[subset] Do some refactoring in hb-subset-glyf.cc.
- Extract code out into helper methods in several places. - Bundle loca address, size and is short into a struct.
This commit is contained in:
Garret Rieger
parent
b7f971884e
commit
4b1ac3a2fa
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@ -29,23 +29,65 @@
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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].set (offset / 2);
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} else {
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((OT::HBUINT32*) data) [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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size);
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return false;
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}
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inline bool
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_add_empty_glyphs_to_loca (hb_codepoint_t from_gid,
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hb_codepoint_t to_gid,
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unsigned int offset)
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{
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bool success = true;
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while (from_gid < to_gid)
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{
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success = success && _write_loca_entry (from_gid,
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offset);
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from_gid++;
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}
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return success;
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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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_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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const hb_map_t *glyph_map,
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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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_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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unsigned int total = 0;
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hb_codepoint_t max_new_gid = 0;
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for (unsigned int i = 0; i < glyph_ids.length; i++)
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{
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hb_codepoint_t next_glyph = glyph_ids[i];
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hb_codepoint_t next_glyph_new_gid = glyph_map->get (next_glyph);
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max_new_gid = MAX (max_new_gid, next_glyph_new_gid);
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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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@ -56,6 +98,35 @@ _calculate_glyf_and_loca_prime_size (const OT::glyf::accelerator_t &glyf,
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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 max_new_gid = 0;
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for (unsigned int i = 0; i < plan->glyphs.length; i++)
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{
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hb_codepoint_t next_glyph = plan->glyphs[i];
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hb_codepoint_t new_gid_for_next_glyph;
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if (plan->new_gid_for_old_gid (next_glyph, &new_gid_for_next_glyph))
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max_new_gid = MAX (max_new_gid, new_gid_for_next_glyph);
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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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@ -63,63 +134,38 @@ _calculate_glyf_and_loca_prime_size (const OT::glyf::accelerator_t &glyf,
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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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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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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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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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*use_short_loca = (total <= 131070);
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*loca_size = (max_new_gid + 2)
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* (*use_short_loca ? sizeof (OT::HBUINT16) : sizeof (OT::HBUINT32));
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loca_data->is_short = (total <= 131070);
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loca_data->size = (max_new_gid + 2)
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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_size,
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*use_short_loca ? "short" : "long");
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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 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 (const hb_subset_plan_t *plan,
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char *glyph_start,
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@ -160,33 +206,28 @@ 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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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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loca_data_t *loca_prime /* OUT */)
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{
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const hb_vector_t<hb_codepoint_t> &glyph_ids = plan->glyphs;
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const hb_map_t *glyph_map = plan->glyph_map;
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char *glyf_prime_data_next = glyf_prime_data;
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bool success = true;
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hb_codepoint_t gid = 0;
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unsigned int current_gid = 0;
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for (unsigned int i = 0; i < glyph_ids.length; i++)
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{
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while (gid < glyph_map->get (glyph_ids[i]))
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{
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hb_codepoint_t next_gid = current_gid;
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success = success && plan->new_gid_for_old_gid (glyph_ids[i], &next_gid);
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// If we are retaining existing gids then there will potentially be gaps
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// in the loca table between glyphs. Fill in this gap with glyphs that have
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// no outlines.
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success = success && _write_loca_entry (gid,
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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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gid++;
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}
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success = success && loca_prime->_add_empty_glyphs_to_loca (current_gid,
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next_gid,
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glyf_prime_data_next - glyf_prime_data);
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current_gid = next_gid;
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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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@ -223,23 +264,19 @@ _write_glyf_and_loca_prime (const hb_subset_plan_t *plan,
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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 (gid,
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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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success = success && loca_prime->_write_loca_entry (current_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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gid++;
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current_gid++;
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}
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success = success && _write_loca_entry (gid,
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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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// 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 (current_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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@ -248,52 +285,47 @@ _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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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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hb_vector_t<hb_codepoint_t> &glyphs_to_retain = plan->glyphs;
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loca_data_t loca_prime;
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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->glyph_map,
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plan->drop_hints,
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use_short_loca,
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plan,
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&loca_prime,
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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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*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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char *loca_prime_data = (char *) calloc (1, loca_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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*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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&loca_prime))) {
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free (glyf_prime_data);
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free (loca_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_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 = hb_blob_create (loca_prime_data,
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loca_prime_size,
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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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loca_prime.data,
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free);
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return true;
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}
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