Formalize buffer var allocations

src/hb-buffer-private.hh

@@ -84,26 +84,10 @@ struct _hb_buffer_t {
   { return have_output? out_len : idx; }
   inline unsigned int next_serial (void) { return serial++; }
 
-
   HB_INTERNAL void allocate_var (unsigned int byte_i, unsigned int count, const char *owner);
   HB_INTERNAL void deallocate_var (unsigned int byte_i, unsigned int count, const char *owner);
   HB_INTERNAL void deallocate_var_all (void);
 
-  inline void allocate_var_8 (unsigned int var_num, unsigned int i, const char *owner)
-  { assert (var_num < 2 && i < 4); allocate_var (var_num * 4 + i, 1, owner); }
-  inline void allocate_var_16 (unsigned int var_num, unsigned int i, const char *owner)
-  { assert (var_num < 2 && i < 2); allocate_var (var_num * 4 + i * 2, 2, owner); }
-  inline void allocate_var_32 (unsigned int var_num, const char *owner)
-  { assert (var_num < 2); allocate_var (var_num * 4, 4, owner); }
-
-  inline void deallocate_var_8 (unsigned int var_num, unsigned int i, const char *owner)
-  { assert (var_num < 2 && i < 4); deallocate_var (var_num * 4 + i, 1, owner); }
-  inline void deallocate_var_16 (unsigned int var_num, unsigned int i, const char *owner)
-  { assert (var_num < 2 && i < 2); deallocate_var (var_num * 4 + i * 2, 2, owner); }
-  inline void deallocate_var_32 (unsigned int var_num, const char *owner)
-  { assert (var_num < 2); deallocate_var (var_num * 4, 4, owner); }
-
-
   HB_INTERNAL void add (hb_codepoint_t  codepoint,
 			hb_mask_t       mask,
 			unsigned int    cluster);
@@ -154,6 +138,15 @@ struct _hb_buffer_t {
 };
 
 
+#define HB_BUFFER_XALLOCATE_VAR(b, func, var, owner) \
+  b->func (offsetof (hb_glyph_info_t, var) - offsetof(hb_glyph_info_t, var1), \
+	   sizeof (b->info[0].var), owner)
+#define HB_BUFFER_ALLOCATE_VAR(b, var) \
+	HB_BUFFER_XALLOCATE_VAR (b, allocate_var, var (), #var)
+#define HB_BUFFER_DEALLOCATE_VAR(b, var) \
+	HB_BUFFER_XALLOCATE_VAR (b, deallocate_var, var (), #var)
+
+
 HB_END_DECLS
 
 #endif /* HB_BUFFER_PRIVATE_HH */

src/hb-buffer.cc

@@ -398,7 +398,7 @@ dump_var_allocation (const hb_buffer_t *buffer)
 {
   char buf[80];
   for (unsigned int i = 0; i < 8; i++)
-    buf[i] = '0' + buffer->allocated_var_bytes[i];
+    buf[i] = '0' + buffer->allocated_var_bytes[7 - i];
   buf[8] = '\0';
   DEBUG_MSG (BUFFER, buffer,
 	     "Current var allocation: %s",
@@ -407,7 +407,7 @@ dump_var_allocation (const hb_buffer_t *buffer)
 
 void hb_buffer_t::allocate_var (unsigned int byte_i, unsigned int count, const char *owner)
 {
-  assert (byte_i < 8 && byte_i + count < 8);
+  assert (byte_i < 8 && byte_i + count <= 8);
 
   if (DEBUG (BUFFER))
     dump_var_allocation (this);
@@ -424,18 +424,19 @@ void hb_buffer_t::allocate_var (unsigned int byte_i, unsigned int count, const c
 
 void hb_buffer_t::deallocate_var (unsigned int byte_i, unsigned int count, const char *owner)
 {
+  if (DEBUG (BUFFER))
+    dump_var_allocation (this);
+
   DEBUG_MSG (BUFFER, this,
 	     "Deallocating var bytes %d..%d for %s",
 	     byte_i, byte_i + count - 1, owner);
 
-  assert (byte_i < 8 && byte_i + count < 8);
+  assert (byte_i < 8 && byte_i + count <= 8);
   for (unsigned int i = byte_i; i < byte_i + count; i++) {
-    assert (allocated_var_bytes[i] && allocated_var_owner[i] == owner);
+    assert (allocated_var_bytes[i]);
+    assert (0 == strcmp (allocated_var_owner[i], owner));
     allocated_var_bytes[i]--;
   }
-
-  if (DEBUG (BUFFER))
-    dump_var_allocation (this);
 }
 
 void hb_buffer_t::deallocate_var_all (void)

src/hb-ot-layout-gpos-private.hh

@@ -34,7 +34,7 @@
 HB_BEGIN_DECLS
 
 
-/* buffer var allocations */
+/* buffer **position** var allocations */
 #define attach_lookback() var.u16[0] /* number of glyphs to go back to attach this glyph to its base */
 #define cursive_chain() var.i16[1] /* character to which this connects, may be positive or negative */
 
