[glyf] Move glyph bytes drop hints logic to GlyphHeader
This commit is contained in:
Ebrahim Byagowi
parent
1fb9c3b646
commit
b2628f1a3e
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@ -197,7 +197,7 @@ struct glyf
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return subset_glyph;
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subset_glyph.source_glyph = glyf.bytes_for_glyph (subset_glyph.old_gid, true);
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if (plan->drop_hints) subset_glyph.drop_hints (glyf);
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if (plan->drop_hints) subset_glyph.drop_hints_bytes ();
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else subset_glyph.dest_start = subset_glyph.source_glyph;
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return subset_glyph;
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@ -401,16 +401,15 @@ struct glyf
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unsigned int length (unsigned int instruction_len) const
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{ return instruction_len_offset () + 2 + instruction_len; }
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bool get_instruction_length (hb_bytes_t glyph, unsigned int *len) const
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unsigned int instructions_length (hb_bytes_t glyph) const
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{
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unsigned int instruction_length_offset = instruction_len_offset ();
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if (unlikely (instruction_length_offset + 2 > glyph.length)) return false;
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if (unlikely (instruction_length_offset + 2 > glyph.length)) return 0;
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const HBUINT16 &instructionLength = StructAtOffset<HBUINT16> (&glyph, instruction_length_offset);
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/* Out of bounds of the current glyph */
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if (unlikely (length (instructionLength) > glyph.length)) return false;
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*len = instructionLength;
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return true;
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if (unlikely (length (instructionLength) > glyph.length)) return 0;
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return instructionLength;
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}
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enum simple_glyph_flag_t
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@ -478,6 +477,14 @@ struct glyf
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GlyphHeader &glyph_header = const_cast<GlyphHeader &> (header);
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(HBUINT16 &) StructAtOffset<HBUINT16> (&glyph_header, instruction_len_offset ()) = 0;
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}
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void drop_hints_bytes (hb_bytes_t source_glyph, hb_bytes_t &dest_start, hb_bytes_t &dest_end) const
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{
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unsigned int instructions_len = instructions_length (source_glyph);
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unsigned int glyph_length = length (instructions_len);
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dest_start = source_glyph.sub_array (0, glyph_length - instructions_len);
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dest_end = source_glyph.sub_array (glyph_length, source_glyph.length - glyph_length);
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}
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};
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struct CompositeHeader
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@ -488,20 +495,19 @@ struct glyf
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composite_iter_t get_iterator (hb_bytes_t glyph) const
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{ return composite_iter_t (glyph, &StructAfter<CompositeGlyphHeader, GlyphHeader> (header)); }
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bool get_instruction_length (hb_bytes_t glyph, unsigned int *length) const
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unsigned int instructions_length (hb_bytes_t glyph) const
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{
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unsigned int start = glyph.length;
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unsigned int end = glyph.length;
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const CompositeGlyphHeader *last = nullptr;
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for (auto &item : get_iterator (glyph))
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last = &item;
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if (unlikely (!last)) return false;
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if (unlikely (!last)) return 0;
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if ((uint16_t) last->flags & CompositeGlyphHeader::WE_HAVE_INSTRUCTIONS)
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start = (char *) last - &glyph + last->get_size ();
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if (unlikely (start > end)) return false;
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*length = end - start;
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return true;
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if (unlikely (start > end)) return 0;
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return end - start;
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}
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/* Trimming for composites not implemented.
