harfbuzz-ng roll

third_party/harfbuzz-ng/src/hb-ot-layout-private.hh

 /*
  * Copyright © 2007,2008,2009  Red Hat, Inc.
+ * Copyright © 2012  Google, Inc.
  *
  *  This is part of HarfBuzz, a text shaping library.
  *
  * Permission is hereby granted, without written agreement and without
  * license or royalty fees, to use, copy, modify, and distribute this
  * software and its documentation for any purpose, provided that the
  * above copyright notice and the following two paragraphs appear in
  * all copies of this software.
  *
  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
  * DAMAGE.
  *
  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  *
  * Red Hat Author(s): Behdad Esfahbod
+ * Google Author(s): Behdad Esfahbod
  */
 
 #ifndef HB_OT_LAYOUT_PRIVATE_HH
 #define HB_OT_LAYOUT_PRIVATE_HH
 
 #include "hb-private.hh"
 
 #include "hb-ot-layout.h"
 
 #include "hb-font-private.hh"
 #include "hb-buffer-private.hh"
-#include "hb-ot-shape-complex-private.hh"
+#include "hb-set-private.hh"
 
 
+/* buffer var allocations, used during the GSUB/GPOS processing */
+#define glyph_props()           var1.u16[0] /* GDEF glyph properties */
+#define syllable()              var1.u8[2] /* GSUB/GPOS shaping boundaries */
+#define lig_props()             var1.u8[3] /* GSUB/GPOS ligature tracking */
+
+#define hb_ot_layout_from_face(face) ((hb_ot_layout_t *) face->shaper_data.ot)
 
 /*
  * GDEF
  */
 
-/* XXX cleanup */
 typedef enum {
   HB_OT_LAYOUT_GLYPH_CLASS_UNCLASSIFIED = 0x0001,
   HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH   = 0x0002,
   HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE     = 0x0004,
   HB_OT_LAYOUT_GLYPH_CLASS_MARK         = 0x0008,
   HB_OT_LAYOUT_GLYPH_CLASS_COMPONENT    = 0x0010
 } hb_ot_layout_glyph_class_t;
 
 
-HB_INTERNAL unsigned int
-_hb_ot_layout_get_glyph_property (hb_face_t       *face,
-                                  hb_glyph_info_t *info);
+
+/*
+ * GSUB/GPOS
+ */
+
+/* lig_id / lig_comp
+ *
+ * When a ligature is formed:
+ *
+ *   - The ligature glyph and any marks in between all the same newly allocated
+ *     lig_id,
+ *   - The ligature glyph will get lig_num_comps set to the number of components
+ *   - The marks get lig_comp > 0, reflecting which component of the ligature
+ *     they were applied to.
+ *   - This is used in GPOS to attach marks to the right component of a ligature
+ *     in MarkLigPos.
+ *
+ * When a multiple-substitution is done:
+ *
+ *   - All resulting glyphs will have lig_id = 0,
+ *   - The resulting glyphs will have lig_comp = 0, 1, 2, ... respectively.
+ *   - This is used in GPOS to attach marks to the first component of a
+ *     multiple substitution in MarkBasePos.
+ *
+ * The numbers are also used in GPOS to do mark-to-mark positioning only
+ * to marks that belong to the same component of a ligature in MarkMarPos.
+ */
+#define IS_LIG_BASE 0x10
+static inline void
+set_lig_props_for_ligature (hb_glyph_info_t &info, unsigned int lig_id, unsigned int lig_num_comps)
+{
+  info.lig_props() = (lig_id << 5) | IS_LIG_BASE | (lig_num_comps & 0x0F);
+}
+static inline void
+set_lig_props_for_mark (hb_glyph_info_t &info, unsigned int lig_id, unsigned int lig_comp)
+{
+  info.lig_props() = (lig_id << 5) | (lig_comp & 0x0F);
+}
+static inline void
+set_lig_props_for_component (hb_glyph_info_t &info, unsigned int comp)
+{
+  set_lig_props_for_mark (info, 0, comp);
+}
+
+static inline unsigned int
+get_lig_id (const hb_glyph_info_t &info)
+{
+  return info.lig_props() >> 5;
+}
+static inline bool
+is_a_ligature (const hb_glyph_info_t &info)
+{
+  return !!(info.lig_props() & IS_LIG_BASE);
+}
+static inline unsigned int
+get_lig_comp (const hb_glyph_info_t &info)
+{
+  if (is_a_ligature (info))
+    return 0;
+  else
+    return info.lig_props() & 0x0F;
+}
+static inline unsigned int
+get_lig_num_comps (const hb_glyph_info_t &info)
+{
+  if ((info.glyph_props() & HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE) && is_a_ligature (info))
+    return info.lig_props() & 0x0F;
+  else
+    return 1;
+}
+
+static inline uint8_t allocate_lig_id (hb_buffer_t *buffer) {
+  uint8_t lig_id = buffer->next_serial () & 0x07;
+  if (unlikely (!lig_id))
+    lig_id = allocate_lig_id (buffer); /* in case of overflow */
+  return lig_id;
+}
+
 
