/* * Copyright (C) 2007,2008,2009 Red Hat, Inc. * * This is part of HarfBuzz, an OpenType Layout engine 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 */ #ifndef HB_OT_LAYOUT_GSUB_PRIVATE_H #define HB_OT_LAYOUT_GSUB_PRIVATE_H #include "hb-ot-layout-private.h" #include "hb-ot-layout-open-private.h" #include "hb-ot-layout-gdef-private.h" #include "harfbuzz-buffer-private.h" /* XXX */ #define DEFINE_GET_GLYPH_COVERAGE(name) \ inline unsigned int get_##name (hb_codepoint_t glyph) const { \ const Coverage &c = get_coverage (); \ return c.get_coverage (glyph); \ } #define SUBTABLE_SUBSTITUTE_ARGS_DEF \ hb_ot_layout_t *layout, \ hb_buffer_t *buffer, \ unsigned int context_length, \ unsigned int nesting_level_left HB_GNUC_UNUSED, \ unsigned int lookup_flag #define SUBTABLE_SUBSTITUTE_ARGS \ layout, \ buffer, \ context_length, \ nesting_level_left, \ lookup_flag struct SingleSubstFormat1 { friend struct SingleSubst; private: DEFINE_GET_ACCESSOR (Coverage, coverage, coverage); DEFINE_GET_GLYPH_COVERAGE (glyph_coverage); inline bool single_substitute (hb_codepoint_t &glyph_id) const { unsigned int index = get_glyph_coverage (glyph_id); if (NOT_COVERED == index) return false; glyph_id += deltaGlyphID; return true; } private: USHORT substFormat; /* Format identifier--format = 1 */ Offset coverage; /* Offset to Coverage table--from * beginning of Substitution table */ SHORT deltaGlyphID; /* Add to original GlyphID to get * substitute GlyphID */ }; ASSERT_SIZE (SingleSubstFormat1, 6); struct SingleSubstFormat2 { friend struct SingleSubst; private: DEFINE_GET_ACCESSOR (Coverage, coverage, coverage); DEFINE_GET_GLYPH_COVERAGE (glyph_coverage); inline bool single_substitute (hb_codepoint_t &glyph_id) const { unsigned int index = get_glyph_coverage (glyph_id); if (index >= glyphCount) return false; glyph_id = substitute[index]; return true; } private: USHORT substFormat; /* Format identifier--format = 2 */ Offset coverage; /* Offset to Coverage table--from * beginning of Substitution table */ USHORT glyphCount; /* Number of GlyphIDs in the Substitute * array */ GlyphID substitute[]; /* Array of substitute * GlyphIDs--ordered by Coverage Index */ }; ASSERT_SIZE (SingleSubstFormat2, 6); struct SingleSubst { friend struct SubstLookupSubTable; private: unsigned int get_size (void) const { switch (u.substFormat) { case 1: return sizeof (u.format1); case 2: return sizeof (u.format2); default:return sizeof (u.substFormat); } } inline bool single_substitute (hb_codepoint_t &glyph_id) const { switch (u.substFormat) { case 1: return u.format1.single_substitute (glyph_id); case 2: return u.format2.single_substitute (glyph_id); default:return false; } } inline bool substitute (SUBTABLE_SUBSTITUTE_ARGS_DEF) const { if (HB_UNLIKELY (context_length < 1)) return false; unsigned int property; if (!_hb_ot_layout_check_glyph_property (layout, IN_CURITEM (), lookup_flag, &property)) return false; hb_codepoint_t glyph_id = IN_CURGLYPH (); if (!single_substitute (glyph_id)) return false; _hb_buffer_replace_output_glyph (buffer, glyph_id, context_length == NO_CONTEXT); if ( _hb_ot_layout_has_new_glyph_classes (layout) ) { /* we inherit the old glyph class to the substituted glyph */ _hb_ot_layout_set_glyph_property (layout, glyph_id, property); } return true; } private: union { USHORT substFormat; /* Format identifier */ SingleSubstFormat1 format1; SingleSubstFormat2 format2; } u; }; DEFINE_NULL (SingleSubst, 2); struct Sequence { friend struct MultipleSubstFormat1; private: /* GlyphID tables, in Coverage Index order */ DEFINE_OFFSET_ARRAY_TYPE (GlyphID, substitute, glyphCount); inline void set_glyph_class (hb_ot_layout_t *layout, unsigned int property) const { unsigned int count = glyphCount; for (unsigned int n = 0; n < count; n++) _hb_ot_layout_set_glyph_property (layout, substitute[n], property); } private: USHORT glyphCount; /* Number of GlyphIDs