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_PRIVATE_HH
31 #define HB_BUFFER_PRIVATE_HH
32 
33 #include "hb-private.hh"
34 #include "hb-object-private.hh"
35 #include "hb-unicode-private.hh"
36 
37 
38 #ifndef HB_BUFFER_MAX_EXPANSION_FACTOR
39 #define HB_BUFFER_MAX_EXPANSION_FACTOR 32
40 #endif
41 #ifndef HB_BUFFER_MAX_LEN_MIN
42 #define HB_BUFFER_MAX_LEN_MIN 8192
43 #endif
44 #ifndef HB_BUFFER_MAX_LEN_DEFAULT
45 #define HB_BUFFER_MAX_LEN_DEFAULT 0x3FFFFFFF /* Shaping more than a billion chars? Let us know! */
46 #endif
47 
48 ASSERT_STATIC (sizeof (hb_glyph_info_t) == 20);
49 ASSERT_STATIC (sizeof (hb_glyph_info_t) == sizeof (hb_glyph_position_t));
50 
51 HB_MARK_AS_FLAG_T (hb_buffer_flags_t);
52 HB_MARK_AS_FLAG_T (hb_buffer_serialize_flags_t);
53 
54 enum hb_buffer_scratch_flags_t {
55   HB_BUFFER_SCRATCH_FLAG_DEFAULT			= 0x00000000u,
56   HB_BUFFER_SCRATCH_FLAG_HAS_NON_ASCII			= 0x00000001u,
57   HB_BUFFER_SCRATCH_FLAG_HAS_DEFAULT_IGNORABLES		= 0x00000002u,
58   HB_BUFFER_SCRATCH_FLAG_HAS_SPACE_FALLBACK		= 0x00000004u,
59   HB_BUFFER_SCRATCH_FLAG_HAS_GPOS_ATTACHMENT		= 0x00000008u,
60   /* Reserved for complex shapers' internal use. */
61   HB_BUFFER_SCRATCH_FLAG_COMPLEX0			= 0x01000000u,
62   HB_BUFFER_SCRATCH_FLAG_COMPLEX1			= 0x02000000u,
63   HB_BUFFER_SCRATCH_FLAG_COMPLEX2			= 0x04000000u,
64   HB_BUFFER_SCRATCH_FLAG_COMPLEX3			= 0x08000000u,
65 };
66 HB_MARK_AS_FLAG_T (hb_buffer_scratch_flags_t);
67 
68 
69 /*
70  * hb_buffer_t
71  */
72 
73 struct hb_buffer_t {
74   hb_object_header_t header;
75   ASSERT_POD ();
76 
77   /* Information about how the text in the buffer should be treated */
78   hb_unicode_funcs_t *unicode; /* Unicode functions */
79   hb_buffer_flags_t flags; /* BOT / EOT / etc. */
80   hb_buffer_cluster_level_t cluster_level;
81   hb_codepoint_t replacement; /* U+FFFD or something else. */
82   hb_buffer_scratch_flags_t scratch_flags; /* Have space-flallback, etc. */
83   unsigned int max_len; /* Maximum allowed len. */
84 
85   /* Buffer contents */
86   hb_buffer_content_type_t content_type;
87   hb_segment_properties_t props; /* Script, language, direction */
88 
89   bool in_error; /* Allocation failed */
90   bool have_output; /* Whether we have an output buffer going on */
91   bool have_positions; /* Whether we have positions */
92 
93   unsigned int idx; /* Cursor into ->info and ->pos arrays */
94   unsigned int len; /* Length of ->info and ->pos arrays */
95   unsigned int out_len; /* Length of ->out array if have_output */
96 
97   unsigned int allocated; /* Length of allocated arrays */
98   hb_glyph_info_t     *info;
99   hb_glyph_info_t     *out_info;
100   hb_glyph_position_t *pos;
101 
curhb_buffer_t102   inline hb_glyph_info_t &cur (unsigned int i = 0) { return info[idx + i]; }
curhb_buffer_t103   inline hb_glyph_info_t cur (unsigned int i = 0) const { return info[idx + i]; }
104 
cur_poshb_buffer_t105   inline hb_glyph_position_t &cur_pos (unsigned int i = 0) { return pos[idx + i]; }
cur_poshb_buffer_t106   inline hb_glyph_position_t cur_pos (unsigned int i = 0) const { return pos[idx + i]; }
107 
prevhb_buffer_t108   inline hb_glyph_info_t &prev (void) { return out_info[out_len ? out_len - 1 : 0]; }
prevhb_buffer_t109   inline hb_glyph_info_t prev (void) const { return out_info[out_len ? out_len - 1 : 0]; }
110 
has_separate_outputhb_buffer_t111   inline bool has_separate_output (void) const { return info != out_info; }
112 
113   unsigned int serial;
114 
115   /* Text before / after the main buffer contents.
