/* * Copyright © 2015 Google, Inc. * * This is part of HarfBuzz, a text shaping library. * * Permission is hereby granted, without written agreement and without * license or royalty fees, to use, copy, modify, and distribute this * software and its documentation for any purpose, provided that the * above copyright notice and the following two paragraphs appear in * all copies of this software. * * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH * DAMAGE. * * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. * * Google Author(s): Behdad Esfahbod, Garret Rieger, Roderick Sheeter */ #ifndef HB_OT_GLYF_TABLE_HH #define HB_OT_GLYF_TABLE_HH #include "hb-open-type.hh" #include "hb-ot-head-table.hh" namespace OT { /* * loca -- Index to Location * https://docs.microsoft.com/en-us/typography/opentype/spec/loca */ #define HB_OT_TAG_loca HB_TAG('l','o','c','a') struct loca { friend struct glyf; static constexpr hb_tag_t tableTag = HB_OT_TAG_loca; bool sanitize (hb_sanitize_context_t *c HB_UNUSED) const { TRACE_SANITIZE (this); return_trace (true); } protected: UnsizedArrayOf dataZ; /* Location data. */ public: DEFINE_SIZE_MIN (0); /* In reality, this is UNBOUNDED() type; but since we always * check the size externally, allow Null() object of it by * defining it _MIN instead. */ }; /* * glyf -- TrueType Glyph Data * https://docs.microsoft.com/en-us/typography/opentype/spec/glyf */ #define HB_OT_TAG_glyf HB_TAG('g','l','y','f') struct glyf { static constexpr hb_tag_t tableTag = HB_OT_TAG_glyf; bool sanitize (hb_sanitize_context_t *c HB_UNUSED) const { TRACE_SANITIZE (this); /* We don't check for anything specific here. The users of the * struct do all the hard work... */ return_trace (true); } template static bool _add_loca_and_head (hb_subset_plan_t * plan, Iterator padded_offsets) { unsigned int max_offset = + padded_offsets | hb_reduce (hb_max, 0); unsigned num_offsets = padded_offsets.len () + 1; bool use_short_loca = max_offset < 0x1FFFF; unsigned entry_size = use_short_loca ? 2 : 4; char *loca_prime_data = (char *) calloc (entry_size, num_offsets); if (unlikely (!loca_prime_data)) return false; if (use_short_loca) _write_loca (padded_offsets, 1, hb_array ((HBUINT16*) loca_prime_data, num_offsets)); else _write_loca (padded_offsets, 0, hb_array ((HBUINT32*) loca_prime_data, num_offsets)); hb_blob_t * loca_blob = hb_blob_create (loca_prime_data, entry_size * num_offsets, HB_MEMORY_MODE_WRITABLE, loca_prime_data, free); bool result = plan->add_table (HB_OT_TAG_loca, loca_blob) && _add_head_and_set_loca_version(plan, use_short_loca); hb_blob_destroy (loca_blob); return result; } template static void _write_loca (IteratorIn it, unsigned right_shift, IteratorOut dest) { unsigned int offset = 0; dest << 0; + it | hb_map ([=, &offset] (unsigned int padded_size) { offset += padded_size; DEBUG_MSG(SUBSET, nullptr, "loca entry offset %d", offset); return offset >> right_shift; }) | hb_sink (dest) ; } // requires source of SubsetGlyph complains the identifier isn't declared template bool serialize(hb_serialize_context_t *c, Iterator it, const hb_subset_plan_t *plan) { TRACE_SERIALIZE (this); + it | hb_apply ([=] (const SubsetGlyph& _) { _.serialize (c, plan); }) ; return_trace (true); } bool subset (hb_subset_context_t *c) const { TRACE_SUBSET (this); glyf *glyf_prime = c->serializer->start_embed (); if (unlikely (!c->serializer->check_success (glyf_prime))) return_trace (false); // Byte region(s) per glyph to output // unpadded, hints removed if so requested // If we fail to process a glyph we produce an empty (0-length) glyph hb_vector_t glyphs; _populate_subset_glyphs (c->plan, &glyphs); glyf_prime->serialize (c->serializer, hb_iter (glyphs), c->plan); auto