[subset] Dinner time, checkpoint

src/hb-ot-glyf-table.hh

@@ -86,9 +86,13 @@ struct glyf
   {
     TRACE_SERIALIZE (this);
 
-    // TODO actually copy glyph
-    // TODO worry about instructions
-    // TODO capture dest locations for loca
+    // pad glyphs to 2-byte boundaries to permit short loca
+    HBUINT8 pad;
+    + it
+    | hb_apply ( [&] (hb_bytes_t glyph) {
+      glyph.copy(c);
+      if (glyph.length % 2) c->extend(pad);
+    });
 
     return_trace (true);
   }
@@ -103,32 +107,54 @@ struct glyf
     OT::glyf::accelerator_t glyf;
     glyf.init (c->plan->source);
 
-    // stream new-gids => pair of start/end offsets
-    // can now copy glyph from <prev>=>end
-    // TODO(instructions)
+    // stream new-gids => glyph to keep
+    // if dropping hints the glyph to keep doesn't have them anymore
     auto it =
     + hb_iota (c->plan->num_output_glyphs ())
     | hb_map ([&] (hb_codepoint_t new_gid) {
-      unsigned int start_offset = 0, end_offset = 0;
-
       hb_codepoint_t old_gid;
-      // should never happen, ALL old gids should be mapped
-      if (!c->plan->old_gid_for_new_gid (new_gid, &old_gid)) return hb_pair (start_offset, end_offset);
-
-      // being empty is perfectly normal
-      if (c->plan->is_empty_glyph (old_gid)) return hb_pair (start_offset, end_offset);
+      // should never happen fail, ALL old gids should be mapped
+      if (!c->plan->old_gid_for_new_gid (new_gid, &old_gid)) return hb_bytes_t ();
 
+      unsigned int start_offset, end_offset;
       if (unlikely (!(glyf.get_offsets (old_gid, &start_offset, &end_offset) &&
 	glyf.remove_padding (start_offset, &end_offset))))
       {
 	// TODO signal irreversible error
-	return hb_pair (start_offset, end_offset);
+	return hb_bytes_t ();
+      }
+      hb_bytes_t glyph ((const char *) this, end_offset - start_offset);
+
+      // if dropping hints, find hints region and subtract it
+      if (c->plan->drop_hints) {
+        unsigned int instruction_length;
+        if (!glyf.get_instruction_length (glyph, &instruction_length))
+        {
+          // TODO signal irreversible failure
+          return hb_bytes_t ();
+        }
+        glyph = hb_bytes_t (&glyph, glyph.length - instruction_length);
       }
-      return hb_pair (start_offset, end_offset);
+
+      return glyph;
     });
 
     glyf_prime->serialize (c->serializer, it);
 
+    // we know enough to write loca
+    // TODO calculate size, do we need two or four byte loca entries
+    unsigned int offset = 0;
+    HBUINT16 loca_entry;
+    loca *loca_prime = c->serializer->start_embed <loca> ();
+    + hb_enumerate (it)
+    | hb_apply ([&] (hb_pair_t<unsigned, hb_bytes_t> p) {
+      offset += p.second.length;
+      loca_entry = offset / 2;
+      c->serializer->embed(loca_entry);
+    });
+    // one for the road
+    c->serializer->embed(loca_entry);
+
     return_trace (true);
   }
 
@@ -412,45 +438,40 @@ struct glyf
       return true;
     }
 
-    bool get_instruction_offsets (unsigned int start_offset,
-				  unsigned int end_offset,
-				  unsigned int *instruction_start /* OUT */,
-				  unsigned int *instruction_end /* OUT */) const
+    bool get_instruction_length (hb_bytes_t glyph,
+				 unsigned int * length /* OUT */) const
     {
-      if (end_offset - start_offset < GlyphHeader::static_size)
+      /* Empty glyph; no instructions. */
+      if (glyph.get_size() < GlyphHeader::static_size)
       {
-	*instruction_start = 0;
-	*instruction_end = 0;
-	return true; /* Empty glyph; no instructions. */
+	*length = 0;
+	return true;
       }
-      const GlyphHeader &glyph_header = StructAtOffset<GlyphHeader> (glyf_table, start_offset);
+      unsigned int start = glyph.length;
+      unsigned int end = glyph.length;
+      const GlyphHeader &glyph_header = StructAtOffset<GlyphHeader> (&glyph, 0);
       int16_t num_contours = (int16_t) glyph_header.numberOfContours;
       if (num_contours < 0)
       {
 	CompositeGlyphHeader::Iterator composite_it;
-	if (unlikely (!CompositeGlyphHeader::get_iterator (
-	    (const char*) this->glyf_table + start_offset,
-	     end_offset - start_offset, &composite_it))) return false;
+	if (unlikely (!CompositeGlyphHeader::get_iterator (&glyph, glyph.length, &composite_it))) return false;
 	const CompositeGlyphHeader *last;
 	do {
 	  last = composite_it.current;
 	} while (composite_it.move_to_next ());
 
 	if ((uint16_t) last->flags & CompositeGlyphHeader::WE_HAVE_INSTRUCTIONS)
-	  *instruction_start = ((char *) last - (char *) glyf_table->dataZ.arrayZ) + last->get_size ();
-	else
-	  *instruction_start = end_offset;
-	*instruction_end = end_offset;
-	if (unlikely (*instruction_start > *instruction_end))
+	  start = ((char *) last - (char *) glyf_table->dataZ.arrayZ) + last->get_size ();
+	if (unlikely (start > end))
 	{
-	  DEBUG_MSG(SUBSET, nullptr, "Invalid instruction offset, %d is outside [%d, %d]", *instruction_start, start_offset, end_offset);
+	  DEBUG_MSG(SUBSET, nullptr, "Invalid instruction offset, %d is outside %d byte buffer", start, glyph.length);
 	  return false;
 	}
       }
       else
       {
-	unsigned int instruction_length_offset = start_offset + GlyphHeader::static_size + 2 * num_contours;
-	if (unlikely (instruction_length_offset + 2 > end_offset))
+	unsigned int instruction_length_offset = GlyphHeader::static_size + 2 * num_contours;
+	if (unlikely (instruction_length_offset + 2 > glyph.length))
 	{
 	  DEBUG_MSG(SUBSET, nullptr, "Glyph size is too short, missing field instructionLength.");
 	  return false;
@@ -459,15 +480,13 @@ struct glyf
 	const HBUINT16 &instruction_length = StructAtOffset<HBUINT16> (glyf_table, instruction_length_offset);
 	unsigned int start = instruction_length_offset + 2;
 	unsigned int end = start + (uint16_t) instruction_length;
-	if (unlikely (end > end_offset)) // Out of bounds of the current glyph
+	if (unlikely (end > glyph.length)) // Out of bounds of the current glyph
 	{
 	  DEBUG_MSG(SUBSET, nullptr, "The instructions array overruns the glyph's boundaries.");
 	  return false;
 	}
-
-	*instruction_start = start;
-	*instruction_end = end;
       }
+      *length = end - start;
       return true;
     }