| /* |
| * 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" |
| |
| bool |
| _calculate_glyf_and_loca_prime_size (const OT::glyf::accelerator_t &glyf, |
| hb_auto_array_t<unsigned int> &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))) { |
| *glyf_size = 0; |
| *loca_size = sizeof(OT::HBUINT32); |
| return false; |
| } |
| |
| 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; |
| } |
| |
| void |
| _write_loca_entry (unsigned int id, unsigned int offset, bool is_short, void *loca_prime) { |
| if (is_short) { |
| ((OT::HBUINT16*) loca_prime) [id].set (offset / 2); |
| } else { |
| ((OT::HBUINT32*) loca_prime) [id].set (offset); |
| } |
| } |
| |
| bool |
| _write_glyf_and_loca_prime (const OT::glyf::accelerator_t &glyf, |
| const char *glyf_data, |
| hb_auto_array_t<unsigned int> &glyph_ids, |
| bool use_short_loca, |
| int glyf_prime_size, |
| char *glyf_prime_data /* OUT */, |
| int loca_prime_size, |
| char *loca_prime_data /* OUT */) |
| { |
| char *glyf_prime_data_next = glyf_prime_data; |
| |
| hb_codepoint_t next_glyph = -1; |
| hb_codepoint_t new_glyph_id = 0; |
| |
| unsigned int end_offset; |
| for (unsigned int i = 0; i < glyph_ids.len; i++) { |
| unsigned int start_offset; |
| if (unlikely (!glyf.get_offsets (glyph_ids[i], &start_offset, &end_offset))) { |
| return false; |
| } |
| |
| int length = end_offset - start_offset; |
| memcpy (glyf_prime_data_next, glyf_data + start_offset, length); |
| |
| _write_loca_entry (i, start_offset, use_short_loca, loca_prime_data); |
| |
| glyf_prime_data_next += length; |
| new_glyph_id++; |
| } |
| |
| // Add the last loca entry which doesn't correspond to a specific glyph |
| // but identifies the end of the last glyphs data. |
| _write_loca_entry (new_glyph_id, end_offset, use_short_loca, loca_prime_data); |
| |
| return true; |
| } |
| |
| bool |
| _hb_subset_glyf_and_loca (const OT::glyf::accelerator_t &glyf, |
| const char *glyf_data, |
| hb_auto_array_t<unsigned int> &glyphs_to_retain, |
| bool *use_short_loca, |
| hb_blob_t **glyf_prime /* OUT */, |
| hb_blob_t **loca_prime /* OUT */) |
| { |
| // TODO(grieger): Sanity check writes to make sure they are in-bounds. |
| // TODO(grieger): Sanity check allocation size for the new table. |
| // TODO(grieger): Don't fail on bad offsets, just dump them. |
| |
| 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 *) calloc (glyf_prime_size, 1); |
| char *loca_prime_data = (char *) calloc (loca_prime_size, 1); |
| if (unlikely (!_write_glyf_and_loca_prime (glyf, glyf_data, glyphs_to_retain, |
| *use_short_loca, |
| glyf_prime_size, glyf_prime_data, |
| loca_prime_size, loca_prime_data))) { |
| free (glyf_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, |
| hb_face_t *face, |
| bool *use_short_loca, /* OUT */ |
| hb_blob_t **glyf_prime, /* OUT */ |
| hb_blob_t **loca_prime /* OUT */) |
| { |
| hb_blob_t *glyf_blob = OT::Sanitizer<OT::glyf>().sanitize (face->reference_table (HB_OT_TAG_glyf)); |
| const char *glyf_data = hb_blob_get_data(glyf_blob, nullptr); |
| |
| OT::glyf::accelerator_t glyf; |
| glyf.init(face); |
| bool result = _hb_subset_glyf_and_loca (glyf, |
| glyf_data, |
| plan->gids_to_retain_sorted, |
| use_short_loca, |
| glyf_prime, |
| loca_prime); |
| glyf.fini(); |
| |
| *use_short_loca = false; |
| |
| return result; |
| } |
