assert ((sizeof (hb_glyph_info_t) == sizeof (hb_glyph_position_t)), "");
59  
60  HB_MARK_AS_FLAG_T (hb_buffer_flags_t);
61  HB_MARK_AS_FLAG_T (hb_buffer_serialize_flags_t);
62  HB_MARK_AS_FLAG_T (hb_buffer_diff_flags_t);
63  
64  enum hb_buffer_scratch_flags_t {
65    HB_BUFFER_SCRATCH_FLAG_DEFAULT			= 0x00000000u,
66    HB_BUFFER_SCRATCH_FLAG_HAS_NON_ASCII			= 0x00000001u,
67    HB_BUFFER_SCRATCH_FLAG_HAS_DEFAULT_IGNORABLES		= 0x00000002u,
68    HB_BUFFER_SCRATCH_FLAG_HAS_SPACE_FALLBACK		= 0x00000004u,
69    HB_BUFFER_SCRATCH_FLAG_HAS_GPOS_ATTACHMENT		= 0x00000008u,
70    HB_BUFFER_SCRATCH_FLAG_HAS_UNSAFE_TO_BREAK		= 0x00000010u,
71    HB_BUFFER_SCRATCH_FLAG_HAS_CGJ			= 0x00000020u,
72  
73    /* Reserved for complex shapers' internal use. */
74    HB_BUFFER_SCRATCH_FLAG_COMPLEX0			= 0x01000000u,
75    HB_BUFFER_SCRATCH_FLAG_COMPLEX1			= 0x02000000u,
76    HB_BUFFER_SCRATCH_FLAG_COMPLEX2			= 0x04000000u,
77    HB_BUFFER_SCRATCH_FLAG_COMPLEX3			= 0x08000000u,
78  };
79  HB_MARK_AS_FLAG_T (hb_buffer_scratch_flags_t);
80  
81  
82  /*
83   * hb_buffer_t
84   */
85  
86  struct hb_buffer_t
87  {
88    hb_object_header_t header;
89  
90    /* Information about how the text in the buffer should be treated */
91    hb_unicode_funcs_t *unicode; /* Unicode functions */
92    hb_buffer_flags_t flags; /* BOT / EOT / etc. */
93    hb_buffer_cluster_level_t cluster_level;
94    hb_codepoint_t replacement; /* U+FFFD or something else. */
95    hb_codepoint_t invisible; /* 0 or something else. */
96    hb_buffer_scratch_flags_t scratch_flags; /* Have space-fallback, etc. */
97    unsigned int max_len; /* Maximum allowed len. */
98    int max_ops; /* Maximum allowed operations. */
99  
100    /* Buffer contents */
101    hb_buffer_content_type_t content_type;
102    hb_segment_properties_t props; /* Script, language, direction */
103  
104    bool successful; /* Allocations successful */
105    bool have_output; /* Whether we have an output buffer going on */
106    bool have_positions; /* Whether we have positions */
107  
108    unsigned int idx; /* Cursor into ->info and ->pos arrays */
109    unsigned int len; /* Length of ->info and ->pos arrays */
110    unsigned int out_len; /* Length of ->out array if have_output */
111  
112    unsigned int allocated; /* Length of allocated arrays */
113    hb_glyph_info_t     *info;
114    hb_glyph_info_t     *out_info;
115    hb_glyph_position_t *pos;
116  
117    unsigned int serial;
118  
119    /* Text before / after the main buffer contents.
120     * Always in Unicode, and ordered outward.