116    * Always in Unicode, and ordered outward.
117    * Index 0 is for "pre-context", 1 for "post-context". */
118   static const unsigned int CONTEXT_LENGTH = 5;
119   hb_codepoint_t context[2][CONTEXT_LENGTH];
120   unsigned int context_len[2];
121 
122   /* Debugging API */
123   hb_buffer_message_func_t message_func;
124   void *message_data;
125   hb_destroy_func_t message_destroy;
126 
127   /* Internal debugging. */
128   /* The bits here reflect current allocations of the bytes in glyph_info_t's var1 and var2. */
129 #ifndef HB_NDEBUG
130   uint8_t allocated_var_bits;
131 #endif
allocate_varhb_buffer_t132   inline void allocate_var (unsigned int start, unsigned int count)
133   {
134 #ifndef HB_NDEBUG
135     unsigned int end = start + count;
136     assert (end <= 8);
137     unsigned int bits = (1<<end) - (1<<start);
138     assert (0 == (allocated_var_bits & bits));
139     allocated_var_bits |= bits;
140 #endif
141   }
deallocate_varhb_buffer_t142   inline void deallocate_var (unsigned int start, unsigned int count)
143   {
144 #ifndef HB_NDEBUG
145     unsigned int end = start + count;
146     assert (end <= 8);
147     unsigned int bits = (1<<end) - (1<<start);
148     assert (bits == (allocated_var_bits & bits));
149     allocated_var_bits &= ~bits;
150 #endif
151   }
assert_varhb_buffer_t152   inline void assert_var (unsigned int start, unsigned int count)
153   {
154 #ifndef HB_NDEBUG
155     unsigned int end = start + count;
156     assert (end <= 8);
157     unsigned int bits = (1<<end) - (1<<start);
158     assert (bits == (allocated_var_bits & bits));
159 #endif
160   }
deallocate_var_allhb_buffer_t161   inline void deallocate_var_all (void)
162   {
163 #ifndef HB_NDEBUG
164     allocated_var_bits = 0;
165 #endif
166   }
167 
168 
169   /* Methods */
170 
171   HB_INTERNAL void reset (void);
172   HB_INTERNAL void clear (void);
173 
backtrack_lenhb_buffer_t174   inline unsigned int backtrack_len (void) const
175   { return have_output? out_len : idx; }
lookahead_lenhb_buffer_t176   inline unsigned int lookahead_len (void) const
177   { return len - idx; }
next_serialhb_buffer_t178   inline unsigned int next_serial (void) { return serial++; }
179 
180   HB_INTERNAL void add (hb_codepoint_t  codepoint,
181 			unsigned int    cluster);
182   HB_INTERNAL void add_info (const hb_glyph_info_t &glyph_info);
183 
184   HB_INTERNAL void reverse_range (unsigned int start, unsigned int end);
185   HB_INTERNAL void reverse (void);
186   HB_INTERNAL void reverse_clusters (void);
187   HB_INTERNAL void guess_segment_properties (void);
188 
189   HB_INTERNAL void swap_buffers (void);
190   HB_INTERNAL void remove_output (void);
191   HB_INTERNAL void clear_output (void);
192   HB_INTERNAL void clear_positions (void);
193 
194   HB_INTERNAL void replace_glyphs (unsigned int num_in,
195 				   unsigned int num_out,
196 				   const hb_codepoint_t *glyph_data);
197 
198   HB_INTERNAL void replace_glyph (hb_codepoint_t glyph_index);
199   /* Makes a copy of the glyph at idx to output and replace glyph_index */
200   HB_INTERNAL void output_glyph (hb_codepoint_t glyph_index);
201   HB_INTERNAL void output_info (const hb_glyph_info_t &glyph_info);
202   /* Copies glyph at idx to output but doesn't advance idx */
203   HB_INTERNAL void copy_glyph (void);
204   HB_INTERNAL bool move_to (unsigned int i); /* i is output-buffer index. */
205   /* Copies glyph at idx to output and advance idx.
