/* * 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 */ #include "hb-open-type-private.hh" #include "hb-ot-glyf-table.hh" #include "hb-set.h" #include "hb-subset-glyf.hh" #include "hb-subset-plan.hh" static bool _calculate_glyf_and_loca_prime_size (const OT::glyf::accelerator_t &glyf, hb_prealloced_array_t &glyph_ids, bool *use_short_loca, /* OUT */ unsigned int *glyf_size, /* OUT */ unsigned int *loca_size /* OUT */) { unsigned int total = 0; unsigned int count = 0; for (unsigned int i = 0; i < glyph_ids.len; i++) { hb_codepoint_t next_glyph = glyph_ids[i]; unsigned int start_offset, end_offset; if (unlikely (!glyf.get_offsets (next_glyph, &start_offset, &end_offset))) end_offset = start_offset = 0; total += end_offset - start_offset; count++; } *glyf_size = total; *use_short_loca = (total <= 131070); *loca_size = (count + 1) * (*use_short_loca ? 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_size, *use_short_loca ? "short" : "long"); return true; } static bool _write_loca_entry (unsigned int id, unsigned int offset, bool is_short, void *loca_prime, unsigned int loca_size) { unsigned int entry_size = is_short ? sizeof (OT::HBUINT16) : sizeof (OT::HBUINT32); if ((id + 1) * entry_size <= loca_size) { if (is_short) { ((OT::HBUINT16*) loca_prime) [id].set (offset / 2); } else { ((OT::HBUINT32*) loca_prime) [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, loca_size); return false; } static void _update_components (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 (!hb_subset_plan_new_gid_for_old_id (plan, iterator.current->glyphIndex, &new_gid)) continue; ((OT::glyf::CompositeGlyphHeader *) iterator.current)->glyphIndex.set (new_gid); } while (iterator.move_to_next()); } } static bool _write_glyf_and_loca_prime (hb_subset_plan_t *plan, const OT::glyf::accelerator_t &glyf, const char *glyf_data, bool use_short_loca, unsigned int glyf_prime_size, char *glyf_prime_data /* OUT */, unsigned int loca_prime_size, char *loca_prime_data /* OUT */) { // TODO(grieger): Sanity check writes to make sure they are in-bounds. hb_prealloced_array_t &glyph_ids = plan->gids_to_retain_sorted; char *glyf_prime_data_next = glyf_prime_data; bool success = true; for (unsigned int i = 0; i < glyph_ids.len; i++) { unsigned int start_offset, end_offset; if (unlikely (!glyf.get_offsets (glyph_ids[i], &start_offset, &end_offset))) end_offset = start_offset = 0; int length = end_offset - start_offset; memcpy (glyf_prime_data_next, glyf_data + start_offset, length); success = success && _write_loca_entry (i, glyf_prime_data_next - glyf_prime_data, use_short_loca, loca_prime_data, loca_prime_size); _update_components (plan, glyf_prime_data_next, end_offset - start_offset); glyf_prime_data_next += length; } success = success && _write_loca_entry (glyph_ids.len, glyf_prime_data_next - glyf_prime_data, use_short_loca, loca_prime_data, loca_prime_size); 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 /* OUT */, hb_blob_t **loca_prime /* OUT */) { // TODO(grieger): Sanity check allocation size for the new table. hb_prealloced_array_t &glyphs_to_retain = plan->gids_to_retain_sorted; unsigned int glyf_prime_size; unsigned int loca_prime_size; if (unlikely (!_calculate_glyf_and_loca_prime_size (glyf, glyphs_to_retain, use_short_loca, &glyf_prime_size, &loca_prime_size))) { return false; } char *glyf_prime_data = (char *) malloc (glyf_prime_size); char *loca_prime_data = (char *) malloc (loca_prime_size); if (unlikely (!_write_glyf_and_loca_prime (plan, glyf, glyf_data, *use_short_loca, glyf_prime_size, glyf_prime_data, loca_prime_size, loca_prime_data))) { free (glyf_prime_data); free (loca_prime_data); return false; } *glyf_prime = hb_blob_create (glyf_prime_data, glyf_prime_size, HB_MEMORY_MODE_READONLY, glyf_prime_data, free); *loca_prime = hb_blob_create (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 = OT::Sanitizer().sanitize (plan->source->reference_table (HB_OT_TAG_glyf)); 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); glyf.fini(); return result; }