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@ -518,16 +524,15 @@ struct glyf
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flags = (uint16_t) flags & ~OT::glyf::CompositeGlyphHeader::WE_HAVE_INSTRUCTIONS;
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}
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}
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};
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const SimpleHeader as_simple () const { return SimpleHeader (*this); }
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SimpleHeader as_simple () { return SimpleHeader (*this); }
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const CompositeHeader as_composite () const { return CompositeHeader (*this); }
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CompositeHeader as_composite () { return CompositeHeader (*this); }
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/* Chop instructions off the end */
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void drop_hints_bytes (hb_bytes_t source_glyph, hb_bytes_t &dest_start) const
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{ dest_start = source_glyph.sub_array (0, source_glyph.length - instructions_length (source_glyph)); }
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};
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enum glyph_type_t { EMPTY, SIMPLE, COMPOSITE };
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glyph_type_t get_type () const
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unsigned get_type () const
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{
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if (is_simple_glyph ()) return SIMPLE;
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else if (is_composite_glyph ()) return COMPOSITE;
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@ -537,28 +542,16 @@ struct glyf
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composite_iter_t get_composite_iterator (hb_bytes_t glyph) const
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{
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if (!is_composite_glyph ()) return composite_iter_t ();
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return as_composite ().get_iterator (glyph);
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}
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bool get_instruction_length (hb_bytes_t glyph, unsigned int *length) const
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{
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switch (get_type ())
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{
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case COMPOSITE: return as_composite ().get_instruction_length (glyph, length);
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case SIMPLE: return as_simple ().get_instruction_length (glyph, length);
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default:
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case EMPTY: *length = 0; return glyph.length == 0; /* only 0 byte glyphs are healthy when missing GlyphHeader */
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}
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return CompositeHeader (*this).get_iterator (glyph);
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}
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hb_bytes_t bytes_without_padding (hb_bytes_t glyph_bytes) const
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{
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switch (get_type ())
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{
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case COMPOSITE: return as_composite ().bytes_without_padding (glyph_bytes);
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case SIMPLE: return as_simple ().bytes_without_padding (glyph_bytes);
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default:
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case EMPTY: return glyph_bytes;
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case COMPOSITE: return CompositeHeader (*this).bytes_without_padding (glyph_bytes);
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case SIMPLE: return SimpleHeader (*this).bytes_without_padding (glyph_bytes);
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default: return glyph_bytes;
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}
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}
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@ -566,10 +559,19 @@ struct glyf
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{
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switch (get_type ())
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{
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case COMPOSITE: as_composite ().drop_hints (glyph_bytes); return;
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case SIMPLE: as_simple ().drop_hints (); return;
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default:
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case EMPTY: return;
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case COMPOSITE: CompositeHeader (*this).drop_hints (glyph_bytes); return;
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case SIMPLE: SimpleHeader (*this).drop_hints (); return;
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default: return;
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}
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}
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void drop_hints_bytes (hb_bytes_t source_glyph, hb_bytes_t &dest_start, hb_bytes_t &dest_end) const
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{
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switch (get_type ())
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{
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case COMPOSITE: CompositeHeader (*this).drop_hints_bytes (source_glyph, dest_start); return;
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case SIMPLE: SimpleHeader (*this).drop_hints_bytes (source_glyph, dest_start, dest_end); return;
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default: return;
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}
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}
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@ -1074,28 +1076,8 @@ struct glyf
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return_trace (true);
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}
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void drop_hints (const OT::glyf::accelerator_t& glyf)
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{
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if (source_glyph.length == 0) return;
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unsigned int instruction_len = 0;
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const GlyphHeader& header = *source_glyph.as<GlyphHeader> ();
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if (!header.get_instruction_length (source_glyph, &instruction_len))
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/* Unable to read instruction length */
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return;
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if (header.is_composite_glyph ())
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/* just chop instructions off the end for composite glyphs */
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dest_start = hb_bytes_t (&source_glyph, source_glyph.length - instruction_len);
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else
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{
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unsigned int glyph_length = GlyphHeader::SimpleHeader (header).length (instruction_len);
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dest_start = hb_bytes_t (&source_glyph, glyph_length - instruction_len);
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dest_end = hb_bytes_t (&source_glyph + glyph_length,
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source_glyph.length - glyph_length);
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}
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}
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void drop_hints_bytes ()
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{ source_glyph.as<GlyphHeader> ()->drop_hints_bytes (source_glyph, dest_start, dest_end); }
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unsigned int length () const { return dest_start.length + dest_end.length; }
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/* pad to 2 to ensure 2-byte loca will be ok */
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