121     * Index 0 is for "pre-context", 1 for "post-context". */
122    static constexpr unsigned CONTEXT_LENGTH = 5u;
123    hb_codepoint_t context[2][CONTEXT_LENGTH];
124    unsigned int context_len[2];
125  
126    /* Debugging API */
127  #ifndef HB_NO_BUFFER_MESSAGE
128    hb_buffer_message_func_t message_func;
129    void *message_data;
130    hb_destroy_func_t message_destroy;
131  #endif
132  
133    /* Internal debugging. */
134    /* The bits here reflect current allocations of the bytes in glyph_info_t's var1 and var2. */
135  #ifndef HB_NDEBUG
136    uint8_t allocated_var_bits;
137  #endif
138  
139  
140    /* Methods */
141  
in_errorhb_buffer_t142    bool in_error () const { return !successful; }
143  
allocate_varhb_buffer_t144    void allocate_var (unsigned int start, unsigned int count)
145    {
146  #ifndef HB_NDEBUG
147      unsigned int end = start + count;
148      assert (end <= 8);
149      unsigned int bits = (1u<<end) - (1u<<start);
150      assert (0 == (allocated_var_bits & bits));
151      allocated_var_bits |= bits;
152  #endif
153    }
deallocate_varhb_buffer_t154    void deallocate_var (unsigned int start, unsigned int count)
155    {
156  #ifndef HB_NDEBUG
157      unsigned int end = start + count;
158      assert (end <= 8);
159      unsigned int bits = (1u<<end) - (1u<<start);
160      assert (bits == (allocated_var_bits & bits));
161      allocated_var_bits &= ~bits;
162  #endif
163    }
assert_varhb_buffer_t164    void assert_var (unsigned int start, unsigned int count)
165    {
166  #ifndef HB_NDEBUG
167      unsigned int end = start + count;
168      assert (end <= 8);
169      unsigned int bits = (1u<<end) - (1u<<start);
170      assert (bits == (allocated_var_bits & bits));
171  #endif
172    }
deallocate_var_allhb_buffer_t173    void deallocate_var_all ()
174    {
175  #ifndef HB_NDEBUG
176      allocated_var_bits = 0;
177  #endif
178    }
179  
curhb_buffer_t180    hb_glyph_info_t &cur (unsigned int i = 0) { return info[idx + i]; }
curhb_buffer_t181    hb_glyph_info_t cur (unsigned int i = 0) const { return info[idx + i]; }
182  
cur_poshb_buffer_t183    hb_glyph_position_t &cur_pos (unsigned int i = 0) { return pos[idx + i]; }
cur_poshb_buffer_t184    hb_glyph_position_t cur_pos (unsigned int i = 0) const { return pos[idx + i]; }
185  
prevhb_buffer_t186    hb_glyph_info_t &prev ()      { return out_info[out_len ? out_len - 1 : 0]; }
prevhb_buffer_t187    hb_glyph_info_t prev () const { return out_info[out_len ? out_len - 1 : 0]; }
188  
has_separate_outputhb_buffer_t189    bool has_separate_output () const { return info != out_info; }
190  
191  
192    HB_INTERNAL void reset ();
193    HB_INTERNAL void clear ();
194  
backtrack_lenhb_buffer_t195    unsigned int backtrack_len () const { return have_output? out_len : idx; }
lookahead_lenhb_buffer_t196    unsigned int lookahead_len () const { return len - idx; }
next_serialhb_buffer_t197    unsigned int next_serial () { return serial++; }
198  
199    HB_INTERNAL void add (hb_codepoint_t  codepoint,
200  			unsigned int    cluster);
201    HB_INTERNAL void add_info (const hb_glyph_info_t &glyph_info);
202  
203    HB_INTERNAL void reverse_range (unsigned int start, unsigned int end);
204    HB_INTERNAL void reverse ();
205    HB_INTERNAL void reverse_clusters ();
206    HB_INTERNAL void guess_segment_properties ();
207  
208    HB_INTERNAL void swap_buffers ();
209    HB_INTERNAL void remove_output ();
210    HB_INTERNAL void clear_output ();
211    HB_INTERNAL void clear_positions ();
212  
213    HB_INTERNAL void replace_glyphs (unsigned int num_in,
214  				   unsigned int num_out,
215  				   const hb_codepoint_t *glyph_data);
216  
replace_glyphhb_buffer_t217    void replace_glyph (hb_codepoint_t glyph_index)
218    {
219      if (unlikely (out_info != info || out_len != idx)) {
220        if (unlikely (!make_room_for (1, 1))) return;
221        out_info[out_len] = info[idx];
222      }
223      out_info[out_len].codepoint = glyph_index;
224  
225      idx++;
226      out_len++;
227    }
228    /* Makes a copy of the glyph at idx to output and replace glyph_index */
output_glyphhb_buffer_t229    hb_glyph_info_t & output_glyph (hb_codepoint_t glyph_index)
230    {
231      if (unlikely (!make_room_for (0, 1))) return Crap(hb_glyph_info_t);
232  
233      if (unlikely (idx == len && !out_len))
234        return Crap(hb_glyph_info_t);
235  
236      out_info[out_len] = idx < len ? info[idx] : out_info[out_len - 1];
237      out_info[out_len].codepoint = glyph_index;
238  
239      out_len++;
240  
241      return out_info[out_len - 1];
242    }
output_infohb_buffer_t243    void output_info (const hb_glyph_info_t &glyph_info)
244    {
245      if (unlikely (!make_room_for (0, 1))) return;
246  
247      out_info[out_len] = glyph_info;
248  
249      out_len++;
250    }
251    /* Copies glyph at idx to output but doesn't advance idx */
copy_glyphhb_buffer_t252    void copy_glyph ()
253    {
254      if (unlikely (!make_room_for (0, 1))) return;
255  
256      out_info[out_len] = info[idx];
257  
258      out_len++;
259    }
260    /* Copies glyph at idx to output and advance idx.