in the Substitute * array. This should always be * greater than 0. */ GlyphID substitute[]; /* String of GlyphIDs to substitute */ }; DEFINE_NULL_ASSERT_SIZE (Sequence, 2); struct MultipleSubstFormat1 { friend struct MultipleSubst; private: /* Sequence tables, in Coverage Index order */ DEFINE_OFFSET_ARRAY_TYPE (Sequence, sequence, sequenceCount); DEFINE_GET_ACCESSOR (Coverage, coverage, coverage); DEFINE_GET_GLYPH_COVERAGE (glyph_coverage); inline bool substitute (SUBTABLE_SUBSTITUTE_ARGS_DEF) const { if (HB_UNLIKELY (context_length < 1)) return false; unsigned int property; if (!_hb_ot_layout_check_glyph_property (layout, IN_CURITEM (), lookup_flag, &property)) return false; hb_codepoint_t glyph_id = IN_CURGLYPH (); unsigned int index = get_glyph_coverage (glyph_id); const Sequence &seq = (*this)[index]; if (HB_UNLIKELY (!seq.get_len ())) return false; _hb_buffer_add_output_glyph_ids (buffer, 1, seq.glyphCount, seq.substitute, 0xFFFF, 0xFFFF); if ( _hb_ot_layout_has_new_glyph_classes (layout) ) { /* this is a guess only ... */ if ( property == HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE ) property = HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH; seq.set_glyph_class (layout, property); } return true; } private: USHORT substFormat; /* Format identifier--format = 1 */ Offset coverage; /* Offset to Coverage table--from * beginning of Substitution table */ USHORT sequenceCount; /* Number of Sequence table offsets in * the Sequence array */ Offset sequence[]; /* Array of offsets to Sequence * tables--from beginning of * Substitution table--ordered by * Coverage Index */ }; ASSERT_SIZE (MultipleSubstFormat1, 6); struct MultipleSubst { friend struct SubstLookupSubTable; private: unsigned int get_size (void) const { switch (u.substFormat) { case 1: return sizeof (u.format1); default:return sizeof (u.substFormat); } } inline bool substitute (SUBTABLE_SUBSTITUTE_ARGS_DEF) const { switch (u.substFormat) { case 1: return u.format1.substitute (SUBTABLE_SUBSTITUTE_ARGS); default:return false; } } private: union { USHORT substFormat; /* Format identifier */ MultipleSubstFormat1 format1; } u; }; DEFINE_NULL (MultipleSubst, 2); struct AlternateSet { /* GlyphIDs, in no particular order */ DEFINE_ARRAY_TYPE (GlyphID, alternate, glyphCount); private: USHORT glyphCount; /* Number of GlyphIDs in the Alternate * array */ GlyphID alternate[]; /* Array of alternate GlyphIDs--in * arbitrary order */ }; DEFINE_NULL_ASSERT_SIZE (AlternateSet, 2); struct AlternateSubstFormat1 { friend struct AlternateSubst; private: /* AlternateSet tables, in Coverage Index order */ DEFINE_OFFSET_ARRAY_TYPE (AlternateSet, alternateSet, alternateSetCount); DEFINE_GET_ACCESSOR (Coverage, coverage, coverage); DEFINE_GET_GLYPH_COVERAGE (glyph_coverage); inline bool substitute (SUBTABLE_SUBSTITUTE_ARGS_DEF) const { if (HB_UNLIKELY (context_length < 1)) return false; unsigned int property; if (!_hb_ot_layout_check_glyph_property (layout, IN_CURITEM (), lookup_flag, &property)) return false; hb_codepoint_t glyph_id = IN_CURGLYPH (); unsigned int index = get_glyph_coverage (glyph_id); const AlternateSet &alt_set = (*this)[index]; if (HB_UNLIKELY (!alt_set.get_len ())) return false; unsigned int alt_index = 0; /* XXX callback to user to choose alternate if ( gsub->altfunc ) alt_index = (gsub->altfunc)( buffer->out_pos, glyph_id, aset.GlyphCount, aset.Alternate, gsub->data ); */ if (HB_UNLIKELY (alt_index >= alt_set.get_len ())) return false; glyph_id = alt_set[alt_index]; _hb_buffer_replace_output_glyph (buffer, glyph_id, context_length == NO_CONTEXT); if ( _hb_ot_layout_has_new_glyph_classes (layout) ) { /* we inherit the old glyph class to the substituted glyph */ _hb_ot_layout_set_glyph_property (layout, glyph_id, property); } return true; } private: USHORT substFormat; /* Format identifier--format = 1 */ Offset coverage; /* Offset to Coverage