/* * Copyright © 2007,2008,2009,2010 Red Hat, Inc. * Copyright © 2010,2012 Google, Inc. * * This is part of HarfBuzz, a text shaping library. * * Permission is hereby granted, without written agreement and without * license or royalty fees, to use, copy, modify, and distribute this * software and its documentation for any purpose, provided that the * above copyright notice and the following two paragraphs appear in * all copies of this software. * * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH * DAMAGE. * * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. * * Red Hat Author(s): Behdad Esfahbod * Google Author(s): Behdad Esfahbod */ #ifndef HB_OT_LAYOUT_GSUB_TABLE_HH #define HB_OT_LAYOUT_GSUB_TABLE_HH #include "hb-ot-layout-gsubgpos-private.hh" struct SingleSubstFormat1 { friend struct SingleSubst; private: inline void closure (hb_closure_context_t *c) const { TRACE_CLOSURE (); Coverage::Iter iter; for (iter.init (this+coverage); iter.more (); iter.next ()) { hb_codepoint_t glyph_id = iter.get_glyph (); if (c->glyphs->has (glyph_id)) c->glyphs->add ((glyph_id + deltaGlyphID) & 0xFFFF); } } inline const Coverage &get_coverage (void) const { return this+coverage; } inline bool apply (hb_apply_context_t *c) const { TRACE_APPLY (); hb_codepoint_t glyph_id = c->buffer->cur().codepoint; unsigned int index = (this+coverage) (glyph_id); if (likely (index == NOT_COVERED)) return TRACE_RETURN (false); /* According to the Adobe Annotated OpenType Suite, result is always * limited to 16bit. */ glyph_id = (glyph_id + deltaGlyphID) & 0xFFFF; c->replace_glyph (glyph_id); return TRACE_RETURN (true); } inline bool sanitize (hb_sanitize_context_t *c) { TRACE_SANITIZE (); return TRACE_RETURN (coverage.sanitize (c, this) && deltaGlyphID.sanitize (c)); } protected: USHORT format; /* Format identifier--format = 1 */ OffsetTo coverage; /* Offset to Coverage table--from * beginning of Substitution table */ SHORT deltaGlyphID; /* Add to original GlyphID to get * substitute GlyphID */ public: DEFINE_SIZE_STATIC (6); }; struct SingleSubstFormat2 { friend struct SingleSubst; private: inline void closure (hb_closure_context_t *c) const { TRACE_CLOSURE (); Coverage::Iter iter; for (iter.init (this+coverage); iter.more (); iter.next ()) { if (c->glyphs->has (iter.get_glyph ())) c->glyphs->add (substitute[iter.get_coverage ()]); } } inline const Coverage &get_coverage (void) const { return this+coverage; } inline bool apply (hb_apply_context_t *c) const { TRACE_APPLY (); hb_codepoint_t glyph_id = c->buffer->cur().codepoint; unsigned int index = (this+coverage) (glyph_id); if (likely (index == NOT_COVERED)) return TRACE_RETURN (false); if (unlikely (index >= substitute.len)) return TRACE_RETURN (false); glyph_id = substitute[index]; c->replace_glyph (glyph_id); return TRACE_RETURN (true); } inline bool sanitize (hb_sanitize_context_t *c) { TRACE_SANITIZE (); return TRACE_RETURN (coverage.sanitize (c, this) && substitute.sanitize (c)); } protected: USHORT format; /* Format identifier--format = 2 */ OffsetTo coverage; /* Offset to Coverage table--from * beginning of Substitution table */ ArrayOf substitute; /* Array of substitute * GlyphIDs--ordered by Coverage Index */ public: DEFINE_SIZE_ARRAY (6, substitute); }; struct SingleSubst { friend struct SubstLookupSubTable; private: inline void closure (hb_closure_context_t *c) const { TRACE_CLOSURE (); switch (u.format) { case 1: u.format1.closure (c); break; case 2: u.format2.closure (c); break; default: break; } } inline const Coverage &get_coverage (void) const { switch (u.format) { case 1: return u.format1.get_coverage (); case 2: return u.format2.get_coverage (); default:return Null(Coverage); } } inline bool apply (hb_apply_context_t *c) const { TRACE_APPLY (); switch (u.format) { case 1: return TRACE_RETURN (u.format1.apply (c)); case 2: return TRACE_RETURN (u.format2.apply (c)); default:return TRACE_RETURN (false); } } inline bool sanitize (hb_sanitize_context_t *c) { TRACE_SANITIZE (); if (!u.format.sanitize (c)) return TRACE_RETURN (false); switch (u.format) { case 1: return TRACE_RETURN (u.format1.sanitize (c)); case 2: return TRACE_RETURN (u.format2.sanitize (c)); default:return TRACE_RETURN (true); } } protected: union { USHORT format; /* Format identifier */ SingleSubstFormat1 format1; SingleSubstFormat2 format2; } u; }; struct Sequence { friend struct MultipleSubstFormat1; private: inline void closure (hb_closure_context_t *c) const { TRACE_CLOSURE (); unsigned int count = substitute.len; for (unsigned int i = 0; i < count; i++) c->glyphs->add (substitute[i]); } inline bool apply (hb_apply_context_t *c) const { TRACE_APPLY (); if (unlikely (!substitute.len)) return TRACE_RETURN (false); unsigned int klass = c->property & HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE ? HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH : 0; unsigned int count = substitute.len; for (unsigned int i = 0; i < count; i++) { set_lig_props_for_component (c->buffer->cur(), i); c->output_glyph (substitute.array[i], klass); } c->buffer->skip_glyph (); return TRACE_RETURN (true); } public: inline bool sanitize (hb_sanitize_context_t *c) { TRACE_SANITIZE (); return TRACE_RETURN (substitute.sanitize (c)); } protected: ArrayOf substitute; /* String of GlyphIDs to substitute */ public: DEFINE_SIZE_ARRAY (2, substitute); }; struct MultipleSubstFormat1 { friend struct MultipleSubst; private: inline void closure (hb_closure_context_t *c) const { TRACE_CLOSURE (); Coverage::Iter iter; for (iter.init (this+coverage); iter.more (); iter.next ()) { if (c->glyphs->has (iter.get_glyph ())) (this+sequence[iter.get_coverage ()]).closure (c); } } inline const Coverage &get_coverage (void) const { return this+coverage; } inline bool apply (hb_apply_context_t *c) const { TRACE_APPLY (); unsigned int index = (this+coverage) (c->buffer->cur().codepoint); if (likely (index == NOT_COVERED)) return TRACE_RETURN (false); return TRACE_RETURN ((this+sequence[index]).apply (c)); } inline bool sanitize (hb_sanitize_context_t *c) { TRACE_SANITIZE (); return TRACE_RETURN (coverage.sanitize (c, this) && sequence.sanitize (c, this)); } protected: USHORT format; /* Format identifier--format = 1 */ OffsetTo coverage; /* Offset to Coverage table--from * beginning of Substitution table */ OffsetArrayOf sequence; /* Array of Sequence tables * ordered by Coverage Index */ public: DEFINE_SIZE_ARRAY (6, sequence); }; struct MultipleSubst { friend struct SubstLookupSubTable; private: inline void closure (hb_closure_context_t *c) const { TRACE_CLOSURE (); switch (u.format) { case 1: u.format1.closure (c); break; default: break; } } inline const Coverage &get_coverage (void) const { switch (u.format) { case 1: return u.format1.get_coverage (); default:return Null(Coverage); } } inline bool apply (hb_apply_context_t *c) const { TRACE_APPLY (); switch (u.format) { case 1: return TRACE_RETURN (u.format1.apply (c)); default:return TRACE_RETURN (false); } } inline bool sanitize (hb_sanitize_context_t *c) { TRACE_SANITIZE (); if (!u.format.sanitize (c)) return TRACE_RETURN (false); switch (u.format) { case 1: return TRACE_RETURN (u.format1.sanitize (c)); default:return TRACE_RETURN (true); } } protected: union { USHORT format; /* Format identifier */ MultipleSubstFormat1 format1; } u; }; typedef ArrayOf AlternateSet; /* Array of alternate GlyphIDs--in * arbitrary order */ struct AlternateSubstFormat1 { friend struct AlternateSubst; private: inline void closure (hb_closure_context_t *c) const { TRACE_CLOSURE (); Coverage::Iter iter; for (iter.init (this+coverage); iter.more (); iter.next ()) { if (c->glyphs->has (iter.get_glyph ())) { const AlternateSet &alt_set = this+alternateSet[iter.get_coverage ()]; unsigned int count = alt_set.len; for (unsigned int i = 0; i < count; i++) c->glyphs->add (alt_set[i]); } } } inline const Coverage &get_coverage (void) const { return this+coverage; } inline bool apply (hb_apply_context_t *c) const { TRACE_APPLY (); hb_codepoint_t glyph_id = c->buffer->cur().codepoint; unsigned int index = (this+coverage) (glyph_id); if (likely (index == NOT_COVERED)) return TRACE_RETURN (false); const AlternateSet &alt_set = this+alternateSet[index]; if (unlikely (!alt_set.len)) return TRACE_RETURN (false); hb_mask_t glyph_mask = c->buffer->cur().mask; hb_mask_t lookup_mask = c->lookup_mask; /* Note: This breaks badly if two features enabled this lookup together. */ unsigned int shift = _hb_ctz (lookup_mask); unsigned int alt_index = ((lookup_mask & glyph_mask) >> shift); if (unlikely (alt_index > alt_set.len || alt_index == 0)) return TRACE_RETURN (false); glyph_id = alt_set[alt_index - 1]; c->replace_glyph (glyph_id); return TRACE_RETURN (true); } inline bool sanitize (hb_sanitize_context_t *c) { TRACE_SANITIZE (); return TRACE_RETURN (coverage.sanitize (c, this) && alternateSet.sanitize (c, this)); } protected: USHORT format; /* Format identifier--format = 1 */ OffsetTo coverage; /* Offset to Coverage table--from * beginning of Substitution table */ OffsetArrayOf alternateSet; /* Array of AlternateSet tables * ordered by Coverage Index */ public: DEFINE_SIZE_ARRAY (6, alternateSet); }; struct AlternateSubst { friend struct SubstLookupSubTable; private: inline void closure (hb_closure_context_t *c) const { TRACE_CLOSURE (); switch (u.format) { case 1: u.format1.closure (c); break; default: break; } } inline const Coverage &get_coverage (void) const { switch (u.format) { case 1: return u.format1.get_coverage (); default:return Null(Coverage); } } inline bool apply (hb_apply_context_t *c) const { TRACE_APPLY (); switch (u.format) { case 1: return TRACE_RETURN (u.format1.apply (c)); default:return TRACE_RETURN (false); } } inline bool sanitize (hb_sanitize_context_t *c) { TRACE_SANITIZE (); if (!u.format.sanitize (c)) return TRACE_RETURN (false); switch (u.format) { case 1: return TRACE_RETURN (u.format1.sanitize (c)); default:return TRACE_RETURN (true); } } protected: union { USHORT format; /* Format identifier */ AlternateSubstFormat1 format1; } u; }; struct Ligature { friend struct LigatureSet; private: inline void closure (hb_closure_context_t *c) const { TRACE_CLOSURE (); unsigned int count = component.len; for (unsigned int i = 1; i < count; i++) if (!c->glyphs->has (component[i])) return; c->glyphs->add (ligGlyph); } inline bool would_apply (hb_would_apply_context_t *c) const { return c->len == 1 || (c->len == 2 && component.len == 2 && component[1] == c->second); } inline bool apply (hb_apply_context_t *c) const { TRACE_APPLY (); unsigned int count = component.len; if (unlikely (count < 1)) return TRACE_RETURN (false); hb_apply_context_t::mark_skipping_forward_iterator_t skippy_iter (c, c->buffer->idx, count - 1); if (skippy_iter.has_no_chance ()) return TRACE_RETURN (false); /* * This is perhaps the trickiest part of GSUB... Remarks: * * - If all components of the ligature were marks, we call this a mark ligature. * * - If there is no GDEF, and the ligature is NOT a mark ligature, we categorize * it as a ligature glyph. Though, really, this will not really be used... * * - If it *is* a mark ligature, we don't allocate a new ligature id, and leave * the ligature to keep its old ligature id. This will allow it to attach to * a base ligature in GPOS. Eg. if the sequence is: LAM,LAM,SHADDA,FATHA,HEH, * and LAM,LAM,HEH for a ligature, they will leave SHADDA and FATHA wit a * ligature id and component value of 2. Then if SHADDA,FATHA form a ligature * later, we don't want them to lose their ligature id/component, otherwise * GPOS will fail to correctly position the mark ligature on top of the * LAM,LAM,HEH ligature. See: * https://bugzilla.gnome.org/show_bug.cgi?id=676343 * * - If a ligature is formed of components that some of which are also ligatures * themselves, and those ligature components had marks attached to *their* * components, we have to attach the marks to the new ligature component * positions! Now *that*'s tricky! And these marks may be following the * last component of the whole sequence, so we should loop forward looking * for them and update them. * * Eg. the sequence is LAM,LAM,SHADDA,FATHA,HEH, and the font first forms a * 'calt' ligature of LAM,HEH, leaving the SHADDA and FATHA with a ligature * id and component == 1. Now, during 'liga', the LAM and the LAM-HEH ligature * form a LAM-LAM-HEH ligature. We need to reassign the SHADDA and FATHA to * the new ligature with a component value of 2. * * This in fact happened to a font... See: * https://bugzilla.gnome.org/show_bug.cgi?id=437633 * * - Ligatures cannot be formed across glyphs attached to different components * of previous ligatures. Eg. the sequence is LAM,SHADDA,LAM,FATHA,HEH, and * LAM,LAM,HEH form a ligature, leaving SHADDA,FATHA next to eachother. * However, it would be wrong to ligate that SHADDA,FATHA sequence.o * There is an exception to this: If a ligature tries ligating with marks that * belong to it itself, go ahead, assuming that the font designer knows what * they are doing (otherwise it can break Indic stuff when a matra wants to * ligate with a conjunct...) */ bool is_mark_ligature = !!