127 lines
3.5 KiB
C++
127 lines
3.5 KiB
C++
#ifndef OT_LAYOUT_GSUB_ALTERNATESET_HH
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#define OT_LAYOUT_GSUB_ALTERNATESET_HH
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#include "Common.hh"
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namespace OT {
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namespace Layout {
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namespace GSUB_impl {
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template <typename Types>
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struct AlternateSet
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{
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protected:
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Array16Of<typename Types::HBGlyphID>
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alternates; /* Array of alternate GlyphIDs--in
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* arbitrary order */
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public:
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DEFINE_SIZE_ARRAY (2, alternates);
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bool sanitize (hb_sanitize_context_t *c) const
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{
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TRACE_SANITIZE (this);
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return_trace (alternates.sanitize (c));
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}
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bool intersects (const hb_set_t *glyphs) const
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{ return hb_any (alternates, glyphs); }
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void closure (hb_closure_context_t *c) const
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{ c->output->add_array (alternates.arrayZ, alternates.len); }
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void collect_glyphs (hb_collect_glyphs_context_t *c) const
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{ c->output->add_array (alternates.arrayZ, alternates.len); }
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bool apply (hb_ot_apply_context_t *c) const
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{
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TRACE_APPLY (this);
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unsigned int count = alternates.len;
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if (unlikely (!count)) return_trace (false);
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hb_mask_t glyph_mask = c->buffer->cur().mask;
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hb_mask_t lookup_mask = c->lookup_mask;
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/* Note: This breaks badly if two features enabled this lookup together. */
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unsigned int shift = hb_ctz (lookup_mask);
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unsigned int alt_index = ((lookup_mask & glyph_mask) >> shift);
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/* If alt_index is MAX_VALUE, randomize feature if it is the rand feature. */
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if (alt_index == HB_OT_MAP_MAX_VALUE && c->random)
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{
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/* Maybe we can do better than unsafe-to-break all; but since we are
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* changing random state, it would be hard to track that. Good 'nough. */
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c->buffer->unsafe_to_break (0, c->buffer->len);
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alt_index = c->random_number () % count + 1;
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}
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if (unlikely (alt_index > count || alt_index == 0)) return_trace (false);
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if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
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{
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c->buffer->sync_so_far ();
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c->buffer->message (c->font,
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"replacing glyph at %u (alternate substitution)",
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c->buffer->idx);
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}
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c->replace_glyph (alternates[alt_index - 1]);
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if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
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{
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c->buffer->message (c->font,
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"replaced glyph at %u (alternate substitution)",
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c->buffer->idx - 1u);
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}
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return_trace (true);
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}
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unsigned
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get_alternates (unsigned start_offset,
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unsigned *alternate_count /* IN/OUT. May be NULL. */,
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hb_codepoint_t *alternate_glyphs /* OUT. May be NULL. */) const
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{
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if (alternates.len && alternate_count)
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{
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+ alternates.as_array ().sub_array (start_offset, alternate_count)
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| hb_sink (hb_array (alternate_glyphs, *alternate_count))
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;
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}
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return alternates.len;
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}
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template <typename Iterator,
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hb_requires (hb_is_source_of (Iterator, hb_codepoint_t))>
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bool serialize (hb_serialize_context_t *c,
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Iterator alts)
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{
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TRACE_SERIALIZE (this);
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return_trace (alternates.serialize (c, alts));
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}
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bool subset (hb_subset_context_t *c) const
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{
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TRACE_SUBSET (this);
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const hb_set_t &glyphset = *c->plan->glyphset_gsub ();
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const hb_map_t &glyph_map = *c->plan->glyph_map;
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auto it =
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+ hb_iter (alternates)
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| hb_filter (glyphset)
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| hb_map (glyph_map)
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;
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auto *out = c->serializer->start_embed (*this);
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return_trace (out->serialize (c->serializer, it) &&
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out->alternates);
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}
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};
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}
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}
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}
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#endif /* OT_LAYOUT_GSUB_ALTERNATESET_HH */
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