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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