[pango/harfbuzz-ng] Switch Pango to new, defunt, GPOS

[Behdad Esfahbod <behdad src gnome org>]

commit a483de8e2774ecf9bc281b46fdd21b4d58ed61a2
Author: Behdad Esfahbod <behdad behdad org>
Date:   Mon May 18 17:43:49 2009 -0400

    Switch Pango to new, defunt, GPOS
---
 pango/opentype/hb-ot-layout-gpos-private.h |   22 ++++--
 pango/opentype/hb-ot-layout.cc             |   13 ++++
 pango/opentype/hb-ot-layout.h              |    5 ++
 pango/pango-ot-info.c                      |   97 ++++++++++++++++++----------
 pango/pango-ot-private.h                   |    5 +-
 pango/pango-ot-ruleset.c                   |   32 +--------
 6 files changed, 102 insertions(+), 72 deletions(-)

diff --git a/pango/opentype/hb-ot-layout-gpos-private.h b/pango/opentype/hb-ot-layout-gpos-private.h
index b0b9513..056131b 100644
--- a/pango/opentype/hb-ot-layout-gpos-private.h
+++ b/pango/opentype/hb-ot-layout-gpos-private.h
@@ -843,16 +843,24 @@ struct PosLookup : Lookup {
     if (HB_UNLIKELY (!buffer->in_length))
       return false;
 
-    _hb_buffer_clear_positions (buffer);
+    layout->gpos_info.last = 0xFFFF; /* no last valid glyph for cursive pos. */
+
     buffer->in_pos = 0;
     while (buffer->in_pos < buffer->in_length) {
 
-      if ((~IN_PROPERTIES (buffer->in_pos) & mask) &&
-	  position_once (layout, buffer))
-	ret = true;
-      else
-	_hb_buffer_next_glyph (buffer);
-
+      bool done;
+      if (~IN_PROPERTIES (buffer->in_pos) & mask) {
+	  done = position_once (layout, buffer);
+	  ret |= done;
+      } else {
+          done = false;
+	  /* Contrary to properties defined in GDEF, user-defined properties
+	     will always stop a possible cursive positioning.                */
+	  layout->gpos_info.last = 0xFFFF;
+      }
+
+      if (!done)
+	buffer->in_pos++;
     }
 
     return ret;
diff --git a/pango/opentype/hb-ot-layout.cc b/pango/opentype/hb-ot-layout.cc
index 46f4555..4bb2eb5 100644
--- a/pango/opentype/hb-ot-layout.cc
+++ b/pango/opentype/hb-ot-layout.cc
@@ -531,6 +531,19 @@ hb_ot_layout_substitute_lookup (hb_ot_layout_t              *layout,
   return layout->gsub->substitute_lookup (layout, buffer, lookup_index, mask);
 }
 
+/*
+ * GPOS
+ */
+
+hb_bool_t
+hb_ot_layout_position_lookup   (hb_ot_layout_t              *layout,
+				hb_buffer_t                 *buffer,
+			        unsigned int                 lookup_index,
+				hb_ot_layout_feature_mask_t  mask)
+{
+  return layout->gpos->position_lookup (layout, buffer, lookup_index, mask);
+}
+
 
 
 /* TODO dupped, until he old code can be removed */
diff --git a/pango/opentype/hb-ot-layout.h b/pango/opentype/hb-ot-layout.h
index f6c0c44..f907b65 100644
--- a/pango/opentype/hb-ot-layout.h
+++ b/pango/opentype/hb-ot-layout.h
@@ -207,6 +207,11 @@ hb_ot_layout_substitute_lookup (hb_ot_layout_t              *layout,
 			        unsigned int                 lookup_index,
 				hb_ot_layout_feature_mask_t  mask);
 
+hb_bool_t
+hb_ot_layout_position_lookup   (hb_ot_layout_t              *layout,
+				hb_buffer_t                 *buffer,
+			        unsigned int                 lookup_index,
+				hb_ot_layout_feature_mask_t  mask);
 
 
 
diff --git a/pango/pango-ot-info.c b/pango/pango-ot-info.c
index fbd0377..cf309cc 100644
--- a/pango/pango-ot-info.c
+++ b/pango/pango-ot-info.c
@@ -32,12 +32,6 @@ static void synthesize_class_def (PangoOTInfo *info);
 
 static GObjectClass *parent_class;
 
-enum
-{
-  INFO_LOADED_GSUB = 1 << 1,
-  INFO_LOADED_GPOS = 1 << 2
-};
-
 GType
 pango_ot_info_get_type (void)
 {
@@ -83,12 +77,6 @@ pango_ot_info_finalize (GObject *object)
   if (info->layout)
     hb_ot_layout_destroy (info->layout);
 
-  if (info->gpos)
-    {
-      HB_Done_GPOS_Table (info->gpos);
-      info->gpos = NULL;
-    }
-
   parent_class->finalize (object);
 }
 
@@ -285,29 +273,6 @@ synthesize_class_def (PangoOTInfo *info)
     FT_Set_Charmap (info->face, old_charmap);
 }
 