206    * If there's no output, just advance idx. */
207   inline void
next_glyphhb_buffer_t208   next_glyph (void)
209   {
210     if (have_output)
211     {
212       if (unlikely (out_info != info || out_len != idx)) {
213 	if (unlikely (!make_room_for (1, 1))) return;
214 	out_info[out_len] = info[idx];
215       }
216       out_len++;
217     }
218 
219     idx++;
220   }
221 
222   /* Advance idx without copying to output. */
skip_glyphhb_buffer_t223   inline void skip_glyph (void) { idx++; }
224 
reset_maskshb_buffer_t225   inline void reset_masks (hb_mask_t mask)
226   {
227     for (unsigned int j = 0; j < len; j++)
228       info[j].mask = mask;
229   }
add_maskshb_buffer_t230   inline void add_masks (hb_mask_t mask)
231   {
232     for (unsigned int j = 0; j < len; j++)
233       info[j].mask |= mask;
234   }
235   HB_INTERNAL void set_masks (hb_mask_t value,
236 			      hb_mask_t mask,
237 			      unsigned int cluster_start,
238 			      unsigned int cluster_end);
239 
merge_clustershb_buffer_t240   HB_INTERNAL void merge_clusters (unsigned int start,
241 				   unsigned int end)
242   {
243     if (end - start < 2)
244       return;
245     merge_clusters_impl (start, end);
246   }
247   HB_INTERNAL void merge_clusters_impl (unsigned int start,
248 					unsigned int end);
249   HB_INTERNAL void merge_out_clusters (unsigned int start,
250 				       unsigned int end);
251   /* Merge clusters for deleting current glyph, and skip it. */
252   HB_INTERNAL void delete_glyph (void);
253 
254   /* Internal methods */
255   HB_INTERNAL bool enlarge (unsigned int size);
256 
ensurehb_buffer_t257   inline bool ensure (unsigned int size)
258   { return likely (!size || size < allocated) ? true : enlarge (size); }
259 
ensure_inplacehb_buffer_t260   inline bool ensure_inplace (unsigned int size)
261   { return likely (!size || size < allocated); }
262 
263   HB_INTERNAL bool make_room_for (unsigned int num_in, unsigned int num_out);
264   HB_INTERNAL bool shift_forward (unsigned int count);
265 
266   typedef long scratch_buffer_t;
267   HB_INTERNAL scratch_buffer_t *get_scratch_buffer (unsigned int *size);
268 
clear_contexthb_buffer_t269   inline void clear_context (unsigned int side) { context_len[side] = 0; }
270 
271   HB_INTERNAL void sort (unsigned int start, unsigned int end, int(*compar)(const hb_glyph_info_t *, const hb_glyph_info_t *));
272 
messaginghb_buffer_t273   inline bool messaging (void) { return unlikely (message_func); }
messagehb_buffer_t274   inline bool message (hb_font_t *font, const char *fmt, ...) HB_PRINTF_FUNC(3, 4)
275   {
276     if (!messaging ())
277       return true;
278     va_list ap;
279     va_start (ap, fmt);
280     bool ret = message_impl (font, fmt, ap);
281     va_end (ap);
282     return ret;
283   }
284   HB_INTERNAL bool message_impl (hb_font_t *font, const char *fmt, va_list ap) HB_PRINTF_FUNC(3, 0);
285 };
286 
287 
288 #define HB_BUFFER_XALLOCATE_VAR(b, func, var) \
289   b->func (offsetof (hb_glyph_info_t, var) - offsetof(hb_glyph_info_t, var1), \
290 	   sizeof (b->info[0].var))
291 #define HB_BUFFER_ALLOCATE_VAR(b, var)		HB_BUFFER_XALLOCATE_VAR (b, allocate_var,   var ())
292 #define HB_BUFFER_DEALLOCATE_VAR(b, var)	HB_BUFFER_XALLOCATE_VAR (b, deallocate_var, var ())
293 #define HB_BUFFER_ASSERT_VAR(b, var)		HB_BUFFER_XALLOCATE_VAR (b, assert_var,     var ())
294 
295 
296 #endif /* HB_BUFFER_PRIVATE_HH */
297