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1 /*
2  * Copyright © 2007,2008,2009  Red Hat, Inc.
3  * Copyright © 2012  Google, Inc.
4  *
5  *  This is part of HarfBuzz, a text shaping library.
6  *
7  * Permission is hereby granted, without written agreement and without
8  * license or royalty fees, to use, copy, modify, and distribute this
9  * software and its documentation for any purpose, provided that the
10  * above copyright notice and the following two paragraphs appear in
11  * all copies of this software.
12  *
13  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
14  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
15  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
16  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
17  * DAMAGE.
18  *
19  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
20  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
21  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
22  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
23  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
24  *
25  * Red Hat Author(s): Behdad Esfahbod
26  * Google Author(s): Behdad Esfahbod
27  */
28 
29 #ifndef HB_OT_LAYOUT_PRIVATE_HH
30 #define HB_OT_LAYOUT_PRIVATE_HH
31 
32 #include "hb-private.hh"
33 
34 #include "hb-ot-layout.h"
35 
36 #include "hb-font-private.hh"
37 #include "hb-buffer-private.hh"
38 #include "hb-set-private.hh"
39 
40 
41 /* buffer var allocations, used during the GSUB/GPOS processing */
42 #define glyph_props()		var1.u16[0] /* GDEF glyph properties */
43 #define syllable()		var1.u8[2] /* GSUB/GPOS shaping boundaries */
44 #define lig_props()		var1.u8[3] /* GSUB/GPOS ligature tracking */
45 
46 /* buffer var allocations, used during the entire shaping process */
47 #define unicode_props0()	var2.u8[0]
48 #define unicode_props1()	var2.u8[1]
49 
50 
51 inline void
_hb_glyph_info_set_unicode_props(hb_glyph_info_t * info,hb_unicode_funcs_t * unicode)52 _hb_glyph_info_set_unicode_props (hb_glyph_info_t *info, hb_unicode_funcs_t *unicode)
53 {
54   info->unicode_props0() = ((unsigned int) unicode->general_category (info->codepoint)) |
55 			   (unicode->is_default_ignorable (info->codepoint) ? 0x80 : 0) |
56 			   (info->codepoint == 0x200C ? 0x40 : 0) |
57 			   (info->codepoint == 0x200D ? 0x20 : 0);
58   info->unicode_props1() = unicode->modified_combining_class (info->codepoint);
59 }
60 
61 inline hb_unicode_general_category_t
_hb_glyph_info_get_general_category(const hb_glyph_info_t * info)62 _hb_glyph_info_get_general_category (const hb_glyph_info_t *info)
63 {
64   return (hb_unicode_general_category_t) (info->unicode_props0() & 0x1F);
65 }
66 
67 inline void
_hb_glyph_info_set_modified_combining_class(hb_glyph_info_t * info,unsigned int modified_class)68 _hb_glyph_info_set_modified_combining_class (hb_glyph_info_t *info, unsigned int modified_class)
69 {
70   info->unicode_props1() = modified_class;
71 }
72 
73 inline unsigned int
_hb_glyph_info_get_modified_combining_class(const hb_glyph_info_t * info)74 _hb_glyph_info_get_modified_combining_class (const hb_glyph_info_t *info)
75 {
76   return info->unicode_props1();
77 }
78 
79 inline hb_bool_t