261     * If there's no output, just advance idx. */
262    void
next_glyphhb_buffer_t263    next_glyph ()
264    {
265      if (have_output)
266      {
267        if (out_info != info || out_len != idx)
268        {
269  	if (unlikely (!make_room_for (1, 1))) return;
270  	out_info[out_len] = info[idx];
271        }
272        out_len++;
273      }
274  
275      idx++;
276    }
277    /* Copies n glyphs at idx to output and advance idx.
278     * If there's no output, just advance idx. */
279    void
next_glyphshb_buffer_t280    next_glyphs (unsigned int n)
281    {
282      if (have_output)
283      {
284        if (out_info != info || out_len != idx)
285        {
286  	if (unlikely (!make_room_for (n, n))) return;
287  	memmove (out_info + out_len, info + idx, n * sizeof (out_info[0]));
288        }
289        out_len += n;
290      }
291  
292      idx += n;
293    }
294    /* Advance idx without copying to output. */
skip_glyphhb_buffer_t295    void skip_glyph () { idx++; }
reset_maskshb_buffer_t296    void reset_masks (hb_mask_t mask)
297    {
298      for (unsigned int j = 0; j < len; j++)
299        info[j].mask = mask;
300    }
add_maskshb_buffer_t301    void add_masks (hb_mask_t mask)
302    {
303      for (unsigned int j = 0; j < len; j++)
304        info[j].mask |= mask;
305    }
306    HB_INTERNAL void set_masks (hb_mask_t value, hb_mask_t mask,
307  			      unsigned int cluster_start, unsigned int cluster_end);
308  
merge_clustershb_buffer_t309    void merge_clusters (unsigned int start, unsigned int end)
310    {
311      if (end - start < 2)
312        return;
313      merge_clusters_impl (start, end);
314    }
315    HB_INTERNAL void merge_clusters_impl (unsigned int start, unsigned int end);
316    HB_INTERNAL void merge_out_clusters (unsigned int start, unsigned int end);
317    /* Merge clusters for deleting current glyph, and skip it. */
318    HB_INTERNAL void delete_glyph ();
319  
unsafe_to_breakhb_buffer_t320    void unsafe_to_break (unsigned int start,
321  			       unsigned int end)
322    {
323      if (end - start < 2)
324        return;
325      unsafe_to_break_impl (start, end);
326    }
327    HB_INTERNAL void unsafe_to_break_impl (unsigned int start, unsigned int end);
328    HB_INTERNAL void unsafe_to_break_from_outbuffer (unsigned int start, unsigned int end);
329  
330  
331    /* Internal methods */
332    HB_INTERNAL bool move_to (unsigned int i); /* i is output-buffer index. */
333  
334    HB_INTERNAL bool enlarge (unsigned int size);
335  
ensurehb_buffer_t336    bool ensure (unsigned int size)
337    { return likely (!size || size < allocated) ? true : enlarge (size); }
338  
ensure_inplacehb_buffer_t339    bool ensure_inplace (unsigned int size)
340    { return likely (!size || size < allocated); }
341  
342    HB_INTERNAL bool make_room_for (unsigned int num_in, unsigned int num_out);
343    HB_INTERNAL bool shift_forward (unsigned int count);
344  
345    typedef long scratch_buffer_t;
346    HB_INTERNAL scratch_buffer_t *get_scratch_buffer (unsigned int *size);
347  
clear_contexthb_buffer_t348    void clear_context (unsigned int side) { context_len[side] = 0; }
349  
350    HB_INTERNAL void sort (unsigned int start, unsigned int end, int(*compar)(const hb_glyph_info_t *, const hb_glyph_info_t *));
351  
messaginghb_buffer_t352    bool messaging ()
353    {
354  #ifdef HB_NO_BUFFER_MESSAGE
355      return false;
356  #else