(c->property & HB_OT_LAYOUT_GLYPH_CLASS_MARK); unsigned int total_component_count = 0; total_component_count += get_lig_num_comps (c->buffer->cur()); unsigned int first_lig_id = get_lig_id (c->buffer->cur()); unsigned int first_lig_comp = get_lig_comp (c->buffer->cur()); for (unsigned int i = 1; i < count; i++) { unsigned int property; if (!skippy_iter.next (&property)) return TRACE_RETURN (false); if (likely (c->buffer->info[skippy_iter.idx].codepoint != component[i])) return TRACE_RETURN (false); unsigned int this_lig_id = get_lig_id (c->buffer->info[skippy_iter.idx]); unsigned int this_lig_comp = get_lig_comp (c->buffer->info[skippy_iter.idx]); if (first_lig_id && first_lig_comp) { /* If first component was attached to a previous ligature component, * all subsequent components should be attached to the same ligature * component, otherwise we shouldn't ligate them. */ if (first_lig_id != this_lig_id || first_lig_comp != this_lig_comp) return TRACE_RETURN (false); } else { /* If first component was NOT attached to a previous ligature component, * all subsequent components should also NOT be attached to any ligature * component, unless they are attached to the first component itself! */ if (this_lig_id && this_lig_comp && (this_lig_id != first_lig_id)) return TRACE_RETURN (false); } is_mark_ligature = is_mark_ligature && (property & HB_OT_LAYOUT_GLYPH_CLASS_MARK); total_component_count += get_lig_num_comps (c->buffer->info[skippy_iter.idx]); } /* Deal, we are forming the ligature. */ c->buffer->merge_clusters (c->buffer->idx, skippy_iter.idx + 1); unsigned int klass = is_mark_ligature ? 0 : HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE; unsigned int lig_id = is_mark_ligature ? 0 : allocate_lig_id (c->buffer); unsigned int last_lig_id = get_lig_id (c->buffer->cur()); unsigned int last_num_components = get_lig_num_comps (c->buffer->cur()); unsigned int components_so_far = last_num_components; if (!is_mark_ligature) set_lig_props_for_ligature (c->buffer->cur(), lig_id, total_component_count); c->replace_glyph (ligGlyph, klass); for (unsigned int i = 1; i < count; i++) { while (c->should_mark_skip_current_glyph ()) { if (!is_mark_ligature) { unsigned int new_lig_comp = components_so_far - last_num_components + MIN (MAX (get_lig_comp (c->buffer->cur()), 1u), last_num_components); set_lig_props_for_mark (c->buffer->cur(), lig_id, new_lig_comp); } c->buffer->next_glyph (); } last_lig_id = get_lig_id (c->buffer->cur()); last_num_components = get_lig_num_comps (c->buffer->cur()); components_so_far += last_num_components; /* Skip the base glyph */ c->buffer->idx++; } if (!is_mark_ligature && last_lig_id) { /* Re-adjust components for any marks following. */ for (unsigned int i = c->buffer->idx; i < c->buffer->len; i++) { if (last_lig_id == get_lig_id (c->buffer->info[i])) { unsigned int new_lig_comp = components_so_far - last_num_components + MIN (MAX (get_lig_comp (c->buffer->info[i]), 1u), last_num_components); set_lig_props_for_mark (c->buffer->info[i], lig_id, new_lig_comp); } else break; } } return TRACE_RETURN (true); } public: inline bool sanitize (hb_sanitize_context_t *c) { TRACE_SANITIZE (); return TRACE_RETURN (ligGlyph.sanitize (c) && component.sanitize (c)); } protected: GlyphID ligGlyph; /* GlyphID of ligature to substitute */ HeadlessArrayOf component; /* Array of component GlyphIDs--start * with the second component--ordered * in writing direction */ public: DEFINE_SIZE_ARRAY (4, component); }; struct LigatureSet { friend struct LigatureSubstFormat1; private: inline void closure (hb_closure_context_t *c) const { TRACE_CLOSURE (); unsigned int num_ligs = ligature.len; for (unsigned int i = 0; i < num_ligs; i++) (this+ligature[i]).closure (c); } inline bool would_apply (hb_would_apply_context_t *c) const { unsigned int num_ligs = ligature.len; for (unsigned int i = 0; i < num_ligs; i++) { const Ligature &lig = this+ligature[i]; if (lig.would_apply (c)) return true; } return false; } inline bool apply (hb_apply_context_t *c) const { TRACE_APPLY (); unsigned int num_ligs = ligature.len; for (unsigned int i = 0; i < num_ligs; i++) { const Ligature &lig = this+ligature[i]; if (lig.apply (c)) return TRACE_RETURN (true); } return TRACE_RETURN (false); } public: inline bool sanitize (hb_sanitize_context_t *c) { TRACE_SANITIZE (); return TRACE_RETURN (ligature.sanitize (c, this)); } protected: OffsetArrayOf ligature; /* Array LigatureSet tables * ordered by preference */ public: DEFINE_SIZE_ARRAY (2, ligature); }; struct LigatureSubstFormat1 { friend struct LigatureSubst; private: inline void closure (hb_closure_context_t *c) const { TRACE_CLOSURE (); Coverage::Iter iter; for (iter.init (this+coverage); iter.more (); iter.next ()) { if (c->glyphs->has (iter.get_glyph ())) (this+ligatureSet[iter.get_coverage ()]).closure (c); } } inline const Coverage &get_coverage (void) const { return this+coverage; } inline bool would_apply (hb_would_apply_context_t *c) const { return (this+ligatureSet[(this+coverage) (c->first)]).would_apply (c); } inline bool apply (hb_apply_context_t *c) const { TRACE_APPLY (); hb_codepoint_t glyph_id = c->buffer->cur().codepoint; unsigned int index = (this+coverage) (glyph_id); if (likely (index == NOT_COVERED)) return TRACE_RETURN (false); const LigatureSet &lig_set = this+ligatureSet[index]; return TRACE_RETURN (lig_set.apply (c)); } inline bool sanitize (hb_sanitize_context_t *c) { TRACE_SANITIZE (); return TRACE_RETURN (coverage.sanitize (c, this) && ligatureSet.sanitize (c, this)); } protected: USHORT format; /* Format identifier--format = 1 */ OffsetTo coverage; /* Offset to Coverage table--from * beginning of Substitution table */ OffsetArrayOf ligatureSet; /* Array LigatureSet tables * ordered by Coverage Index */ public: DEFINE_SIZE_ARRAY (6, ligatureSet); }; struct LigatureSubst { friend struct SubstLookupSubTable; private: inline void closure (hb_closure_context_t *c) const { TRACE_CLOSURE (); switch (u.format) { case 1: u.format1.closure (c); break; default: break; } } inline const Coverage &get_coverage (void) const { switch (u.format) { case 1: return u.format1.get_coverage (); default:return Null(Coverage); } } inline bool would_apply (hb_would_apply_context_t *c) const { switch (u.format) { case 1: return u.format1.would_apply (c); default:return false; } } inline bool apply (hb_apply_context_t *c) const { TRACE_APPLY (); switch (u.format) { case 1: return TRACE_RETURN (u.format1.apply (c)); default:return TRACE_RETURN (false); } } inline bool sanitize (hb_sanitize_context_t *c) { TRACE_SANITIZE (); if (!u.format.sanitize (c)) return TRACE_RETURN (false); switch (u.format) { case 1: return TRACE_RETURN (u.format1.sanitize (c)); default:return TRACE_RETURN (true); } } protected: union { USHORT format; /* Format identifier */ LigatureSubstFormat1 format1; } u; }; static inline bool substitute_lookup (hb_apply_context_t *c, unsigned int lookup_index); static inline void closure_lookup (hb_closure_context_t *c, unsigned int lookup_index); struct ContextSubst : Context { friend struct SubstLookupSubTable; private: inline void closure (hb_closure_context_t *c) const { TRACE_CLOSURE (); return Context::closure (c, closure_lookup); } inline bool apply (hb_apply_context_t *c) const { TRACE_APPLY (); return TRACE_RETURN (Context::apply (c, substitute_lookup)); } }; struct ChainContextSubst : ChainContext { friend struct SubstLookupSubTable; private: inline void closure (hb_closure_context_t *c) const { TRACE_CLOSURE (); return ChainContext::closure (c, closure_lookup); } inline bool apply (hb_apply_context_t *c) const { TRACE_APPLY (); return TRACE_RETURN (ChainContext::apply (c, substitute_lookup)); } }; struct ExtensionSubst : Extension { friend struct SubstLookupSubTable; friend struct SubstLookup; private: inline const struct SubstLookupSubTable& get_subtable (void) const { unsigned int offset = get_offset (); if (unlikely (!offset)) return Null(SubstLookupSubTable); return StructAtOffset (this, offset); } inline void closure (hb_closure_context_t *c) const; inline const Coverage &get_coverage (void) const; inline bool would_apply (hb_would_apply_context_t *c) const; inline bool apply (hb_apply_context_t *c) const; inline bool sanitize (hb_sanitize_context_t *c); inline bool is_reverse (void) const; }; struct ReverseChainSingleSubstFormat1 { friend struct ReverseChainSingleSubst; private: inline void closure (hb_closure_context_t *c) const { TRACE_CLOSURE (); const OffsetArrayOf &lookahead = StructAfter > (backtrack); unsigned int count; count = backtrack.len; for (unsigned int i = 0; i < count; i++) if (!(this+backtrack[i]).intersects (c->glyphs)) return; count = lookahead.len; for (unsigned int i = 0; i < count; i++) if (!