311 lines
12 KiB
C++
311 lines
12 KiB
C++
/*
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* Copyright © 2018 Google, Inc.
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*
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* This is part of HarfBuzz, a text shaping library.
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*
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* Permission is hereby granted, without written agreement and without
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* license or royalty fees, to use, copy, modify, and distribute this
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* software and its documentation for any purpose, provided that the
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* above copyright notice and the following two paragraphs appear in
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* all copies of this software.
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*
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* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
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* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
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* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
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* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
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* DAMAGE.
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*
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* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
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* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
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* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
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* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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*
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* Google Author(s): Garret Rieger, Roderick Sheeter
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*/
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#include "hb-open-type.hh"
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#include "hb-ot-glyf-table.hh"
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#include "hb-set.h"
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#include "hb-subset-glyf.hh"
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static bool
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_calculate_glyf_and_loca_prime_size (const OT::glyf::accelerator_t &glyf,
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hb_vector_t<hb_codepoint_t> &glyph_ids,
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hb_bool_t drop_hints,
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bool *use_short_loca /* OUT */,
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unsigned int *glyf_size /* OUT */,
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unsigned int *loca_size /* OUT */,
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hb_vector_t<unsigned int> *instruction_ranges /* OUT */)
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{
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unsigned int total = 0;
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for (unsigned int i = 0; i < glyph_ids.len; i++)
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{
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hb_codepoint_t next_glyph = glyph_ids[i];
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if (!instruction_ranges->resize (instruction_ranges->len + 2))
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{
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DEBUG_MSG(SUBSET, nullptr, "Failed to resize instruction_ranges.");
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return false;
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}
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unsigned int *instruction_start = &(*instruction_ranges)[instruction_ranges->len - 2];
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*instruction_start = 0;
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unsigned int *instruction_end = &(*instruction_ranges)[instruction_ranges->len - 1];
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*instruction_end = 0;
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unsigned int start_offset, end_offset;
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if (unlikely (!(glyf.get_offsets(next_glyph, &start_offset, &end_offset)
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&& glyf.remove_padding(start_offset, &end_offset))))
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{
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DEBUG_MSG(SUBSET, nullptr, "Invalid gid %d", next_glyph);
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continue;
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}
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if (end_offset - start_offset < OT::glyf::GlyphHeader::static_size)
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continue; /* 0-length glyph */
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if (drop_hints)
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{
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if (unlikely (!glyf.get_instruction_offsets(start_offset, end_offset,
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instruction_start, instruction_end)))
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{
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DEBUG_MSG(SUBSET, nullptr, "Unable to get instruction offsets for %d", next_glyph);
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return false;
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}
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}
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total += end_offset - start_offset - (*instruction_end - *instruction_start);
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/* round2 so short loca will work */
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total += total % 2;
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}
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*glyf_size = total;
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*use_short_loca = (total <= 131070);
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*loca_size = (glyph_ids.len + 1)
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* (*use_short_loca ? sizeof(OT::HBUINT16) : sizeof(OT::HBUINT32));
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DEBUG_MSG(SUBSET, nullptr, "preparing to subset glyf: final size %d, loca size %d, using %s loca",
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total,
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*loca_size,
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*use_short_loca ? "short" : "long");
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return true;
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}
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static bool
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_write_loca_entry (unsigned int id,
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unsigned int offset,
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bool is_short,
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void *loca_prime,
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unsigned int loca_size)
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{
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unsigned int entry_size = is_short ? sizeof (OT::HBUINT16) : sizeof (OT::HBUINT32);
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if ((id + 1) * entry_size <= loca_size)
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{
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if (is_short) {
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((OT::HBUINT16*) loca_prime) [id].set (offset / 2);
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} else {
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((OT::HBUINT32*) loca_prime) [id].set (offset);
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}
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return true;
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}
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// Offset was not written because the write is out of bounds.
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DEBUG_MSG (SUBSET,
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nullptr,
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"WARNING: Attempted to write an out of bounds loca entry at index %d. Loca size is %d.",
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id,
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loca_size);
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return false;
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}
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static void
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_update_components (hb_subset_plan_t * plan,
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char * glyph_start,
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unsigned int length)
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{
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OT::glyf::CompositeGlyphHeader::Iterator iterator;
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if (OT::glyf::CompositeGlyphHeader::get_iterator (glyph_start,
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length,
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&iterator))
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{
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do
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{
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hb_codepoint_t new_gid;
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if (!plan->new_gid_for_old_gid (iterator.current->glyphIndex,
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&new_gid))
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continue;
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((OT::glyf::CompositeGlyphHeader *) iterator.current)->glyphIndex.set (new_gid);
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} while (iterator.move_to_next());
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}
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}
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static bool _remove_composite_instruction_flag(char *glyf_prime, unsigned int length)
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{
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/* remove WE_HAVE_INSTRUCTIONS from flags in dest */
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OT::glyf::CompositeGlyphHeader::Iterator composite_it;
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if (unlikely (!OT::glyf::CompositeGlyphHeader::get_iterator (glyf_prime, length, &composite_it))) return false;
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const OT::glyf::CompositeGlyphHeader *glyph;
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do {
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glyph = composite_it.current;
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OT::HBUINT16 *flags = const_cast<OT::HBUINT16 *> (&glyph->flags);
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flags->set ( (uint16_t) *flags & ~OT::glyf::CompositeGlyphHeader::WE_HAVE_INSTRUCTIONS);
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} while (composite_it.move_to_next());
