From bfffe85dd7d7557e10ec9f9886b86fe0d8b4a7a2 Mon Sep 17 00:00:00 2001
From: Ebrahim Byagowi <ebrahim@gnu.org>
Date: Wed, 14 Aug 2019 13:55:49 +0430
Subject: [PATCH] [opbd] Use multiformat convention on the table

---
 src/hb-aat-layout-opbd-table.hh | 116 ++++++++++++++++++++++++--------
 1 file changed, 89 insertions(+), 27 deletions(-)

diff --git a/src/hb-aat-layout-opbd-table.hh b/src/hb-aat-layout-opbd-table.hh
index 80ed1034..4e023407 100644
--- a/src/hb-aat-layout-opbd-table.hh
+++ b/src/hb-aat-layout-opbd-table.hh
@@ -53,42 +53,104 @@ struct OpticalBounds
   DEFINE_SIZE_STATIC (8);
 };
 
-struct opbd
+struct opbdFormat0
 {
-  static constexpr hb_tag_t tableTag = HB_AAT_TAG_opbd;
+  bool get_bounds (hb_font_t *font, hb_codepoint_t glyph_id,
+		   hb_glyph_extents_t *extents, const void *base) const
+  {
+    const OffsetTo<OpticalBounds> *bounds_offset = lookupTable.get_value (glyph_id, font->face->get_num_glyphs ());
+    if (!bounds_offset) return false;
+    const OpticalBounds &bounds = base+*bounds_offset;
+
+    if (extents)
+      *extents = {
+	font->em_scale_x (bounds.leftSide),
+	font->em_scale_y (bounds.topSide),
+	font->em_scale_x (bounds.rightSide),
+	font->em_scale_y (bounds.bottomSide)
+      };
+    return true;
+  }
+
+  bool sanitize (hb_sanitize_context_t *c, const void *base) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (likely (c->check_struct (this) && lookupTable.sanitize (c, base)));
+  }
+
+  protected:
+  Lookup<OffsetTo<OpticalBounds>>
+		lookupTable;	/* Lookup table associating glyphs with the four
+				 * int16 values for the left-side, top-side,
+				 * right-side, and bottom-side optical bounds. */
+  public:
+  DEFINE_SIZE_MIN (2);
+};
 
-  bool get_optical_bounds (hb_font_t *font, hb_codepoint_t glyph_id,
-			   hb_position_t *left, hb_position_t *top,
-			   hb_position_t *right, hb_position_t *bottom) const
+struct opbdFormat1
+{
+  bool get_bounds (hb_font_t *font, hb_codepoint_t glyph_id,
+		   hb_glyph_extents_t *extents, const void *base) const
   {
     const OffsetTo<OpticalBounds> *bounds_offset = lookupTable.get_value (glyph_id, font->face->get_num_glyphs ());
     if (!bounds_offset) return false;
-    const OpticalBounds &bounds = this+*bounds_offset;
-    switch (format)
+    const OpticalBounds &bounds = base+*bounds_offset;
+
+    hb_position_t left = 0, top = 0, right = 0, bottom = 0, ignore;
+    if (font->get_glyph_contour_point (glyph_id, bounds.leftSide, &left, &ignore) ||
+	font->get_glyph_contour_point (glyph_id, bounds.topSide, &ignore, &top) ||
+	font->get_glyph_contour_point (glyph_id, bounds.rightSide, &right, &ignore) ||
+	font->get_glyph_contour_point (glyph_id, bounds.bottomSide, &ignore, &bottom))
     {
-    case 0:
-      *left = font->em_scale_x (bounds.leftSide);
-      *top = font->em_scale_y (bounds.topSide);
-      *right = font->em_scale_x (bounds.rightSide);
-      *bottom = font->em_scale_y (bounds.bottomSide);
+      if (extents)
+	*extents = {left, top, right, bottom};
       return true;
-    case 1:
-      hb_position_t ignore;
-      return font->get_glyph_contour_point (glyph_id, bounds.leftSide, left, &ignore) &&
-	     font->get_glyph_contour_point (glyph_id, bounds.topSide, &ignore, top) &&
-	     font->get_glyph_contour_point (glyph_id, bounds.rightSide, right, &ignore) &&
-	     font->get_glyph_contour_point (glyph_id, bounds.bottomSide, &ignore, bottom);
-    default:
-      return false;
+    }
+    return false;
+  }
+
+  bool sanitize (hb_sanitize_context_t *c, const void *base) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (likely (c->check_struct (this) && lookupTable.sanitize (c, base)));
+  }
+
+  protected:
+  Lookup<OffsetTo<OpticalBounds>>
+		lookupTable;	/* Lookup table associating glyphs with the four
+				 * int16 values for the left-side, top-side,
+				 * right-side, and bottom-side optical bounds. */
+  public:
+  DEFINE_SIZE_MIN (2);
+};
+
+struct opbd
+{
+  static constexpr hb_tag_t tableTag = HB_AAT_TAG_opbd;
+
+  bool get_bounds (hb_font_t *font, hb_codepoint_t glyph_id,
+		   hb_glyph_extents_t *extents) const
+  {
+    switch (format)
+    {
+    case 0: return u.format0.get_bounds (font, glyph_id, extents, this);
+    case 1: return u.format1.get_bounds (font, glyph_id, extents, this);
+    default:return false;
     }
   }
 
   bool sanitize (hb_sanitize_context_t *c) const
   {
     TRACE_SANITIZE (this);
-    return_trace (likely (c->check_struct (this) &&
-			  version.major == 1 &&
-			  lookupTable.sanitize (c, this)));
+    if (unlikely (!c->check_struct (this) || version.major != 1))
+      return_trace (false);
+
+    switch (format)
+    {
+    case 0: return_trace (u.format0.sanitize (c, this));
+    case 1: return_trace (u.format1.sanitize (c, this));
+    default:return_trace (true);
+    }
   }
 
   protected:
@@ -97,10 +159,10 @@ struct opbd
   HBUINT16	format;		/* Format of the optical bounds table.
 				 * Format 0 indicates distance and Format 1 indicates
 				 * control point. */
-  Lookup<OffsetTo<OpticalBounds>>
-		lookupTable;	/* Lookup table associating glyphs with the four
-				 * int16 values for the left-side, top-side,
-				 * right-side, and bottom-side optical bounds. */
+  union {
+  opbdFormat0 format0;
+  opbdFormat1 format1;
+  } u;
   public:
   DEFINE_SIZE_MIN (8);
 };
-- 
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