@@ -1569,6 +1569,10 @@ void
 GPOS::position_start (hb_buffer_t *buffer)
 {
   buffer->clear_positions ();
+
+  unsigned int count = buffer->len;
+  for (unsigned int i = 0; i < count; i++)
+    buffer->pos[i].attach_lookback() = buffer->pos[i].cursive_chain() = 0;
 }
 
 void
@@ -1580,15 +1584,15 @@ GPOS::position_finish (hb_buffer_t *buffer)
 
   /* Handle cursive connections */
   for (unsigned int i = 0; i < len; i++)
-  {
     fix_cursive_minor_offset (pos, i, direction);
-  }
 
   /* Handle attachments */
   for (unsigned int i = 0; i < len; i++)
-  {
     fix_mark_attachment (pos, i, direction);
-  }
+
+  HB_BUFFER_DEALLOCATE_VAR (buffer, lig_comp);
+  HB_BUFFER_DEALLOCATE_VAR (buffer, lig_id);
+  HB_BUFFER_DEALLOCATE_VAR (buffer, props_cache);
 }
 
 

src/hb-ot-layout-gsub-private.hh

@@ -887,8 +887,11 @@ struct GSUB : GSUBGPOS
 void
 GSUB::substitute_start (hb_buffer_t *buffer)
 {
+  HB_BUFFER_ALLOCATE_VAR (buffer, props_cache);
+  HB_BUFFER_ALLOCATE_VAR (buffer, lig_id);
+  HB_BUFFER_ALLOCATE_VAR (buffer, lig_comp);
+
   unsigned int count = buffer->len;
-  /* XXX */
   for (unsigned int i = 0; i < count; i++)
     buffer->info[i].var1.u32 = buffer->info[i].var2.u32 = 0;
 }

src/hb-ot-shape-complex-arabic.cc

@@ -30,7 +30,7 @@ HB_BEGIN_DECLS
 
 
 /* buffer var allocations */
-#define arabic_shaping_action() var2.u32 /* arabic shaping action */
+#define arabic_shaping_action() complex_var_temporary_u16() /* arabic shaping action */
 
 
 /*
@@ -195,6 +195,8 @@ _hb_ot_shape_complex_setup_masks_arabic (hb_ot_map_t *map, hb_buffer_t *buffer)
   unsigned int count = buffer->len;
   unsigned int prev = 0, state = 0;
 
+  HB_BUFFER_ALLOCATE_VAR (buffer, arabic_shaping_action);
+
   for (unsigned int i = 0; i < count; i++)
   {
     unsigned int this_type = get_joining_type (buffer->info[i].codepoint, (hb_unicode_general_category_t) buffer->info[i].general_category());
@@ -222,6 +224,8 @@ _hb_ot_shape_complex_setup_masks_arabic (hb_ot_map_t *map, hb_buffer_t *buffer)
 
   for (unsigned int i = 0; i < count; i++)
     buffer->info[i].mask |= mask_array[buffer->info[i].arabic_shaping_action()];
+
+  HB_BUFFER_DEALLOCATE_VAR (buffer, arabic_shaping_action);
 }
 
 

src/hb-ot-shape-complex-indic.cc

@@ -30,8 +30,8 @@ HB_BEGIN_DECLS
 
 
 /* buffer var allocations */
-#define indic_category() var2.u8[0] /* indic_category_t */
+#define indic_category() complex_var_persistent_u8_0() /* indic_category_t */
-#define indic_position() var2.u8[1] /* indic_matra_category_t */
+#define indic_position() complex_var_persistent_u8_1() /* indic_matra_category_t */
 
 #define INDIC_TABLE_ELEMENT_TYPE uint8_t
 

src/hb-ot-shape-complex-private.hh

@@ -34,10 +34,18 @@
 HB_BEGIN_DECLS
 
 
-/* buffer var allocations, used by all shapers */
+/* buffer var allocations, used during the entire shaping process */
 #define general_category() var1.u8[0] /* unicode general_category (hb_unicode_general_category_t) */
 #define combining_class() var1.u8[1] /* unicode combining_class (uint8_t) */
 
+/* buffer var allocations, used by complex shapers */
+#define complex_var_persistent_u8_0()	var2.u8[0]
+#define complex_var_persistent_u8_1()	var2.u8[1]
+#define complex_var_persistent_u16()	var2.u16[0]
+#define complex_var_temporary_u8_0()	var2.u8[2]
+#define complex_var_temporary_u8_1()	var2.u8[3]
+#define complex_var_temporary_u16()	var2.u16[1]
+
 
 #define HB_COMPLEX_SHAPERS_IMPLEMENT_SHAPERS \
   HB_COMPLEX_SHAPER_IMPLEMENT (default) /* should be first */ \

src/hb-ot-shape.cc

@@ -115,7 +115,7 @@ hb_ot_shape_setup_masks (hb_ot_shape_context_t *c)
   hb_mask_t global_mask = c->plan->map.get_global_mask ();
   c->buffer->reset_masks (global_mask);
 