 HB_INTERNAL hb_bool_t
-_hb_ot_layout_check_glyph_property (hb_face_t    *face,
-                                    hb_glyph_info_t *ginfo,
-                                    unsigned int  lookup_props,
-                                    unsigned int *property_out);
+hb_ot_layout_would_substitute_lookup_fast (hb_face_t            *face,
+                                           unsigned int          lookup_index,
+                                           const hb_codepoint_t *glyphs,
+                                           unsigned int          glyphs_length,
+                                           hb_bool_t             zero_context);
+
+
+/* Should be called before all the substitute_lookup's are done. */
+HB_INTERNAL void
+hb_ot_layout_substitute_start (hb_font_t    *font,
+                               hb_buffer_t  *buffer);
 
 HB_INTERNAL hb_bool_t
-_hb_ot_layout_skip_mark (hb_face_t    *face,
-                         hb_glyph_info_t *ginfo,
-                         unsigned int  lookup_props,
-                         unsigned int *property_out);
+hb_ot_layout_substitute_lookup (hb_font_t    *font,
+                                hb_buffer_t  *buffer,
+                                unsigned int  lookup_index,
+                                hb_mask_t     mask);
+
+/* Should be called after all the substitute_lookup's are done */
+HB_INTERNAL void
+hb_ot_layout_substitute_finish (hb_font_t    *font,
+                                hb_buffer_t  *buffer);
+
+
+/* Should be called before all the position_lookup's are done.  Resets positions to zero. */
+HB_INTERNAL void
+hb_ot_layout_position_start (hb_font_t    *font,
+                             hb_buffer_t  *buffer);
+
+HB_INTERNAL hb_bool_t
+hb_ot_layout_position_lookup (hb_font_t    *font,
+                              hb_buffer_t  *buffer,
+                              unsigned int  lookup_index,
+                              hb_mask_t     mask);
+
+/* Should be called after all the position_lookup's are done */
+HB_INTERNAL void
+hb_ot_layout_position_finish (hb_font_t    *font,
+                              hb_buffer_t  *buffer,
+                              hb_bool_t     zero_width_attached_marks);
 
 
 
 /*
  * hb_ot_layout_t
  */
 
+namespace OT {
+  struct GDEF;
+  struct GSUB;
+  struct GPOS;
+}
+
 struct hb_ot_layout_t
 {
   hb_blob_t *gdef_blob;
   hb_blob_t *gsub_blob;
   hb_blob_t *gpos_blob;
 
-  const struct GDEF *gdef;
-  const struct GSUB *gsub;
-  const struct GPOS *gpos;
+  const struct OT::GDEF *gdef;
+  const struct OT::GSUB *gsub;
+  const struct OT::GPOS *gpos;
+
+  unsigned int gsub_lookup_count;
+  unsigned int gpos_lookup_count;
+
+  hb_set_digest_t *gsub_digests;
+  hb_set_digest_t *gpos_digests;
 };
 
 
 HB_INTERNAL hb_ot_layout_t *
 _hb_ot_layout_create (hb_face_t *face);
 
 HB_INTERNAL void
 _hb_ot_layout_destroy (hb_ot_layout_t *layout);
 
 
 
 #endif /* HB_OT_LAYOUT_PRIVATE_HH */