| /* |
| * Copyright © 2018 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): Garret Rieger, Roderick Sheeter |
| */ |
| |
| #include "hb-open-type.hh" |
| #include "hb-ot-glyf-table.hh" |
| #include "hb-set.h" |
| #include "hb-subset-glyf.hh" |
| |
| struct loca_data_t |
| { |
| bool is_short; |
| void *data; |
| unsigned int size; |
| |
| inline bool |
| _write_loca_entry (unsigned int id, |
| unsigned int offset) |
| { |
| unsigned int entry_size = is_short ? sizeof (OT::HBUINT16) : sizeof (OT::HBUINT32); |
| if ((id + 1) * entry_size <= size) |
| { |
| if (is_short) { |
| ((OT::HBUINT16*) data) [id].set (offset / 2); |
| } else { |
| ((OT::HBUINT32*) data) [id].set (offset); |
| } |
| return true; |
| } |
| |
| // Offset was not written because the write is out of bounds. |
| DEBUG_MSG(SUBSET, |
| nullptr, |
| "WARNING: Attempted to write an out of bounds loca entry at index %d. Loca size is %d.", |
| id, |
| size); |
| return false; |
| } |
| }; |
| |
| /** |
| * If hints are being dropped find the range which in glyf at which |
| * the hinting instructions are located. Add them to the instruction_ranges |
| * vector. |
| */ |
| static bool |
| _add_instructions_range (const OT::glyf::accelerator_t &glyf, |
| hb_codepoint_t glyph_id, |
| unsigned int glyph_start_offset, |
| unsigned int glyph_end_offset, |
| bool drop_hints, |
| hb_vector_t<unsigned int> *instruction_ranges /* OUT */) |
| { |
| if (!instruction_ranges->resize (instruction_ranges->length + 2)) |
| { |
| DEBUG_MSG(SUBSET, nullptr, "Failed to resize instruction_ranges."); |
| return false; |
| } |
| unsigned int *instruction_start = &(*instruction_ranges)[instruction_ranges->length - 2]; |
| *instruction_start = 0; |
| unsigned int *instruction_end = &(*instruction_ranges)[instruction_ranges->length - 1]; |
| *instruction_end = 0; |
| |
| if (drop_hints) |
| { |
| if (unlikely (!glyf.get_instruction_offsets (glyph_start_offset, glyph_end_offset, |
| instruction_start, instruction_end))) |
| { |
| DEBUG_MSG(SUBSET, nullptr, "Unable to get instruction offsets for %d", glyph_id); |
| return false; |
| } |
| } |
| |
| return true; |
| } |
| |
| static bool |
| _calculate_glyf_and_loca_prime_size (const OT::glyf::accelerator_t &glyf, |
| const hb_subset_plan_t *plan, |
| loca_data_t *loca_data, /* OUT */ |
| unsigned int *glyf_size /* OUT */, |
| hb_vector_t<unsigned int> *instruction_ranges /* OUT */) |
| { |
| unsigned int total = 0; |
| |
| hb_codepoint_t next_glyph = HB_SET_VALUE_INVALID; |
| while (plan->glyphset ()->next (&next_glyph)) |
| { |
| unsigned int start_offset, end_offset; |
| if (unlikely (!(glyf.get_offsets (next_glyph, &start_offset, &end_offset) && |
| glyf.remove_padding (start_offset, &end_offset)))) |
| { |
| DEBUG_MSG(SUBSET, nullptr, "Invalid gid %d", next_glyph); |
| start_offset = end_offset = 0; |
| } |
| |
| bool is_zero_length = end_offset - start_offset < OT::glyf::GlyphHeader::static_size; |
| if (!_add_instructions_range (glyf, |
| next_glyph, |
| start_offset, |
| end_offset, |
| plan->drop_hints && !is_zero_length, |
| instruction_ranges)) |
| return false; |
| |
| if (is_zero_length) |
| continue; /* 0-length glyph */ |
| |
| total += end_offset - start_offset |
| - ((*instruction_ranges)[instruction_ranges->length - 1] |