-  hb_ot_shape_complex_setup_masks (c->plan->shaper, &c->plan->map, c->buffer); /* BUFFER: Clobbers var2 */
+  hb_ot_shape_complex_setup_masks (c->plan->shaper, &c->plan->map, c->buffer);
 
   for (unsigned int i = 0; i < c->num_user_features; i++)
   {
@@ -225,16 +225,20 @@ hb_map_glyphs (hb_font_t    *font,
 static void
 hb_substitute_default (hb_ot_shape_context_t *c)
 {
+  hb_ot_layout_substitute_start (c->buffer);
+
+  hb_mirror_chars (c);
+
   hb_map_glyphs (c->font, c->buffer);
 }
 
 static void
 hb_ot_substitute_complex (hb_ot_shape_context_t *c)
 {
-  if (!hb_ot_layout_has_substitution (c->face))
+  if (hb_ot_layout_has_substitution (c->face))
-    return;
+    c->plan->map.substitute (c->face, c->buffer);
 
-  c->plan->map.substitute (c->face, c->buffer);
+  hb_ot_layout_substitute_finish (c->buffer);
 
   c->applied_substitute_complex = TRUE;
   return;
@@ -271,24 +275,26 @@ static void
 hb_ot_position_complex (hb_ot_shape_context_t *c)
 {
 
-  if (!hb_ot_layout_has_positioning (c->face))
+  if (hb_ot_layout_has_positioning (c->face))
-    return;
+  {
+    /* Change glyph origin to what GPOS expects, apply GPOS, change it back. */
 
-  unsigned int count = c->buffer->len;
+    unsigned int count = c->buffer->len;
-  for (unsigned int i = 0; i < count; i++) {
+    for (unsigned int i = 0; i < count; i++) {
-    hb_font_add_glyph_origin_for_direction (c->font, c->buffer->info[i].codepoint,
+      hb_font_add_glyph_origin_for_direction (c->font, c->buffer->info[i].codepoint,
-					    HB_DIRECTION_LTR,
+					      HB_DIRECTION_LTR,
-					    &c->buffer->pos[i].x_offset,
+					      &c->buffer->pos[i].x_offset,
-					    &c->buffer->pos[i].y_offset);
+					      &c->buffer->pos[i].y_offset);
-  }
+    }
 
-  c->plan->map.position (c->font, c->buffer);
+    c->plan->map.position (c->font, c->buffer);
 
-  for (unsigned int i = 0; i < count; i++) {
+    for (unsigned int i = 0; i < count; i++) {
-    hb_font_subtract_glyph_origin_for_direction (c->font, c->buffer->info[i].codepoint,
+      hb_font_subtract_glyph_origin_for_direction (c->font, c->buffer->info[i].codepoint,
-						 HB_DIRECTION_LTR,
+						   HB_DIRECTION_LTR,
-						 &c->buffer->pos[i].x_offset,
+						   &c->buffer->pos[i].x_offset,
-						 &c->buffer->pos[i].y_offset);
+						   &c->buffer->pos[i].y_offset);
+    }
   }
 
   hb_ot_layout_position_finish (c->buffer);
@@ -341,10 +347,15 @@ hb_position_complex_fallback_visual (hb_ot_shape_context_t *c)
 static void
 hb_ot_shape_execute_internal (hb_ot_shape_context_t *c)
 {
+  c->buffer->deallocate_var_all ();
+
   /* Save the original direction, we use it later. */
   c->target_direction = c->buffer->props.direction;
 
-  _hb_set_unicode_props (c->buffer); /* BUFFER: Set general_category and combining_class in var1 */
+  HB_BUFFER_ALLOCATE_VAR (c->buffer, general_category);
+  HB_BUFFER_ALLOCATE_VAR (c->buffer, combining_class);
+
+  _hb_set_unicode_props (c->buffer); /* BUFFER: Set general_category and combining_class */
 
   hb_form_clusters (c->buffer);
 
@@ -352,12 +363,10 @@ hb_ot_shape_execute_internal (hb_ot_shape_context_t *c)
 
   _hb_ot_shape_normalize (c);
 
-  hb_ot_shape_setup_masks (c); /* BUFFER: Clobbers var2 */
+  hb_ot_shape_setup_masks (c);
 
   /* SUBSTITUTE */
   {
-    hb_mirror_chars (c);
-
     hb_substitute_default (c);
 
     hb_ot_substitute_complex (c);
@@ -383,6 +392,9 @@ hb_ot_shape_execute_internal (hb_ot_shape_context_t *c)
       hb_position_complex_fallback_visual (c);
   }
 
+  HB_BUFFER_DEALLOCATE_VAR (c->buffer, combining_class);
+  HB_BUFFER_DEALLOCATE_VAR (c->buffer, general_category);
+
   c->buffer->props.direction = c->target_direction;
 }
 

src/hb-private.hh

@@ -36,6 +36,7 @@
 #include "hb-common.h"
 
 #include <stdlib.h>
+#include <stddef.h>
 #include <string.h>
 #include <assert.h>