347 lines
12 KiB
C++
347 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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struct loca_data_t
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{
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bool is_short;
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void *data;
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unsigned int size;
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inline bool
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_write_loca_entry (unsigned int id,
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unsigned int offset)
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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 <= size)
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{
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if (is_short) {
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((OT::HBUINT16*) data) [id] = offset / 2;
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} else {
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((OT::HBUINT32*) data) [id] = 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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size);
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return false;
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}
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};
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/*
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* If hints are being dropped find the range which in glyf at which
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* the hinting instructions are located. Add them to the instruction_ranges
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* vector.
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*/
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static bool
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_add_instructions_range (const OT::glyf::accelerator_t &glyf,
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hb_codepoint_t glyph_id,
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unsigned int glyph_start_offset,
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unsigned int glyph_end_offset,
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bool drop_hints,
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hb_vector_t<unsigned int> *instruction_ranges /* OUT */)
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{
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if (!instruction_ranges->resize (instruction_ranges->length + 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->length - 2];
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*instruction_start = 0;
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unsigned int *instruction_end = &(*instruction_ranges)[instruction_ranges->length - 1];
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*instruction_end = 0;
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if (drop_hints)
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{
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if (unlikely (!glyf.get_instruction_offsets (glyph_start_offset, glyph_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", glyph_id);
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return false;
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}
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}
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return true;
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}
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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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const hb_subset_plan_t *plan,
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loca_data_t *loca_data, /* OUT */
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unsigned int *glyf_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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hb_codepoint_t next_glyph = HB_SET_VALUE_INVALID;
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while (plan->glyphset ()->next (&next_glyph))
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{
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unsigned int start_offset = 0, end_offset = 0;
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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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start_offset = end_offset = 0;
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}
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bool is_zero_length = end_offset - start_offset < OT::glyf::GlyphHeader::static_size;
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if (!_add_instructions_range (glyf,
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next_glyph,
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start_offset,
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end_offset,
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plan->drop_hints && !is_zero_length,
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instruction_ranges))
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return false;
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if (is_zero_length)
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continue; /* 0-length glyph */
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total += end_offset - start_offset
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- ((*instruction_ranges)[instruction_ranges->length - 1]
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- (*instruction_ranges)[instruction_ranges->length - 2]);
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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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loca_data->is_short = (total <= 131070);
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loca_data->size = (plan->num_output_glyphs () + 1)
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* (loca_data->is_short ? 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_data->size,
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loca_data->is_short ? "short" : "long");
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return true;
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}
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static void
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_update_components (const 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 = 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 = (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 (const 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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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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loca_data_t *loca_prime /* OUT */)
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{
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char *glyf_prime_data_next = glyf_prime_data;
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bool success = true;
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unsigned int i = 0;
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hb_codepoint_t new_gid;
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for (new_gid = 0; new_gid < plan->num_output_glyphs (); new_gid++)
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{
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hb_codepoint_t old_gid;
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if (!plan->old_gid_for_new_gid (new_gid, &old_gid))
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{
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// Empty glyph, add a loca entry and carry on.
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loca_prime->_write_loca_entry (new_gid,
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glyf_prime_data_next - glyf_prime_data);
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continue;
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}
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unsigned int start_offset = 0, end_offset = 0;
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if (unlikely (!(glyf.get_offsets (old_gid, &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 && loca_prime->_write_loca_entry (new_gid,
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glyf_prime_data_next - glyf_prime_data);
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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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i++;
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}
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// loca table has n+1 entries where the last entry signifies the end location of the last
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// glyph.
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success = success && loca_prime->_write_loca_entry (new_gid,
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glyf_prime_data_next - glyf_prime_data);
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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_blob /* OUT */,
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hb_blob_t **loca_prime_blob /* OUT */)
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{
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// TODO(grieger): Sanity check allocation size for the new table.
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loca_data_t loca_prime;
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unsigned int glyf_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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plan,
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&loca_prime,
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&glyf_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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*use_short_loca = loca_prime.is_short;
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char *glyf_prime_data = (char *) calloc (1, glyf_prime_size);
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loca_prime.data = (void *) calloc (1, loca_prime.size);
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if (unlikely (!_write_glyf_and_loca_prime (plan, glyf, glyf_data,
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instruction_ranges,
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glyf_prime_size, glyf_prime_data,
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&loca_prime))) {
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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_blob = 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_blob = hb_blob_create ((char *) 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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