| - (*instruction_ranges)[instruction_ranges->length - 2]); |
| /* round2 so short loca will work */ |
| total += total % 2; |
| } |
| |
| *glyf_size = total; |
| loca_data->is_short = (total <= 131070); |
| loca_data->size = (plan->num_output_glyphs () + 1) |
| * (loca_data->is_short ? sizeof (OT::HBUINT16) : sizeof (OT::HBUINT32)); |
| |
| DEBUG_MSG(SUBSET, nullptr, "preparing to subset glyf: final size %d, loca size %d, using %s loca", |
| total, |
| loca_data->size, |
| loca_data->is_short ? "short" : "long"); |
| return true; |
| } |
| |
| static void |
| _update_components (const hb_subset_plan_t *plan, |
| char *glyph_start, |
| unsigned int length) |
| { |
| OT::glyf::CompositeGlyphHeader::Iterator iterator; |
| if (OT::glyf::CompositeGlyphHeader::get_iterator (glyph_start, |
| 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.set (new_gid); |
| } while (iterator.move_to_next ()); |
| } |
| } |
| |
| static bool _remove_composite_instruction_flag (char *glyf_prime, unsigned int length) |
| { |
| /* remove WE_HAVE_INSTRUCTIONS from flags in dest */ |
| OT::glyf::CompositeGlyphHeader::Iterator composite_it; |
| if (unlikely (!OT::glyf::CompositeGlyphHeader::get_iterator (glyf_prime, length, &composite_it))) return false; |
| const OT::glyf::CompositeGlyphHeader *glyph; |
| do { |
| glyph = composite_it.current; |
| OT::HBUINT16 *flags = const_cast<OT::HBUINT16 *> (&glyph->flags); |
| flags->set ( (uint16_t) *flags & ~OT::glyf::CompositeGlyphHeader::WE_HAVE_INSTRUCTIONS); |
| } while (composite_it.move_to_next ()); |
| return true; |
| } |
| |
| static bool |
| _write_glyf_and_loca_prime (const hb_subset_plan_t *plan, |
| const OT::glyf::accelerator_t &glyf, |
| const char *glyf_data, |
| hb_vector_t<unsigned int> &instruction_ranges, |
| unsigned int glyf_prime_size, |
| char *glyf_prime_data /* OUT */, |
| loca_data_t *loca_prime /* OUT */) |
| { |
| char *glyf_prime_data_next = glyf_prime_data; |
| |
| bool success = true; |
| |
| |
| unsigned int i = 0; |
| hb_codepoint_t new_gid; |
| for (new_gid = 0; new_gid < plan->num_output_glyphs (); new_gid++) |
| { |
| hb_codepoint_t old_gid; |
| if (!plan->old_gid_for_new_gid (new_gid, &old_gid)) |
| { |
| // Empty glyph, add a loca entry and carry on. |
| loca_prime->_write_loca_entry (new_gid, |
| glyf_prime_data_next - glyf_prime_data); |
| continue; |
| } |
| |
| |
| unsigned int start_offset, end_offset; |
| if (unlikely (!(glyf.get_offsets (old_gid, &start_offset, &end_offset) && |
| glyf.remove_padding (start_offset, &end_offset)))) |
| end_offset = start_offset = 0; |
| |
| unsigned int instruction_start = instruction_ranges[i * 2]; |
| unsigned int instruction_end = instruction_ranges[i * 2 + 1]; |
| |
| int length = end_offset - start_offset - (instruction_end - instruction_start); |
| |
| if (glyf_prime_data_next + length > glyf_prime_data + glyf_prime_size) |
| { |
| DEBUG_MSG(SUBSET, |
| nullptr, |
| "WARNING: Attempted to write an out of bounds glyph entry for gid %d (length %d)", |
| i, length); |
| return false; |
| } |
| |
| if (instruction_start == instruction_end) |
| memcpy (glyf_prime_data_next, glyf_data + start_offset, length); |
| else |
| { |
| memcpy (glyf_prime_data_next, glyf_data + start_offset, instruction_start - start_offset); |