padded_offsets = + hb_iter (glyphs) | hb_map (&SubsetGlyph::padded_size) ; return_trace (c->serializer->check_success (_add_loca_and_head (c->plan, padded_offsets))); } template void _populate_subset_glyphs (const hb_subset_plan_t * plan, hb_vector_t * glyphs /* OUT */) const { OT::glyf::accelerator_t glyf; glyf.init (plan->source); + hb_range (plan->num_output_glyphs ()) | hb_map ([&] (hb_codepoint_t new_gid) { SubsetGlyph subset_glyph; subset_glyph.new_gid = new_gid; // should never fail: all old gids should be mapped if (!plan->old_gid_for_new_gid (new_gid, &subset_glyph.old_gid)) return subset_glyph; subset_glyph.source_glyph = glyf.bytes_for_glyph ((const char *) this, subset_glyph.old_gid); if (plan->drop_hints) subset_glyph.drop_hints (glyf); else subset_glyph.dest_start = subset_glyph.source_glyph; return subset_glyph; }) | hb_sink (glyphs) ; glyf.fini(); } static void _fix_component_gids (const hb_subset_plan_t *plan, hb_bytes_t glyph) { OT::glyf::CompositeGlyphHeader::Iterator iterator; if (OT::glyf::CompositeGlyphHeader::get_iterator (&glyph, glyph.length, &iterator)) { do { hb_codepoint_t new_gid; if (!plan->new_gid_for_old_gid (iterator.current->glyphIndex, &new_gid)) continue; ((OT::glyf::CompositeGlyphHeader *) iterator.current)->glyphIndex = new_gid; } while (iterator.move_to_next ()); } } static void _zero_instruction_length (hb_bytes_t glyph) { const GlyphHeader &glyph_header = StructAtOffset (&glyph, 0); int16_t num_contours = (int16_t) glyph_header.numberOfContours; if (num_contours <= 0) return; // only for simple glyphs const HBUINT16 &instruction_length = StructAtOffset (&glyph, GlyphHeader::static_size + 2 * num_contours); (HBUINT16 &) instruction_length = 0; } static bool _remove_composite_instruction_flag (hb_bytes_t glyph) { const GlyphHeader &glyph_header = StructAtOffset (&glyph, 0); if (glyph_header.numberOfContours >= 0) return true; // only for composites /* remove WE_HAVE_INSTRUCTIONS from flags in dest */ OT::glyf::CompositeGlyphHeader::Iterator composite_it; if (unlikely (!OT::glyf::CompositeGlyphHeader::get_iterator (&glyph, glyph.length, &composite_it))) return false; const OT::glyf::CompositeGlyphHeader *composite_header; do { composite_header = composite_it.current; OT::HBUINT16 *flags = const_cast (&composite_header->flags); *flags = (uint16_t) *flags & ~OT::glyf::CompositeGlyphHeader::WE_HAVE_INSTRUCTIONS; } while (composite_it.move_to_next ()); return true; } static bool _add_head_and_set_loca_version (hb_subset_plan_t *plan, bool use_short_loca) { hb_blob_t *head_blob = hb_sanitize_context_t ().reference_table (plan->source); hb_blob_t *head_prime_blob = hb_blob_copy_writable_or_fail (head_blob); hb_blob_destroy (head_blob); if (unlikely (!head_prime_blob)) return false; head *head_prime = (head *) hb_blob_get_data_writable (head_prime_blob, nullptr); head_prime->indexToLocFormat = use_short_loca ? 0 : 1; bool success = plan->add_table (HB_OT_TAG_head, head_prime_blob); hb_blob_destroy (head_prime_blob); return success; } struct GlyphHeader { HBINT16 numberOfContours; /* If the number of contours is * greater than or equal to zero, * this is a simple glyph; if negative, * this is a composite glyph. */ FWORD xMin; /* Minimum x for coordinate data. */ FWORD yMin; /* Minimum y for coordinate data. */ FWORD xMax; /* Maximum x for coordinate data. */ FWORD yMax; /* Maximum y for coordinate data. */ DEFINE_SIZE_STATIC (10); }; struct CompositeGlyphHeader { enum composite_glyph_flag_t { ARG_1_AND_2_ARE_WORDS = 0x0001, ARGS_ARE_XY_VALUES = 0x0002, ROUND_XY_TO_GRID = 0x0004, WE_HAVE_A_SCALE = 0x0008, MORE_COMPONENTS = 0x0020, WE_HAVE_AN_X_AND_Y_SCALE = 0x0040, WE_HAVE_A_TWO_BY_TWO = 0x0080, WE_HAVE_INSTRUCTIONS = 0x0100, USE_MY_METRICS = 0x0200, OVERLAP_COMPOUND = 0x0400, SCALED_COMPONENT_OFFSET = 0x0800, UNSCALED_COMPONENT_OFFSET = 0x1000 }; HBUINT16 flags; GlyphID glyphIndex; unsigned int get_size () const { unsigned int size = min_size; // arg1 and 2 are int16 if (flags & ARG_1_AND_2_ARE_WORDS) size += 4; // arg1 and 2 are int8 else size += 2; // One x 16 bit (scale) if (flags & WE_HAVE_A_SCALE) size += 2; // Two x 16 bit (xscale, yscale) else if (flags & WE_HAVE_AN_X_AND_Y_SCALE) size += 4; // Four x 16 bit (xscale, scale01, scale10, yscale) else if (flags & WE_HAVE_A_TWO_BY_TWO) size += 8; return size; } // TODO rewrite using new iterator framework if possible struct Iterator { const char *glyph_start; const char *glyph_end; const CompositeGlyphHeader *current; bool move_to_next () { if (current->flags & CompositeGlyphHeader::MORE_COMPONENTS) { const CompositeGlyphHeader *possible = &StructAfter (*current); if (!in_range (possible)) return false; current = possible; return true; } return false; } bool in_range (const CompositeGlyphHeader *composite) const { return (const char *) composite >= glyph_start && ((const char *) composite + CompositeGlyphHeader::min_size) <= glyph_end && ((const char *) composite + composite->get_size ()) <= glyph_end; } }; static bool get_iterator (const char * glyph_data, unsigned int length, CompositeGlyphHeader::Iterator *iterator /* OUT */) { if (length < GlyphHeader::static_size) return false; /* Empty glyph; zero extents. */ const GlyphHeader &glyph_header = StructAtOffset (glyph_data, 0); if (glyph_header.numberOfContours < 0) { const CompositeGlyphHeader *possible = &StructAfter (glyph_header); iterator->glyph_start = glyph_data; iterator->glyph_end = (const char *) glyph_data + length; if (!iterator->in_range (possible)) return false; iterator->current = possible; return true; } return false; } DEFINE_SIZE_MIN (4); }; struct accelerator_t { void init (hb_face_t *face) { memset (this, 0, sizeof (accelerator_t)); const OT::head &head = *face->table.head; if (head.indexToLocFormat > 1 || head.glyphDataFormat != 0) /* Unknown format. Leave num_glyphs=0, that takes care of disabling us. */ return; short_offset = 0 == head.indexToLocFormat; loca_table = hb_sanitize_context_t ().reference_table (face); glyf_table = hb_sanitize_context_t ().reference_table (face); num_glyphs = hb_max (1u, loca_table.get_length () / (short_offset ? 2 : 4)) - 1; } void fini () { loca_table.destroy (); glyf_table.destroy (); } /* * Returns true if the referenced glyph is a valid glyph and a composite glyph. * If true is returned a pointer to the composite glyph will be written into * composite. */ bool get_composite (hb_codepoint_t glyph, CompositeGlyphHeader::Iterator *composite /* OUT */) const { if (unlikely (!num_glyphs)) return false; unsigned int start_offset, end_offset; if (!get_offsets (glyph, &start_offset, &end_offset)) return false; /* glyph not found */ return CompositeGlyphHeader::get_iterator ((const char *) this->glyf_table + start_offset, end_offset - start_offset, composite); } enum simple_glyph_flag_t { FLAG_ON_CURVE = 0x01, FLAG_X_SHORT = 0x02, FLAG_Y_SHORT = 0x04, FLAG_REPEAT = 0x08, FLAG_X_SAME = 0x10, FLAG_Y_SAME = 0x20, FLAG_RESERVED1 = 0x40, FLAG_RESERVED2 = 0x80 }; /* based on FontTools _g_l_y_f.py::trim */ bool remove_padding (unsigned int start_offset, unsigned int *end_offset) const { if (*end_offset - start_offset < GlyphHeader::static_size) return true; const char *glyph = ((const char *) glyf_table) + start_offset; const char * const glyph_end = glyph + (*end_offset - start_offset); const GlyphHeader &glyph_header = StructAtOffset (glyph, 0); int16_t num_contours = (int16_t) glyph_header.numberOfContours; if (num_contours < 0) /* Trimming