table--from * beginning of Substitution table */ USHORT alternateSetCount; /* Number of AlternateSet tables */ Offset alternateSet[]; /* Array of offsets to AlternateSet * tables--from beginning of * Substitution table--ordered by * Coverage Index */ }; ASSERT_SIZE (AlternateSubstFormat1, 6); struct AlternateSubst { friend struct SubstLookupSubTable; private: unsigned int get_size (void) const { switch (u.substFormat) { case 1: return sizeof (u.format1); default:return sizeof (u.substFormat); } } inline bool substitute (SUBTABLE_SUBSTITUTE_ARGS_DEF) const { switch (u.substFormat) { case 1: return u.format1.substitute (SUBTABLE_SUBSTITUTE_ARGS); default:return false; } } private: union { USHORT substFormat; /* Format identifier */ AlternateSubstFormat1 format1; } u; }; DEFINE_NULL (AlternateSubst, 2); struct Ligature { friend struct LigatureSet; private: DEFINE_ARRAY_TYPE (GlyphID, component, (compCount ? compCount - 1 : 0)); inline bool substitute_ligature (SUBTABLE_SUBSTITUTE_ARGS_DEF, bool is_mark) const { unsigned int i, j; unsigned int property; unsigned int count = compCount; if (HB_UNLIKELY (buffer->in_pos + count > buffer->in_length || context_length < count)) return false; /* Not enough glyphs in input or context */ for (i = 1, j = buffer->in_pos + 1; i < count; i++, j++) { while (!_hb_ot_layout_check_glyph_property (layout, IN_ITEM (j), lookup_flag, &property)) { if (HB_UNLIKELY (j + count - i == buffer->in_length)) return false; j++; } if (!(property == HB_OT_LAYOUT_GLYPH_CLASS_MARK || property & LookupFlag::MarkAttachmentType)) is_mark = FALSE; if (HB_LIKELY (IN_GLYPH(j) != (*this)[i - 1])) return false; } if ( _hb_ot_layout_has_new_glyph_classes (layout) ) /* this is just a guess ... */ hb_ot_layout_set_glyph_class (layout, ligGlyph, is_mark ? HB_OT_LAYOUT_GLYPH_CLASS_MARK : HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE); if (j == buffer->in_pos + i) /* No input glyphs skipped */ /* We don't use a new ligature ID if there are no skipped glyphs and the ligature already has an ID. */ _hb_buffer_add_output_glyph_ids (buffer, i, 1, &ligGlyph, 0xFFFF, IN_LIGID (buffer->in_pos) ? 0xFFFF : _hb_buffer_allocate_ligid (buffer)); else { unsigned int lig_id = _hb_buffer_allocate_ligid (buffer); _hb_buffer_add_output_glyph (buffer, ligGlyph, 0xFFFF, lig_id); /* Now we must do a second loop to copy the skipped glyphs to `out' and assign component values to it. We start with the glyph after the first component. Glyphs between component i and i+1 belong to component i. Together with the lig_id value it is later possible to check whether a specific component value really belongs to a given ligature. */ for ( i = 0; i < count - 1; i++ ) { while (!_hb_ot_layout_check_glyph_property (layout, IN_CURITEM(), lookup_flag, &property)) _hb_buffer_add_output_glyph (buffer, IN_CURGLYPH(), i, lig_id); (buffer->in_pos)++; } /* XXX We should possibly reassign lig_id and component for any * components of a previous ligature that s now being removed as part of * this ligature. */ } return true; } private: GlyphID ligGlyph; /* GlyphID of ligature to substitute */ USHORT compCount; /* Number of components in the ligature */ GlyphID component[]; /* Array of component GlyphIDs--start * with the second component--ordered * in writing direction */ }; DEFINE_NULL_ASSERT_SIZE (Ligature, 4); struct LigatureSet { friend struct LigatureSubstFormat1; private: DEFINE_OFFSET_ARRAY_TYPE (Ligature, ligature, ligatureCount); inline bool substitute_ligature (SUBTABLE_SUBSTITUTE_ARGS_DEF, bool is_mark) const { unsigned int num_ligs = get_len (); for (unsigned int i = 0; i < num_ligs; i++) { const Ligature &lig = (*this)[i]; if (lig.substitute_ligature (SUBTABLE_SUBSTITUTE_ARGS, is_mark)) return true; } return false; } private: USHORT ligatureCount; /* Number of Ligature tables */ Offset ligature[]; /* Array of offsets to Ligature * tables--from beginning of * LigatureSet table--ordered by * preference */ }; DEFINE_NULL_ASSERT_SIZE (LigatureSet, 2); struct LigatureSubstFormat1 { friend struct LigatureSubst; private: /* LigatureSet tables, in Coverage Index order */ DEFINE_OFFSET_ARRAY_TYPE (LigatureSet, ligatureSet, ligSetCount); DEFINE_GET_ACCESSOR (Coverage, coverage, coverage); DEFINE_GET_GLYPH_COVERAGE (glyph_coverage); inline bool substitute (SUBTABLE_SUBSTITUTE_ARGS_DEF) const { unsigned int property; if (!