From 2ec3ba46a3c24469096e901750e38f6ee555479a Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Sun, 29 Jul 2012 22:02:24 -0400
Subject: [PATCH] [GSUB/GPOS] Minor

Start squeezing more out of lig_id/lig_comp.
---
 src/hb-ot-layout-gsub-table.hh |  6 +++---
 src/hb-ot-layout-private.hh    | 35 ++++++++++++++++++++++++++++++----
 2 files changed, 34 insertions(+), 7 deletions(-)

diff --git a/src/hb-ot-layout-gsub-table.hh b/src/hb-ot-layout-gsub-table.hh
index a74f70750..2c76ae0e8 100644
--- a/src/hb-ot-layout-gsub-table.hh
+++ b/src/hb-ot-layout-gsub-table.hh
@@ -215,7 +215,7 @@ struct Sequence
     unsigned int klass = c->property & HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE ? HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH : 0;
     unsigned int count = substitute.len;
     for (unsigned int i = 0; i < count; i++) {
-      set_lig_props (c->buffer->cur(), 0, i);
+      set_lig_props_for_component (c->buffer->cur(), i);
       c->output_glyph (substitute.array[i], klass);
     }
     c->buffer->skip_glyph ();
@@ -512,7 +512,7 @@ struct Ligature
     /* Allocate new ligature id */
     unsigned int lig_id = is_a_mark_ligature ? 0 : allocate_lig_id (c->buffer);
     if (!is_a_mark_ligature)
-      set_lig_props (c->buffer->cur(), lig_id, 0);
+      set_lig_props_for_ligature (c->buffer->cur(), lig_id, count);
 
     if (skippy_iter.idx < c->buffer->idx + count) /* No input glyphs skipped */
     {
@@ -536,7 +536,7 @@ struct Ligature
 	while (c->should_mark_skip_current_glyph ())
 	{
 	  if (!is_a_mark_ligature)
-	    set_lig_props (c->buffer->cur(),  lig_id, i);
+	    set_lig_props_for_mark (c->buffer->cur(),  lig_id, i);
 	  c->buffer->next_glyph ();
 	}
 
diff --git a/src/hb-ot-layout-private.hh b/src/hb-ot-layout-private.hh
index 1c108e042..62ba8d7c4 100644
--- a/src/hb-ot-layout-private.hh
+++ b/src/hb-ot-layout-private.hh
@@ -94,17 +94,44 @@ _hb_ot_layout_skip_mark (hb_face_t    *face,
 static inline void
 set_lig_props (hb_glyph_info_t &info, unsigned int lig_id, unsigned int lig_comp)
 {
-  info.lig_props() = (lig_id << 4) | (lig_comp & 0x0F);
+  info.lig_props() = (lig_id << 5) | (lig_comp & 0x0F);
 }
+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) | 0x10 | (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() >> 4;
+  return info.lig_props() >> 5;
 }
 static inline unsigned int
 get_lig_comp (const hb_glyph_info_t &info)
 {
-  return info.lig_props() & 0x0F;
+  if (info.lig_props() & 0x10)
+    return 0;
+  else
+    return info.lig_props() & 0x0F;
+}
+static inline unsigned int
+get_lig_num_comps (const hb_glyph_info_t &info)
+{
+  if (info.lig_props() & 0x10)
+    return info.lig_props() & 0x0F;
+  else
+    return 1;
 }
 static inline bool
 is_a_ligature (const hb_glyph_info_t &info)
@@ -113,7 +140,7 @@ is_a_ligature (const hb_glyph_info_t &info)
 }
 
 static inline uint8_t allocate_lig_id (hb_buffer_t *buffer) {
-  uint8_t lig_id = buffer->next_serial () & 0x0F;
+  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;