for composites not implemented. * If removing hints it falls out of that. */ return true; else if (num_contours > 0) { /* simple glyph w/contours, possibly trimmable */ glyph += GlyphHeader::static_size + 2 * num_contours; if (unlikely (glyph + 2 >= glyph_end)) return false; uint16_t nCoordinates = (uint16_t) StructAtOffset (glyph - 2, 0) + 1; uint16_t nInstructions = (uint16_t) StructAtOffset (glyph, 0); glyph += 2 + nInstructions; if (unlikely (glyph + 2 >= glyph_end)) return false; unsigned int coordBytes = 0; unsigned int coordsWithFlags = 0; while (glyph < glyph_end) { uint8_t flag = (uint8_t) *glyph; glyph++; unsigned int repeat = 1; if (flag & FLAG_REPEAT) { if (glyph >= glyph_end) { DEBUG_MSG(SUBSET, nullptr, "Bad flag"); return false; } repeat = ((uint8_t) *glyph) + 1; glyph++; } unsigned int xBytes, yBytes; xBytes = yBytes = 0; if (flag & FLAG_X_SHORT) xBytes = 1; else if ((flag & FLAG_X_SAME) == 0) xBytes = 2; if (flag & FLAG_Y_SHORT) yBytes = 1; else if ((flag & FLAG_Y_SAME) == 0) yBytes = 2; coordBytes += (xBytes + yBytes) * repeat; coordsWithFlags += repeat; if (coordsWithFlags >= nCoordinates) break; } if (coordsWithFlags != nCoordinates) { DEBUG_MSG(SUBSET, nullptr, "Expect %d coords to have flags, got flags for %d", nCoordinates, coordsWithFlags); return false; } glyph += coordBytes; if (glyph < glyph_end) *end_offset -= glyph_end - glyph; } return true; } bool get_offsets (hb_codepoint_t glyph, unsigned int *start_offset /* OUT */, unsigned int *end_offset /* OUT */) const { if (unlikely (glyph >= num_glyphs)) return false; if (short_offset) { const HBUINT16 *offsets = (const HBUINT16 *) loca_table->dataZ.arrayZ; *start_offset = 2 * offsets[glyph]; *end_offset = 2 * offsets[glyph + 1]; } else { const HBUINT32 *offsets = (const HBUINT32 *) loca_table->dataZ.arrayZ; *start_offset = offsets[glyph]; *end_offset = offsets[glyph + 1]; } if (*start_offset > *end_offset || *end_offset > glyf_table.get_length ()) return false; return true; } bool get_instruction_length (hb_bytes_t glyph, unsigned int * length /* OUT */) const { /* Empty glyph; no instructions. */ if (glyph.length < GlyphHeader::static_size) { *length = 0; // only 0 byte glyphs are healthy when missing GlyphHeader return glyph.length == 0; } const GlyphHeader &glyph_header = StructAtOffset (&glyph, 0); int16_t num_contours = (int16_t) glyph_header.numberOfContours; if (num_contours < 0) { unsigned int start = glyph.length; unsigned int end = glyph.length; unsigned int glyph_offset = &glyph - glyf_table; CompositeGlyphHeader::Iterator composite_it; 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) start = ((char *) last - (char *) glyf_table->dataZ.arrayZ) + last->get_size () - glyph_offset; if (unlikely (start > end)) { DEBUG_MSG(SUBSET, nullptr, "Invalid instruction offset, %d is outside %d byte buffer", start, glyph.length); return false; } *length = end - start; } else { 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; } const HBUINT16 &instruction_length = StructAtOffset (&glyph, instruction_length_offset); if (unlikely (instruction_length_offset + instruction_length > glyph.length)) // Out of bounds of the current glyph { DEBUG_MSG(SUBSET, nullptr, "The instructions array overruns the glyph's boundaries."); return false; } *length = (uint16_t) instruction_length; } return true; } bool get_extents (hb_codepoint_t glyph, hb_glyph_extents_t *extents) const { unsigned int start_offset, end_offset; if (!get_offsets (glyph, &start_offset, &end_offset)) return false; if (end_offset - start_offset < GlyphHeader::static_size) return true; /* Empty glyph; zero extents. */ const GlyphHeader &glyph_header = StructAtOffset (glyf_table, start_offset); extents->x_bearing = hb_min (glyph_header.xMin, glyph_header.xMax); extents->y_bearing = hb_max (glyph_header.yMin, glyph_header.yMax); extents->width = hb_max (glyph_header.xMin, glyph_header.xMax) - extents->x_bearing; extents->height = hb_min (glyph_header.yMin, glyph_header.yMax) - extents->y_bearing; return true; } hb_bytes_t bytes_for_glyph (const char * glyf, hb_codepoint_t gid) { unsigned int start_offset, end_offset; if (unlikely (!