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#ifndef OT_LAYOUT_GSUB_REVERSECHAINSINGLESUBSTFORMAT1_HH
#define OT_LAYOUT_GSUB_REVERSECHAINSINGLESUBSTFORMAT1_HH
#include "Common.hh"
namespace OT {
namespace Layout {
namespace GSUB_impl {
struct ReverseChainSingleSubstFormat1
{
protected:
HBUINT16 format; /* Format identifier--format = 1 */
Offset16To<Coverage>
coverage; /* Offset to Coverage table--from
* beginning of table */
Array16OfOffset16To<Coverage>
backtrack; /* Array of coverage tables
* in backtracking sequence, in glyph
* sequence order */
Array16OfOffset16To<Coverage>
lookaheadX; /* Array of coverage tables
* in lookahead sequence, in glyph
* sequence order */
Array16Of<HBGlyphID16>
substituteX; /* Array of substitute
* GlyphIDs--ordered by Coverage Index */
public:
DEFINE_SIZE_MIN (10);
bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
if (!(coverage.sanitize (c, this) && backtrack.sanitize (c, this)))
return_trace (false);
const auto &lookahead = StructAfter<decltype (lookaheadX)> (backtrack);
if (!lookahead.sanitize (c, this))
return_trace (false);
const auto &substitute = StructAfter<decltype (substituteX)> (lookahead);
return_trace (substitute.sanitize (c));
}
bool intersects (const hb_set_t *glyphs) const
{
if (!(this+coverage).intersects (glyphs))
return false;
const auto &lookahead = StructAfter<decltype (lookaheadX)> (backtrack);
unsigned int count;
count = backtrack.len;
for (unsigned int i = 0; i < count; i++)
if (!(this+backtrack[i]).intersects (glyphs))
return false;
count = lookahead.len;
for (unsigned int i = 0; i < count; i++)
if (!(this+lookahead[i]).intersects (glyphs))
return false;
return true;
}
bool may_have_non_1to1 () const
{ return false; }
void closure (hb_closure_context_t *c) const
{
if (!intersects (c->glyphs)) return;
const auto &lookahead = StructAfter<decltype (lookaheadX)> (backtrack);
const auto &substitute = StructAfter<decltype (substituteX)> (lookahead);
+ hb_zip (this+coverage, substitute)
| hb_filter (c->parent_active_glyphs (), hb_first)
| hb_map (hb_second)
| hb_sink (c->output)
;
}
void closure_lookups (hb_closure_lookups_context_t *c) const {}
void collect_glyphs (hb_collect_glyphs_context_t *c) const
{
if (unlikely (!(this+coverage).collect_coverage (c->input))) return;
unsigned int count;
count = backtrack.len;
for (unsigned int i = 0; i < count; i++)
if (unlikely (!(this+backtrack[i]).collect_coverage (c->before))) return;
const auto &lookahead = StructAfter<decltype (lookaheadX)> (backtrack);
count = lookahead.len;
for (unsigned int i = 0; i < count; i++)
if (unlikely (!(this+lookahead[i]).collect_coverage (c->after))) return;
const auto &substitute = StructAfter<decltype (substituteX)> (lookahead);
count = substitute.len;
c->output->add_array (substitute.arrayZ, substitute.len);
}
const Coverage &get_coverage () const { return this+coverage; }
bool would_apply (hb_would_apply_context_t *c) const
{ return c->len == 1 && (this+coverage).get_coverage (c->glyphs[0]) != NOT_COVERED; }
bool apply (hb_ot_apply_context_t *c) const
{
TRACE_APPLY (this);
if (unlikely (c->nesting_level_left != HB_MAX_NESTING_LEVEL))
return_trace (false); /* No chaining to this type */
unsigned int index = (this+coverage).get_coverage (c->buffer->cur ().codepoint);
if (likely (index == NOT_COVERED)) return_trace (false);
const auto &lookahead = StructAfter<decltype (lookaheadX)> (backtrack);
const auto &substitute = StructAfter<decltype (substituteX)> (lookahead);
if (unlikely (index >= substitute.len)) return_trace (false);