_hb_glyph_info_is_default_ignorable(const hb_glyph_info_t * info)80 _hb_glyph_info_is_default_ignorable (const hb_glyph_info_t *info)
81 {
82   return !!(info->unicode_props0() & 0x80);
83 }
84 
85 inline hb_bool_t
_hb_glyph_info_is_zwnj(const hb_glyph_info_t * info)86 _hb_glyph_info_is_zwnj (const hb_glyph_info_t *info)
87 {
88   return !!(info->unicode_props0() & 0x40);
89 }
90 
91 inline hb_bool_t
_hb_glyph_info_is_zwj(const hb_glyph_info_t * info)92 _hb_glyph_info_is_zwj (const hb_glyph_info_t *info)
93 {
94   return !!(info->unicode_props0() & 0x20);
95 }
96 
97 
98 #define hb_ot_layout_from_face(face) ((hb_ot_layout_t *) face->shaper_data.ot)
99 
100 /*
101  * GDEF
102  */
103 
104 typedef enum {
105   HB_OT_LAYOUT_GLYPH_PROPS_UNCLASSIFIED	= 1 << HB_OT_LAYOUT_GLYPH_CLASS_UNCLASSIFIED,
106   HB_OT_LAYOUT_GLYPH_PROPS_BASE_GLYPH	= 1 << HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH,
107   HB_OT_LAYOUT_GLYPH_PROPS_LIGATURE	= 1 << HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE,
108   HB_OT_LAYOUT_GLYPH_PROPS_MARK		= 1 << HB_OT_LAYOUT_GLYPH_CLASS_MARK,
109   HB_OT_LAYOUT_GLYPH_PROPS_COMPONENT	= 1 << HB_OT_LAYOUT_GLYPH_CLASS_COMPONENT
110 } hb_ot_layout_glyph_class_mask_t;
111 
112 
113 
114 /*
115  * GSUB/GPOS
116  */
117 
118 /* lig_id / lig_comp
119  *
120  * When a ligature is formed:
121  *
122  *   - The ligature glyph and any marks in between all the same newly allocated
123  *     lig_id,
124  *   - The ligature glyph will get lig_num_comps set to the number of components
125  *   - The marks get lig_comp > 0, reflecting which component of the ligature
126  *     they were applied to.
127  *   - This is used in GPOS to attach marks to the right component of a ligature
128  *     in MarkLigPos.
129  *
130  * When a multiple-substitution is done:
131  *
132  *   - All resulting glyphs will have lig_id = 0,
133  *   - The resulting glyphs will have lig_comp = 0, 1, 2, ... respectively.
134  *   - This is used in GPOS to attach marks to the first component of a
135  *     multiple substitution in MarkBasePos.
136  *
137  * The numbers are also used in GPOS to do mark-to-mark positioning only
138  * to marks that belong to the same component of a ligature in MarkMarPos.
139  */
140 #define IS_LIG_BASE 0x10
141 static inline void
set_lig_props_for_ligature(hb_glyph_info_t & info,unsigned int lig_id,unsigned int lig_num_comps)142 set_lig_props_for_ligature (hb_glyph_info_t &info, unsigned int lig_id, unsigned int lig_num_comps)
143 {
144   info.lig_props() = (lig_id << 5) | IS_LIG_BASE | (lig_num_comps & 0x0F);
145 }
146 static inline void
set_lig_props_for_mark(hb_glyph_info_t & info,unsigned int lig_id,unsigned int lig_comp)147 set_lig_props_for_mark (hb_glyph_info_t &info, unsigned int lig_id, unsigned int lig_comp)
148 {
149   info.lig_props() = (lig_id << 5) | (lig_comp & 0x0F);
150 }
151 static inline void
set_lig_props_for_component(hb_glyph_info_t & info,unsigned int comp)152 set_lig_props_for_component (hb_glyph_info_t &info, unsigned int comp)
153 {
154   set_lig_props_for_mark (info, 0, comp);
155 }
156 
157 static inline unsigned int
get_lig_id(const hb_glyph_info_t & info)158 get_lig_id (const hb_glyph_info_t &info)
159 {
160   return info.lig_props() >> 5;
161 }
162 static inline bool