_hb_ot_layout_check_glyph_property (layout, IN_CURITEM (), lookup_flag, &property)) return false; hb_codepoint_t glyph_id = IN_CURGLYPH (); unsigned int index = get_glyph_coverage (glyph_id); bool first_is_mark = (property == HB_OT_LAYOUT_GLYPH_CLASS_MARK || property & LookupFlag::MarkAttachmentType); const LigatureSet &lig_set = (*this)[index]; return lig_set.substitute_ligature (SUBTABLE_SUBSTITUTE_ARGS, first_is_mark); } private: USHORT substFormat; /* Format identifier--format = 1 */ Offset coverage; /* Offset to Coverage table--from * beginning of Substitution table */ USHORT ligSetCount; /* Number of LigatureSet tables */ Offset ligatureSet[]; /* Array of offsets to LigatureSet * tables--from beginning of * Substitution table--ordered by * Coverage Index */ }; ASSERT_SIZE (LigatureSubstFormat1, 6); struct LigatureSubst { friend struct SubstLookupSubTable; private: unsigned int get_size (void) const { switch (u.substFormat) { case 1: return sizeof (u.format1); default:return sizeof (u.substFormat); } } inline bool substitute (SUBTABLE_SUBSTITUTE_ARGS_DEF) const { switch (u.substFormat) { case 1: return u.format1.substitute (SUBTABLE_SUBSTITUTE_ARGS); default:return false; } } private: union { USHORT substFormat; /* Format identifier */ LigatureSubstFormat1 format1; } u; }; DEFINE_NULL (LigatureSubst, 2); struct SubstLookupRecord { /* TODO */ private: USHORT sequenceIndex; /* Index into current glyph * sequence--first glyph = 0 */ USHORT lookupListIndex; /* Lookup to apply to that * position--zero--based */ }; DEFINE_NULL_ASSERT_SIZE (SubstLookupRecord, 4); struct ContextSubstFormat1 { /* TODO */ private: USHORT substFormat; /* Format identifier--format = 1 */ Offset coverage; /* Offset to Coverage table--from * beginning of Substitution table */ USHORT subRuleSetCount; /* Number of SubRuleSet tables--must * equal GlyphCount in Coverage table */ Offset subRuleSet[]; /* Array of offsets to SubRuleSet * tables--from beginning of * Substitution table--ordered by * Coverage Index */ }; ASSERT_SIZE (ContextSubstFormat1, 6); struct SubRuleSet { /* TODO */ private: USHORT subRuleCount; /* Number of SubRule tables */ Offset subRule[]; /* Array of offsets to SubRule * tables--from beginning of SubRuleSet * table--ordered by preference */ }; DEFINE_NULL_ASSERT_SIZE (SubRuleSet, 2); struct SubRule { /* TODO */ private: USHORT glyphCount; /* Total number of glyphs in input * glyph sequence--includes the first * glyph */ USHORT substCount; /* Number of SubstLookupRecords */ GlyphID input[]; /* Array of input GlyphIDs--start with * second glyph */ SubstLookupRecord substLookupRecord[];/* Array of SubstLookupRecords--in * design order */ }; DEFINE_NULL_ASSERT_SIZE (SubRule, 4); struct ContextSubstFormat2 { /* TODO */ private: USHORT substFormat; /* Format identifier--format = 2 */ Offset coverage; /* Offset to Coverage table--from * beginning of Substitution table */ Offset classDef; /* Offset to glyph ClassDef table--from * beginning of Substitution table */ USHORT subClassSetCnt; /* Number of SubClassSet tables */ Offset subClassSet[]; /* Array of offsets to SubClassSet * tables--from beginning of * Substitution table--ordered by * class--may be NULL */ }; ASSERT_SIZE (ContextSubstFormat2, 8); struct SubClassSet { /* TODO */ private: USHORT subClassRuleCnt; /* Number of SubClassRule tables */ Offset subClassRule[]; /* Array of offsets to SubClassRule * tables--from