357      return unlikely (message_func);
358  #endif
359    }
messagehb_buffer_t360    bool message (hb_font_t *font, const char *fmt, ...) HB_PRINTF_FUNC(3, 4)
361    {
362  #ifdef HB_NO_BUFFER_MESSAGE
363     return true;
364  #else
365      if (!messaging ())
366        return true;
367      va_list ap;
368      va_start (ap, fmt);
369      bool ret = message_impl (font, fmt, ap);
370      va_end (ap);
371      return ret;
372  #endif
373    }
374    HB_INTERNAL bool message_impl (hb_font_t *font, const char *fmt, va_list ap) HB_PRINTF_FUNC(3, 0);
375  
376    static void
set_clusterhb_buffer_t377    set_cluster (hb_glyph_info_t &inf, unsigned int cluster, unsigned int mask = 0)
378    {
379      if (inf.cluster != cluster)
380      {
381        if (mask & HB_GLYPH_FLAG_UNSAFE_TO_BREAK)
382  	inf.mask |= HB_GLYPH_FLAG_UNSAFE_TO_BREAK;
383        else
384  	inf.mask &= ~HB_GLYPH_FLAG_UNSAFE_TO_BREAK;
385      }
386      inf.cluster = cluster;
387    }
388  
389    int
_unsafe_to_break_find_min_clusterhb_buffer_t390    _unsafe_to_break_find_min_cluster (const hb_glyph_info_t *infos,
391  				     unsigned int start, unsigned int end,
392  				     unsigned int cluster) const
393    {
394      for (unsigned int i = start; i < end; i++)
395        cluster = hb_min (cluster, infos[i].cluster);
396      return cluster;
397    }
398    void
_unsafe_to_break_set_maskhb_buffer_t399    _unsafe_to_break_set_mask (hb_glyph_info_t *infos,
400  			     unsigned int start, unsigned int end,
401  			     unsigned int cluster)
402    {
403      for (unsigned int i = start; i < end; i++)
404        if (cluster != infos[i].cluster)
405        {
406  	scratch_flags |= HB_BUFFER_SCRATCH_FLAG_HAS_UNSAFE_TO_BREAK;
407  	infos[i].mask |= HB_GLYPH_FLAG_UNSAFE_TO_BREAK;
408        }
409    }
410  
unsafe_to_break_allhb_buffer_t411    void unsafe_to_break_all () { unsafe_to_break_impl (0, len); }
safe_to_break_allhb_buffer_t412    void safe_to_break_all ()
413    {
414      for (unsigned int i = 0; i < len; i++)
415        info[i].mask &= ~HB_GLYPH_FLAG_UNSAFE_TO_BREAK;
416    }
417  };
418  DECLARE_NULL_INSTANCE (hb_buffer_t);
419  
420  
421  /* Loop over clusters. Duplicated in foreach_syllable(). */
422  #define foreach_cluster(buffer, start, end) \
423    for (unsigned int \
424         _count = buffer->len, \
425         start = 0, end = _count ? _next_cluster (buffer, 0) : 0; \
426         start < _count; \
427         start = end, end = _next_cluster (buffer, start))
428  
429  static inline unsigned int
_next_cluster(hb_buffer_t * buffer,unsigned int start)430  _next_cluster (hb_buffer_t *buffer, unsigned int start)
431  {
432    hb_glyph_info_t *info = buffer->info;
433    unsigned int count = buffer->len;
434  
435    unsigned int cluster = info[start].cluster;
436    while (++start < count && cluster == info[start].cluster)
437      ;
438  
439    return start;
440  }
441  
442  
443  #define HB_BUFFER_XALLOCATE_VAR(b, func, var) \
444    b->func (offsetof (hb_glyph_info_t, var) - offsetof(hb_glyph_info_t, var1), \
445  	   sizeof (b->info[0].var))
446  #define HB_BUFFER_ALLOCATE_VAR(b, var)		HB_BUFFER_XALLOCATE_VAR (b, allocate_var,   var ())
447  #define HB_BUFFER_DEALLOCATE_VAR(b, var)	HB_BUFFER_XALLOCATE_VAR (b, deallocate_var, var ())
448  #define HB_BUFFER_ASSERT_VAR(b, var)		HB_BUFFER_XALLOCATE_VAR (b, assert_var,     var ())
449  
450  
451  #endif /* HB_BUFFER_HH */
452