is_a_ligature(const hb_glyph_info_t & info)163 is_a_ligature (const hb_glyph_info_t &info)
164 {
165   return !!(info.lig_props() & IS_LIG_BASE);
166 }
167 static inline unsigned int
get_lig_comp(const hb_glyph_info_t & info)168 get_lig_comp (const hb_glyph_info_t &info)
169 {
170   if (is_a_ligature (info))
171     return 0;
172   else
173     return info.lig_props() & 0x0F;
174 }
175 static inline unsigned int
get_lig_num_comps(const hb_glyph_info_t & info)176 get_lig_num_comps (const hb_glyph_info_t &info)
177 {
178   if ((info.glyph_props() & HB_OT_LAYOUT_GLYPH_PROPS_LIGATURE) && is_a_ligature (info))
179     return info.lig_props() & 0x0F;
180   else
181     return 1;
182 }
183 
allocate_lig_id(hb_buffer_t * buffer)184 static inline uint8_t allocate_lig_id (hb_buffer_t *buffer) {
185   uint8_t lig_id = buffer->next_serial () & 0x07;
186   if (unlikely (!lig_id))
187     lig_id = allocate_lig_id (buffer); /* in case of overflow */
188   return lig_id;
189 }
190 
191 
192 HB_INTERNAL hb_bool_t
193 hb_ot_layout_lookup_would_substitute_fast (hb_face_t            *face,
194 					   unsigned int          lookup_index,
195 					   const hb_codepoint_t *glyphs,
196 					   unsigned int          glyphs_length,
197 					   hb_bool_t             zero_context);
198 
199 
200 /* Should be called before all the substitute_lookup's are done. */
201 HB_INTERNAL void
202 hb_ot_layout_substitute_start (hb_font_t    *font,
203 			       hb_buffer_t  *buffer);
204 
205 HB_INTERNAL hb_bool_t
206 hb_ot_layout_substitute_lookup (hb_font_t    *font,
207 				hb_buffer_t  *buffer,
208 				unsigned int  lookup_index,
209 				hb_mask_t     mask,
210 				hb_bool_t     auto_zwj);
211 
212 /* Should be called after all the substitute_lookup's are done */
213 HB_INTERNAL void
214 hb_ot_layout_substitute_finish (hb_font_t    *font,
215 				hb_buffer_t  *buffer);
216 
217 
218 /* Should be called before all the position_lookup's are done.  Resets positions to zero. */
219 HB_INTERNAL void
220 hb_ot_layout_position_start (hb_font_t    *font,
221 			     hb_buffer_t  *buffer);
222 
223 HB_INTERNAL hb_bool_t
224 hb_ot_layout_position_lookup (hb_font_t    *font,
225 			      hb_buffer_t  *buffer,
226 			      unsigned int  lookup_index,
227 			      hb_mask_t     mask,
228 			      hb_bool_t     auto_zwj);
229 
230 /* Should be called after all the position_lookup's are done */
231 HB_INTERNAL void
232 hb_ot_layout_position_finish (hb_font_t    *font,
233 			      hb_buffer_t  *buffer);
234 
235 
236 
237 /*
238  * hb_ot_layout_t
239  */
240 
241 namespace OT {
242   struct GDEF;
243   struct GSUB;
244   struct GPOS;
245 }
246 
247 struct hb_ot_layout_t
248 {
249   hb_blob_t *gdef_blob;
250   hb_blob_t *gsub_blob;
251   hb_blob_t *gpos_blob;
252 
253   const struct OT::GDEF *gdef;
254   const struct OT::GSUB *gsub;
255   const struct OT::GPOS *gpos;
256 
257   unsigned int gsub_lookup_count;
258   unsigned int gpos_lookup_count;
259 
260   hb_set_digest_t *gsub_digests;
261   hb_set_digest_t *gpos_digests;
262 };
263 
264 
265 HB_INTERNAL hb_ot_layout_t *
266 _hb_ot_layout_create (hb_face_t *face);
267 
268 HB_INTERNAL void
269 _hb_ot_layout_destroy (hb_ot_layout_t *layout);
270 
271 
272 
273 #endif /* HB_OT_LAYOUT_PRIVATE_HH */
274