-HB_GPOS
-pango_ot_info_get_gpos (PangoOTInfo *info)
-{
-  g_return_val_if_fail (PANGO_IS_OT_INFO (info), NULL);
-
-  if (!(info->loaded & INFO_LOADED_GPOS))
-    {
-      HB_Error error;
-
-      info->loaded |= INFO_LOADED_GPOS;
-
-      if (FT_IS_SFNT (info->face))
-	{
-	  error = HB_Load_GPOS_Table (info->face, &info->gpos, _pango_ot_info_get_layout (info));
-
-	  if (error && error != HB_Err_Not_Covered)
-	    g_warning ("Error loading GPOS table 0x%04X", error);
-	}
-    }
-
-  return info->gpos;
-}
-
 static hb_ot_layout_table_type_t
 get_hb_table_type (PangoOTTableType table_type)
 {
@@ -582,3 +547,65 @@ _pango_ot_info_substitute  (const PangoOTInfo    *info,
 	}
     }
 }
+
+void
+_pango_ot_info_position    (const PangoOTInfo    *info,
+			    const PangoOTRuleset *ruleset,
+			    PangoOTBuffer        *buffer)
+{
+  unsigned int i;
+
+  for (i = 0; i < ruleset->rules->len; i++)
+    {
+      PangoOTRule *rule = &g_array_index (ruleset->rules, PangoOTRule, i);
+      hb_ot_layout_feature_mask_t mask;
+      unsigned int lookup_count, j;
+
+      if (rule->table_type != PANGO_OT_TABLE_GPOS)
+	continue;
+
+      mask = rule->property_bit;
+      lookup_count = hb_ot_layout_feature_get_lookup_count (info->layout,
+							    HB_OT_LAYOUT_TABLE_TYPE_GSUB,
+							    rule->feature_index);
+
+      if (lookup_count)
+	_hb_buffer_clear_positions (buffer->buffer);
+
+      for (j = 0; j < lookup_count; j++)
+        {
+	  unsigned int lookup_index;
+
+	  lookup_index = hb_ot_layout_feature_get_lookup_index (info->layout,
+								HB_OT_LAYOUT_TABLE_TYPE_GSUB,
+								rule->feature_index,
+								j);
+	  hb_ot_layout_position_lookup (info->layout,
+					buffer->buffer,
+					lookup_index,
+					rule->property_bit);
+	}
+
+      if (lookup_count)
+	{
+	  HB_UInt   i, j;
+	  HB_Position positions = buffer->buffer->positions;
+
+	  /* First handle all left-to-right connections */
+	  for (j = 0; j < buffer->buffer->in_length; j++)
+	  {
+	    if (positions[j].cursive_chain > 0)
+	      positions[j].y_pos += positions[j - positions[j].cursive_chain].y_pos;
+	  }
+
+	  /* Then handle all right-to-left connections */
+	  for (i = buffer->buffer->in_length; i > 0; i--)
+	  {
+	    j = i - 1;
+
+	    if (positions[j].cursive_chain < 0)
+	      positions[j].y_pos += positions[j - positions[j].cursive_chain].y_pos;
+	  }
+	}
+    }
+}
diff --git a/pango/pango-ot-private.h b/pango/pango-ot-private.h
index c1ee455..ba67e26 100644
--- a/pango/pango-ot-private.h
+++ b/pango/pango-ot-private.h
@@ -40,7 +40,6 @@ struct _PangoOTInfo
   FT_Face face;
 
   hb_ot_layout_t *layout;
-  HB_GPOS gpos;
 };
 
 struct _PangoOTInfoClass
@@ -92,7 +91,9 @@ hb_ot_layout_t *_pango_ot_info_get_layout (PangoOTInfo *info);
 void _pango_ot_info_substitute  (const PangoOTInfo    *info,
 				 const PangoOTRuleset *ruleset,
 				 PangoOTBuffer        *buffer);
-HB_GPOS pango_ot_info_get_gpos (PangoOTInfo *info);
+void _pango_ot_info_position    (const PangoOTInfo    *info,
+				 const PangoOTRuleset *ruleset,
+				 PangoOTBuffer        *buffer);
 
 G_END_DECLS
 
diff --git a/pango/pango-ot-ruleset.c b/pango/pango-ot-ruleset.c
index 23f37cb..b5e2795 100644
--- a/pango/pango-ot-ruleset.c
+++ b/pango/pango-ot-ruleset.c
@@ -504,39 +504,15 @@ void
 pango_ot_ruleset_position (const PangoOTRuleset *ruleset,
 			   PangoOTBuffer        *buffer)
 {
-  unsigned int i;
-
-  HB_GPOS gpos = NULL;
-
   g_return_if_fail (PANGO_IS_OT_RULESET (ruleset));
   g_return_if_fail (ruleset->info != NULL);
 
-  for (i = 0; i < ruleset->rules->len; i++)
-    {
-      PangoOTRule *rule = &g_array_index (ruleset->rules, PangoOTRule, i);
-
-      if (rule->table_type != PANGO_OT_TABLE_GPOS)
-	continue;
-
-      if (!gpos)
-	{
-	  gpos = pango_ot_info_get_gpos (ruleset->info);
-
-	  if (gpos)
-	    HB_GPOS_Clear_Features (gpos);
-	  else
-	    return;
-	}
-
-      HB_GPOS_Add_Feature (gpos, rule->feature_index, rule->property_bit);
-    }
-
-  if (HB_GPOS_Apply_String (ruleset->info->face, gpos, 0, buffer->buffer,
-			    FALSE /* enable device-dependant values */,
-			    buffer->rtl) == HB_Err_Ok)
-    buffer->applied_gpos = TRUE;
+  _pango_ot_info_position   (ruleset->info,
+			     ruleset,
+			     buffer);
 }
 
+
 /* ruleset descriptions */
 
 /**