(get_offsets (gid, &start_offset, &end_offset) && remove_padding (start_offset, &end_offset)))) { DEBUG_MSG(SUBSET, nullptr, "Unable to get offset or remove padding for %d", gid); return hb_bytes_t (); } hb_bytes_t glyph = hb_bytes_t (glyf + start_offset, end_offset - start_offset); if (glyph.length == 0) return glyph; if (unlikely (glyph.length < GlyphHeader::static_size)) { DEBUG_MSG(SUBSET, nullptr, "Glyph size smaller than minimum header %d", gid); return hb_bytes_t (); } return glyph; } private: bool short_offset; unsigned int num_glyphs; hb_blob_ptr_t loca_table; hb_blob_ptr_t glyf_table; }; struct SubsetGlyph { hb_codepoint_t new_gid; hb_codepoint_t old_gid; hb_bytes_t source_glyph; hb_bytes_t dest_start; // region of source_glyph to copy first hb_bytes_t dest_end; // region of source_glyph to copy second bool serialize (hb_serialize_context_t *c, const hb_subset_plan_t *plan) const { TRACE_SERIALIZE (this); hb_bytes_t dest_glyph = dest_start.copy(c); dest_glyph = hb_bytes_t (&dest_glyph, dest_glyph.length + dest_end.copy(c).length); unsigned int pad_length = padding (); DEBUG_MSG(SUBSET, nullptr, "serialize %d byte glyph, width %d pad %d", dest_glyph.length, dest_glyph.length + pad_length, pad_length); HBUINT8 pad; pad = 0; while (pad_length > 0) { c->embed(pad); pad_length--; } if (dest_glyph.length) { _fix_component_gids (plan, dest_glyph); if (plan->drop_hints) { _zero_instruction_length (dest_glyph); c->check_success (_remove_composite_instruction_flag (dest_glyph)); } } return_trace (true); } void drop_hints (const OT::glyf::accelerator_t& glyf) { if (source_glyph.length == 0) return; unsigned int instruction_length = 0; if (!glyf.get_instruction_length (source_glyph, &instruction_length)) { DEBUG_MSG(SUBSET, nullptr, "Unable to read instruction length for new_gid %d", new_gid); return ; } const GlyphHeader& header = StructAtOffset (&source_glyph, 0); int16_t num_contours = (int16_t) header.numberOfContours; DEBUG_MSG(SUBSET, nullptr, "new_gid %d (%d contours) drop %d instruction bytes from %d byte source glyph", new_gid, num_contours, instruction_length, source_glyph.length); if (num_contours < 0) { // composite, just chop instructions off the end dest_start = hb_bytes_t (&source_glyph, source_glyph.length - instruction_length); } else { // simple glyph dest_start = hb_bytes_t (&source_glyph, GlyphHeader::static_size + 2 * header.numberOfContours + 2); dest_end = hb_bytes_t (&source_glyph + dest_start.length + instruction_length, source_glyph.length - dest_start.length - instruction_length); DEBUG_MSG(SUBSET, nullptr, "source_len %d start len %d instruction_len %d end len %d", source_glyph.length, dest_start.length, instruction_length, dest_end.length); } } unsigned int length () const { return dest_start.length + dest_end.length; } // pad to 2 to ensure 2-byte loca will be ok unsigned int padding () const { return length () % 2; } unsigned int padded_size () const { return length () + padding (); } }; protected: UnsizedArrayOf dataZ; /* Glyphs data. */ public: DEFINE_SIZE_MIN (0); /* In reality, this is UNBOUNDED() type; but since we always * check the size externally, allow Null() object of it by * defining it _MIN instead. */ }; struct glyf_accelerator_t : glyf::accelerator_t {}; } /* namespace OT */ #endif /* HB_OT_GLYF_TABLE_HH */