(this+lookahead[i]).intersects (c->glyphs)) return; const ArrayOf &substitute = StructAfter > (lookahead); Coverage::Iter iter; for (iter.init (this+coverage); iter.more (); iter.next ()) { if (c->glyphs->has (iter.get_glyph ())) c->glyphs->add (substitute[iter.get_coverage ()]); } } inline const Coverage &get_coverage (void) const { return this+coverage; } inline bool apply (hb_apply_context_t *c) const { TRACE_APPLY (); if (unlikely (c->nesting_level_left != MAX_NESTING_LEVEL)) return TRACE_RETURN (false); /* No chaining to this type */ unsigned int index = (this+coverage) (c->buffer->cur().codepoint); if (likely (index == NOT_COVERED)) return TRACE_RETURN (false); const OffsetArrayOf &lookahead = StructAfter > (backtrack); const ArrayOf &substitute = StructAfter > (lookahead); if (match_backtrack (c, backtrack.len, (USHORT *) backtrack.array, match_coverage, this) && match_lookahead (c, lookahead.len, (USHORT *) lookahead.array, match_coverage, this, 1)) { c->replace_glyph_inplace (substitute[index]); c->buffer->idx--; /* Reverse! */ return TRACE_RETURN (true); } return TRACE_RETURN (false); } inline bool sanitize (hb_sanitize_context_t *c) { TRACE_SANITIZE (); if (!(coverage.sanitize (c, this) && backtrack.sanitize (c, this))) return TRACE_RETURN (false); OffsetArrayOf &lookahead = StructAfter > (backtrack); if (!lookahead.sanitize (c, this)) return TRACE_RETURN (false); ArrayOf &substitute = StructAfter > (lookahead); return TRACE_RETURN (substitute.sanitize (c)); } protected: USHORT format; /* Format identifier--format = 1 */ OffsetTo coverage; /* Offset to Coverage table--from * beginning of table */ OffsetArrayOf backtrack; /* Array of coverage tables * in backtracking sequence, in glyph * sequence order */ OffsetArrayOf lookaheadX; /* Array of coverage tables * in lookahead sequence, in glyph * sequence order */ ArrayOf substituteX; /* Array of substitute * GlyphIDs--ordered by Coverage Index */ public: DEFINE_SIZE_MIN (10); }; struct ReverseChainSingleSubst { friend struct SubstLookupSubTable; private: inline void closure (hb_closure_context_t *c) const { TRACE_CLOSURE (); switch (u.format) { case 1: u.format1.closure (c); break; default: break; } } inline const Coverage &get_coverage (void) const { switch (u.format) { case 1: return u.format1.get_coverage (); default:return Null(Coverage); } } inline bool apply (hb_apply_context_t *c) const { TRACE_APPLY (); switch (u.format) { case 1: return TRACE_RETURN (u.format1.apply (c)); default:return TRACE_RETURN (false); } } inline bool sanitize (hb_sanitize_context_t *c) { TRACE_SANITIZE (); if (!u.format.sanitize (c)) return TRACE_RETURN (false); switch (u.format) { case 1: return TRACE_RETURN (u.format1.sanitize (c)); default:return TRACE_RETURN (true); } } protected: union { USHORT format; /* Format identifier */ ReverseChainSingleSubstFormat1 format1; } u; }; /* * SubstLookup */ struct SubstLookupSubTable { friend struct SubstLookup; enum Type { Single = 1, Multiple = 2, Alternate = 3, Ligature = 4, Context = 5, ChainContext = 6, Extension = 7, ReverseChainSingle = 8 }; inline void closure (hb_closure_context_t *c, unsigned int lookup_type) const { TRACE_CLOSURE (); switch (lookup_type) { case Single: u.single.closure (c); break; case Multiple: u.multiple.closure (c); break; case Alternate: u.alternate.closure (c); break; case Ligature: u.ligature.closure (c); break; case Context: u.context.closure (c); break; case ChainContext: u.chainContext.closure (c); break; case Extension: u.extension.closure (c); break; case ReverseChainSingle: u.reverseChainContextSingle.closure (c); break; default: break; } } inline const Coverage &get_coverage (unsigned int lookup_type) const { switch (lookup_type) { case Single: return u.single.get_coverage (); case Multiple: return u.multiple.get_coverage (); case Alternate: return u.alternate.get_coverage (); case Ligature: return u.ligature.get_coverage (); case Context: return u.context.get_coverage (); case ChainContext: return u.chainContext.get_coverage (); case Extension: return u.extension.get_coverage (); case ReverseChainSingle: return u.reverseChainContextSingle.get_coverage (); default: return Null(Coverage); } } inline bool would_apply (hb_would_apply_context_t *c, unsigned int lookup_type) const { TRACE_WOULD_APPLY (); if (get_coverage (lookup_type).get_coverage (c->first) == NOT_COVERED) return false; if (c->len == 1) return true; /* Done! */ /* Only need to look further for lookups that support substitutions * of input longer than 1. */ switch (lookup_type) { case Ligature: return u.ligature.would_apply (c); case Context: return u.context.would_apply (c); case ChainContext: return u.chainContext.would_apply (c); case Extension: return u.extension.would_apply (c); default: return false; } } inline bool apply (hb_apply_context_t *c, unsigned int lookup_type) const { TRACE_APPLY (); switch (lookup_type) { case Single: return TRACE_RETURN (u.single.apply (c)); case Multiple: return TRACE_RETURN (u.multiple.apply (c)); case Alternate: return TRACE_RETURN (u.alternate.apply (c)); case Ligature: return TRACE_RETURN (u.ligature.apply (c)); case Context: return TRACE_RETURN (u.context.apply (c)); case ChainContext: return TRACE_RETURN (u.chainContext.apply (c)); case Extension: return TRACE_RETURN (u.extension.apply (c)); case ReverseChainSingle: return TRACE_RETURN (u.reverseChainContextSingle.apply (c)); default: return TRACE_RETURN (false); } } inline bool sanitize (hb_sanitize_context_t *c, unsigned int lookup_type) { TRACE_SANITIZE (); if (!u.header.sub_format.sanitize (c)) return TRACE_RETURN (false); switch (lookup_type) { case Single: return TRACE_RETURN (u.single.sanitize (c)); case Multiple: return TRACE_RETURN (u.multiple.sanitize (c)); case Alternate: return TRACE_RETURN (u.alternate.sanitize (c)); case Ligature: return TRACE_RETURN (u.ligature.sanitize (c)); case Context: return TRACE_RETURN (u.context.sanitize (c)); case ChainContext: return TRACE_RETURN (u.chainContext.sanitize (c)); case Extension: return TRACE_RETURN (u.extension.sanitize (c)); case ReverseChainSingle: return TRACE_RETURN (u.reverseChainContextSingle.sanitize (c)); default: return TRACE_RETURN (true); } } protected: union { struct { USHORT sub_format; } header; SingleSubst single; MultipleSubst multiple; AlternateSubst alternate; LigatureSubst ligature; ContextSubst context; ChainContextSubst chainContext; ExtensionSubst extension; ReverseChainSingleSubst reverseChainContextSingle; } u; public: DEFINE_SIZE_UNION (2, header.sub_format); }; struct SubstLookup : Lookup { inline const SubstLookupSubTable& get_subtable (unsigned int i) const { return this+CastR > (subTable)[i]; } inline static bool lookup_type_is_reverse (unsigned int lookup_type) { return lookup_type == SubstLookupSubTable::ReverseChainSingle; } inline bool is_reverse (void) const { unsigned int type = get_type (); if (unlikely (type == SubstLookupSubTable::Extension)) return CastR (get_subtable(0)).is_reverse (); return lookup_type_is_reverse (type); } inline void closure (hb_closure_context_t *c) const { unsigned int lookup_type = get_type (); unsigned int count = get_subtable_count (); for (unsigned int i = 0; i < count; i++) get_subtable (i).closure (c, lookup_type); } inline const Coverage *get_coverage (void) const { /* Only return non-NULL if there's just one Coverage table we care about. */ const Coverage *c = &get_subtable (0).get_coverage (get_type ()); unsigned int count = get_subtable_count (); for (unsigned int i = 1; i < count; i++) if (c != &get_subtable (i).get_coverage (get_type ())) return NULL; return c; } inline bool would_apply (hb_would_apply_context_t *c) const { unsigned int lookup_type = get_type (); unsigned int count = get_subtable_count (); for (unsigned int i = 0; i < count; i++) if (get_subtable (i).would_apply (c, lookup_type)) return true; return false; } inline bool apply_once (hb_apply_context_t *c) const { unsigned int lookup_type = get_type (); if (!c->check_glyph_property (&c->buffer->cur(), c->lookup_props, &c->property)) return false; unsigned int count = get_subtable_count (); for (unsigned int i = 0; i < count; i++) if (get_subtable (i).apply (c, lookup_type)) return true; return false; } inline bool apply_string (hb_apply_context_t *c) const { bool ret = false; if (unlikely (!c->buffer->len)) return false; c->set_lookup (*this); if (likely (!is_reverse ())) { /* in/out forward substitution */ c->buffer->clear_output (); c->buffer->idx = 0; /* Fast path for lookups with one coverage only (which is most). */ const Coverage *coverage = get_coverage (); if (coverage) while (c->buffer->idx < c->buffer->len) { if ((c->buffer->cur().mask & c->lookup_mask) && coverage->get_coverage (c->buffer->cur().codepoint) != NOT_COVERED && apply_once (c)) ret = true; else c->buffer->next_glyph (); } else while (c->buffer->idx < c->buffer->len) { if ((c->buffer->cur().mask & c->lookup_mask) && apply_once (c)) ret = true; else c->buffer->next_glyph (); } if (ret) c->buffer->swap_buffers (); } else { /* in-place backward substitution */ c->buffer->idx = c->buffer->len - 1; do { if ((c->buffer->cur().mask & c->lookup_mask) && apply_once (c)) ret = true; else c->buffer->idx--; } while ((int) c->buffer->idx >= 0); } return ret; } inline bool sanitize (hb_sanitize_context_t *c) { TRACE_SANITIZE (); if (unlikely (!Lookup::sanitize (c))) return TRACE_RETURN (false); OffsetArrayOf &list = CastR > (subTable); if (unlikely (!list.sanitize (c, this, get_type ()))) return TRACE_RETURN (false); if (unlikely (get_type () == SubstLookupSubTable::Extension)) { /* The spec says all subtables of an Extension lookup should * have the same type. This is specially important if one has * a reverse type! * * We just check that they are all either forward, or reverse. */ unsigned int type = get_subtable (0).u.extension.get_type (); unsigned int count = get_subtable_count (); for (unsigned int i = 1; i < count; i++) if (get_subtable (i).u.extension.get_type () != type) return TRACE_RETURN (false); } return TRACE_RETURN (true); } }; typedef OffsetListOf SubstLookupList; /* * GSUB -- The Glyph Substitution Table */ struct GSUB : GSUBGPOS { static const hb_tag_t Tag = HB_OT_TAG_GSUB; inline const SubstLookup& get_lookup (unsigned int i) const { return CastR (GSUBGPOS::get_lookup (i)); } inline bool would_substitute_lookup (hb_would_apply_context_t *c, unsigned int lookup_index) const { return get_lookup (lookup_index).would_apply (c); } inline bool substitute_lookup (hb_apply_context_t *c, unsigned int lookup_index) const { return get_lookup (lookup_index).apply_string (c); } static inline void substitute_start (hb_face_t *face, hb_buffer_t *buffer); static inline void substitute_finish (hb_face_t *face, hb_buffer_t *buffer); inline void closure_lookup (hb_closure_context_t *c, unsigned int lookup_index) const { return get_lookup (lookup_index).closure (c); } inline bool sanitize (hb_sanitize_context_t *c) { TRACE_SANITIZE (); if (unlikely (!GSUBGPOS::sanitize (c))) return TRACE_RETURN (false); OffsetTo &list = CastR > (lookupList); return TRACE_RETURN (list.sanitize (c, this)); } public: DEFINE_SIZE_STATIC (10); }; void GSUB::substitute_start (hb_face_t *face, hb_buffer_t *buffer) { HB_BUFFER_ALLOCATE_VAR (buffer, glyph_props); HB_BUFFER_ALLOCATE_VAR (buffer, lig_props); HB_BUFFER_ALLOCATE_VAR (buffer, syllable); /* TODO This pattern is duplicated from gsubgpos-private.h. Do something about it. */ const GDEF &gdef = hb_ot_layout_from_face (face) && !HB_SHAPER_DATA_IS_INVALID (hb_ot_layout_from_face (face)) ? *hb_ot_layout_from_face (face)->gdef : Null(GDEF); unsigned int count = buffer->len; for (unsigned int i = 0; i < count; i++) { buffer->info[i].lig_props() = buffer->info[i].syllable() = 0; buffer->info[i].glyph_props() = gdef.get_glyph_props (buffer->info[i].codepoint); } } void GSUB::substitute_finish (hb_face_t *face HB_UNUSED, hb_buffer_t *buffer HB_UNUSED) { } /* Out-of-class implementation for methods recursing */ inline void ExtensionSubst::closure (hb_closure_context_t *c) const { get_subtable ().closure (c, get_type ()); } inline const Coverage & ExtensionSubst::get_coverage (void) const { return get_subtable ().get_coverage (get_type ()); } inline bool ExtensionSubst::would_apply (hb_would_apply_context_t *c) const { return get_subtable ().would_apply (c, get_type ()); } inline bool ExtensionSubst::apply (hb_apply_context_t *c) const { TRACE_APPLY (); return TRACE_RETURN (get_subtable ().apply (c, get_type ())); } inline bool ExtensionSubst::sanitize (hb_sanitize_context_t *c) { TRACE_SANITIZE (); if (unlikely (!Extension::sanitize (c))) return TRACE_RETURN (false); unsigned int offset = get_offset (); if (unlikely (!offset)) return TRACE_RETURN (true); return TRACE_RETURN (StructAtOffset (this, offset).sanitize (c, get_type ())); } inline bool ExtensionSubst::is_reverse (void) const { unsigned int type = get_type (); if (unlikely (type == SubstLookupSubTable::Extension)) return CastR (get_subtable()).is_reverse (); return SubstLookup::lookup_type_is_reverse (type); } static inline void closure_lookup (hb_closure_context_t *c, unsigned int lookup_index) { const GSUB &gsub = *(hb_ot_layout_from_face (c->face)->gsub); const SubstLookup &l = gsub.get_lookup (lookup_index); if (unlikely (c->nesting_level_left == 0)) return; c->nesting_level_left--; l.closure (c); c->nesting_level_left++; } static inline bool substitute_lookup (hb_apply_context_t *c, unsigned int lookup_index) { const GSUB &gsub = *(hb_ot_layout_from_face (c->face)->gsub); const SubstLookup &l = gsub.get_lookup (lookup_index); if (unlikely (c->nesting_level_left == 0)) return false; hb_apply_context_t new_c (*c); new_c.nesting_level_left--; new_c.set_lookup (l); return l.apply_once (&new_c); } #endif /* HB_OT_LAYOUT_GSUB_TABLE_HH */