| memcpy (glyf_prime_data_next + instruction_start - start_offset, glyf_data + instruction_end, end_offset - instruction_end); |
| /* if the instructions end at the end this was a composite glyph, else simple */ |
| if (instruction_end == end_offset) |
| { |
| if (unlikely (!_remove_composite_instruction_flag (glyf_prime_data_next, length))) return false; |
| } |
| else |
| /* zero instruction length, which is just before instruction_start */ |
| memset (glyf_prime_data_next + instruction_start - start_offset - 2, 0, 2); |
| } |
| |
| success = success && loca_prime->_write_loca_entry (new_gid, |
| glyf_prime_data_next - glyf_prime_data); |
| _update_components (plan, glyf_prime_data_next, length); |
| |
| // TODO: don't align to two bytes if using long loca. |
| glyf_prime_data_next += length + (length % 2); // Align to 2 bytes for short loca. |
| |
| i++; |
| } |
| |
| // loca table has n+1 entries where the last entry signifies the end location of the last |
| // glyph. |
| success = success && loca_prime->_write_loca_entry (new_gid, |
| glyf_prime_data_next - glyf_prime_data); |
| return success; |
| } |
| |
| static bool |
| _hb_subset_glyf_and_loca (const OT::glyf::accelerator_t &glyf, |
| const char *glyf_data, |
| hb_subset_plan_t *plan, |
| bool *use_short_loca, |
| hb_blob_t **glyf_prime_blob /* OUT */, |
| hb_blob_t **loca_prime_blob /* OUT */) |
| { |
| // TODO(grieger): Sanity check allocation size for the new table. |
| loca_data_t loca_prime; |
| unsigned int glyf_prime_size; |
| hb_vector_t<unsigned int> instruction_ranges; |
| instruction_ranges.init (); |
| |
| if (unlikely (!_calculate_glyf_and_loca_prime_size (glyf, |
| plan, |
| &loca_prime, |
| &glyf_prime_size, |
| &instruction_ranges))) { |
| instruction_ranges.fini (); |
| return false; |
| } |
| *use_short_loca = loca_prime.is_short; |
| |
| char *glyf_prime_data = (char *) calloc (1, glyf_prime_size); |
| loca_prime.data = (void *) calloc (1, loca_prime.size); |
| if (unlikely (!_write_glyf_and_loca_prime (plan, glyf, glyf_data, |
| instruction_ranges, |
| glyf_prime_size, glyf_prime_data, |
| &loca_prime))) { |
| free (glyf_prime_data); |
| free (loca_prime.data); |
| instruction_ranges.fini (); |
| return false; |
| } |
| instruction_ranges.fini (); |
| |
| *glyf_prime_blob = hb_blob_create (glyf_prime_data, |
| glyf_prime_size, |
| HB_MEMORY_MODE_READONLY, |
| glyf_prime_data, |
| free); |
| *loca_prime_blob = hb_blob_create ((char *) loca_prime.data, |
| loca_prime.size, |
| HB_MEMORY_MODE_READONLY, |
| loca_prime.data, |
| free); |
| return true; |
| } |
| |
| /** |
| * hb_subset_glyf: |
| * Subsets the glyph table according to a provided plan. |
| * |
| * Return value: subsetted glyf table. |
| * |
| * Since: 1.7.5 |
| **/ |
| bool |
| hb_subset_glyf_and_loca (hb_subset_plan_t *plan, |
| bool *use_short_loca, /* OUT */ |
| hb_blob_t **glyf_prime, /* OUT */ |
| hb_blob_t **loca_prime /* OUT */) |
| { |
| hb_blob_t *glyf_blob = hb_sanitize_context_t ().reference_table<OT::glyf> (plan->source); |
| const char *glyf_data = hb_blob_get_data (glyf_blob, nullptr); |
| |
| OT::glyf::accelerator_t glyf; |
| glyf.init (plan->source); |
| bool result = _hb_subset_glyf_and_loca (glyf, |
| glyf_data, |
| plan, |
| use_short_loca, |
| glyf_prime, |
| loca_prime); |
| |
| hb_blob_destroy (glyf_blob); |
| glyf.fini (); |
| |
| return result; |
| } |