unsigned int start_index = 0, end_index = 0;
if (match_backtrack (c,
backtrack.len, (HBUINT16 *) backtrack.arrayZ,
match_coverage, this,
&start_index) &&
match_lookahead (c,
lookahead.len, (HBUINT16 *) lookahead.arrayZ,
match_coverage, this,
c->buffer->idx + 1, &end_index))
{
c->buffer->unsafe_to_break_from_outbuffer (start_index, end_index);
if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
{
c->buffer->message (c->font,
"replacing glyph at %u (reverse chaining substitution)",
c->buffer->idx);
}
c->replace_glyph_inplace (substitute[index]);
if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
{
c->buffer->message (c->font,
"replaced glyph at %u (reverse chaining substitution)",
c->buffer->idx);
}
/* Note: We DON'T decrease buffer->idx. The main loop does it
* for us. This is useful for preventing surprises if someone
* calls us through a Context lookup. */
return_trace (true);
}
else
{
c->buffer->unsafe_to_concat_from_outbuffer (start_index, end_index);
return_trace (false);
}
}
template<typename Iterator,
hb_requires (hb_is_iterator (Iterator))>
bool serialize_coverage_offset_array (hb_subset_context_t *c, Iterator it) const
{
TRACE_SERIALIZE (this);
auto *out = c->serializer->start_embed<Array16OfOffset16To<Coverage>> ();
if (unlikely (!c->serializer->allocate_size<HBUINT16> (HBUINT16::static_size)))
return_trace (false);
for (auto& offset : it) {
auto *o = out->serialize_append (c->serializer);
if (unlikely (!o) || !o->serialize_subset (c, offset, this))
return_trace (false);
}
return_trace (true);
}
template<typename Iterator, typename BacktrackIterator, typename LookaheadIterator,
hb_requires (hb_is_sorted_source_of (Iterator, hb_codepoint_pair_t)),
hb_requires (hb_is_iterator (BacktrackIterator)),
hb_requires (hb_is_iterator (LookaheadIterator))>
bool serialize (hb_subset_context_t *c,
Iterator coverage_subst_iter,
BacktrackIterator backtrack_iter,
LookaheadIterator lookahead_iter) const
{
TRACE_SERIALIZE (this);
auto *out = c->serializer->start_embed (this);
if (unlikely (!c->serializer->embed (this->format))) return_trace (false);
if (unlikely (!c->serializer->embed (this->coverage))) return_trace (false);
if (!serialize_coverage_offset_array (c, backtrack_iter)) return_trace (false);
if (!serialize_coverage_offset_array (c, lookahead_iter)) return_trace (false);
auto *substitute_out = c->serializer->start_embed<Array16Of<HBGlyphID16>> ();
auto substitutes =
+ coverage_subst_iter
| hb_map (hb_second)
;
auto glyphs =
+ coverage_subst_iter
| hb_map_retains_sorting (hb_first)
;
if (unlikely (! c->serializer->check_success (substitute_out->serialize (c->serializer, substitutes))))
return_trace (false);
if (unlikely (!out->coverage.serialize_serialize (c->serializer, glyphs)))
return_trace (false);
return_trace (true);
}
bool subset (hb_subset_context_t *c) const
{
TRACE_SUBSET (this);
const hb_set_t &glyphset = *c->plan->glyphset_gsub ();
const hb_map_t &glyph_map = *c->plan->glyph_map;
const auto &lookahead = StructAfter<decltype (lookaheadX)> (backtrack);
const auto &substitute = StructAfter<decltype (substituteX)> (lookahead);
auto it =
+ hb_zip (this+coverage, substitute)
| hb_filter (glyphset, hb_first)
| hb_filter (glyphset, hb_second)
| hb_map_retains_sorting ([&] (hb_pair_t<hb_codepoint_t, const HBGlyphID16 &> p) -> hb_codepoint_pair_t
{ return hb_pair (glyph_map[p.first], glyph_map[p.second]); })
;
return_trace (bool (it) && serialize (c, it, backtrack.iter (), lookahead.iter ()));
}
};
}
}
}
#endif /* HB_OT_LAYOUT_GSUB_REVERSECHAINSINGLESUBSTFORMAT1_HH */