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return true;
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}
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static bool
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_write_glyf_and_loca_prime (hb_subset_plan_t *plan,
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const OT::glyf::accelerator_t &glyf,
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const char *glyf_data,
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bool use_short_loca,
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hb_vector_t<unsigned int> &instruction_ranges,
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unsigned int glyf_prime_size,
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char *glyf_prime_data /* OUT */,
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unsigned int loca_prime_size,
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char *loca_prime_data /* OUT */)
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{
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hb_vector_t<hb_codepoint_t> &glyph_ids = plan->glyphs;
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char *glyf_prime_data_next = glyf_prime_data;
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bool success = true;
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for (unsigned int i = 0; i < glyph_ids.len; i++)
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{
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unsigned int start_offset, end_offset;
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if (unlikely (!(glyf.get_offsets (glyph_ids[i], &start_offset, &end_offset)
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&& glyf.remove_padding(start_offset, &end_offset))))
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end_offset = start_offset = 0;
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unsigned int instruction_start = instruction_ranges[i * 2];
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unsigned int instruction_end = instruction_ranges[i * 2 + 1];
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int length = end_offset - start_offset - (instruction_end - instruction_start);
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if (glyf_prime_data_next + length > glyf_prime_data + glyf_prime_size)
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{
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DEBUG_MSG (SUBSET,
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nullptr,
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"WARNING: Attempted to write an out of bounds glyph entry for gid %d (length %d)",
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i, length);
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return false;
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}
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if (instruction_start == instruction_end)
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memcpy (glyf_prime_data_next, glyf_data + start_offset, length);
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else
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{
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memcpy (glyf_prime_data_next, glyf_data + start_offset, instruction_start - start_offset);
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memcpy (glyf_prime_data_next + instruction_start - start_offset, glyf_data + instruction_end, end_offset - instruction_end);
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/* if the instructions end at the end this was a composite glyph, else simple */
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if (instruction_end == end_offset)
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{
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if (unlikely (!_remove_composite_instruction_flag (glyf_prime_data_next, length))) return false;
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}
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else
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/* zero instruction length, which is just before instruction_start */
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memset (glyf_prime_data_next + instruction_start - start_offset - 2, 0, 2);
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}
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success = success && _write_loca_entry (i,
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glyf_prime_data_next - glyf_prime_data,
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use_short_loca,
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loca_prime_data,
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loca_prime_size);
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_update_components (plan, glyf_prime_data_next, length);
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// TODO: don't align to two bytes if using long loca.
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glyf_prime_data_next += length + (length % 2); // Align to 2 bytes for short loca.
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}
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success = success && _write_loca_entry (glyph_ids.len,
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glyf_prime_data_next - glyf_prime_data,
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use_short_loca,
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loca_prime_data,
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loca_prime_size);
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return success;
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}
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static bool
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_hb_subset_glyf_and_loca (const OT::glyf::accelerator_t &glyf,
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const char *glyf_data,
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hb_subset_plan_t *plan,
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bool *use_short_loca,
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hb_blob_t **glyf_prime /* OUT */,
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hb_blob_t **loca_prime /* OUT */)
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{
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// TODO(grieger): Sanity check allocation size for the new table.
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hb_vector_t<hb_codepoint_t> &glyphs_to_retain = plan->glyphs;
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unsigned int glyf_prime_size;
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unsigned int loca_prime_size;
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hb_vector_t<unsigned int> instruction_ranges;
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instruction_ranges.init();
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if (unlikely (!_calculate_glyf_and_loca_prime_size (glyf,
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glyphs_to_retain,
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plan->drop_hints,
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use_short_loca,
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&glyf_prime_size,
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&loca_prime_size,
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&instruction_ranges))) {
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instruction_ranges.fini();
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return false;
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}
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char *glyf_prime_data = (char *) calloc (1, glyf_prime_size);
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char *loca_prime_data = (char *) calloc (1, loca_prime_size);
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if (unlikely (!_write_glyf_and_loca_prime (plan, glyf, glyf_data,
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*use_short_loca,
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instruction_ranges,
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glyf_prime_size, glyf_prime_data,
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loca_prime_size, loca_prime_data))) {
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free (glyf_prime_data);
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free (loca_prime_data);
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instruction_ranges.fini();
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return false;
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}
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instruction_ranges.fini();
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*glyf_prime = hb_blob_create (glyf_prime_data,
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glyf_prime_size,
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HB_MEMORY_MODE_READONLY,
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glyf_prime_data,
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free);
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*loca_prime = hb_blob_create (loca_prime_data,
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loca_prime_size,
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HB_MEMORY_MODE_READONLY,
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loca_prime_data,
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free);
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return true;
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}
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/**
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* hb_subset_glyf:
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* Subsets the glyph table according to a provided plan.
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*
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* Return value: subsetted glyf table.
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*
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* Since: 1.7.5
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**/
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bool
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hb_subset_glyf_and_loca (hb_subset_plan_t *plan,
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bool *use_short_loca, /* OUT */
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hb_blob_t **glyf_prime, /* OUT */
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hb_blob_t **loca_prime /* OUT */)
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{
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hb_blob_t *glyf_blob = hb_sanitize_context_t ().reference_table<OT::glyf> (plan->source);
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const char *glyf_data = hb_blob_get_data(glyf_blob, nullptr);
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OT::glyf::accelerator_t glyf;
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glyf.init(plan->source);
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bool result = _hb_subset_glyf_and_loca (glyf,
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glyf_data,
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plan,
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use_short_loca,
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glyf_prime,
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loca_prime);
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hb_blob_destroy (glyf_blob);
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glyf.fini();
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return result;
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}
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