beginning of * SubClassSet--ordered by preference */ }; DEFINE_NULL_ASSERT_SIZE (SubClassSet, 2); struct SubClassRule { /* TODO */ private: USHORT glyphCount; /* Total number of classes * specified for the context in the * rule--includes the first class */ USHORT substCount; /* Number of SubstLookupRecords */ USHORT klass[]; /* Array of classes--beginning with the * second class--to be matched to the * input glyph class sequence */ SubstLookupRecord substLookupRecord[];/* Array of SubstLookupRecords--in * design order */ }; DEFINE_NULL_ASSERT_SIZE (SubClassRule, 4); struct ContextSubstFormat3 { /* TODO */ private: USHORT substFormat; /* Format identifier--format = 3 */ USHORT glyphCount; /* Number of glyphs in the input glyph * sequence */ USHORT substCount; /* Number of SubstLookupRecords */ Offset coverage[]; /* Array of offsets to Coverage * table--from beginning of * Substitution table--in glyph * sequence order */ SubstLookupRecord substLookupRecord[];/* Array of SubstLookupRecords--in * design order */ }; ASSERT_SIZE (ContextSubstFormat3, 6); struct ChainContextSubstFormat1 { /* TODO */ private: USHORT substFormat; /* Format identifier--format = 1 */ Offset coverage; /* Offset to Coverage table--from * beginning of Substitution table */ USHORT chainSubRuleSetCount; /* Number of ChainSubRuleSet * tables--must equal GlyphCount in * Coverage table */ Offset chainSubRuleSet[]; /* Array of offsets to ChainSubRuleSet * tables--from beginning of * Substitution table--ordered by * Coverage Index */ }; ASSERT_SIZE (ChainContextSubstFormat1, 6); struct ChainSubRuleSet { /* TODO */ private: USHORT chainSubRuleCount; /* Number of ChainSubRule tables */ Offset chainSubRule[]; /* Array of offsets to ChainSubRule * tables--from beginning of * ChainSubRuleSet table--ordered * by preference */ }; DEFINE_NULL_ASSERT_SIZE (ChainSubRuleSet, 2); struct ChainSubRule { /* TODO */ private: USHORT backtrackGlyphCount; /* Total number of glyphs in the * backtrack sequence (number of * glyphs to be matched before the * first glyph) */ GlyphID backtrack[]; /* Array of backtracking GlyphID's * (to be matched before the input * sequence) */ USHORT inputGlyphCount; /* Total number of glyphs in the input * sequence (includes the first glyph) */ GlyphID input[]; /* Array of input GlyphIDs (start with * second glyph) */ USHORT lookaheadGlyphCount; /* Total number of glyphs in the look * ahead sequence (number of glyphs to * be matched after the input sequence) */ GlyphID lookAhead[]; /* Array of lookahead GlyphID's (to be * matched after the input sequence) */ USHORT substCount; /* Number of SubstLookupRecords */ SubstLookupRecord substLookupRecord[];/* Array of SubstLookupRecords--in * design order) */ }; DEFINE_NULL_ASSERT_SIZE (ChainSubRule, 8); struct ChainContextSubstFormat2 { /* TODO */ private: USHORT substFormat; /* Format identifier--format = 2 */ Offset coverage; /* Offset to Coverage table--from * beginning of Substitution table */ Offset backtrackClassDef; /* Offset to glyph ClassDef table * containing backtrack sequence * data--from beginning of Substitution * table */ Offset inputClassDef; /* Offset to glyph ClassDef * table containing input sequence * data--from beginning of Substitution * table */ Offset lookaheadClassDef; /* Offset to glyph ClassDef table * containing lookahead sequence * data--from beginning of Substitution * table */ USHORT chainSubClassSetCnt; /* Number of ChainSubClassSet tables */ Offset chainSubClassSet[]; /* Array of offsets to ChainSubClassSet * tables--from beginning of * Substitution table--ordered by input * class--may be NULL */ }; ASSERT_SIZE (ChainContextSubstFormat2, 12); struct ChainSubClassSet { /* TODO */ private: USHORT chainSubClassRuleCnt; /* Number of ChainSubClassRule tables */ Offset chainSubClassRule[]; /* Array of offsets * to ChainSubClassRule * tables--from beginning of * ChainSubClassSet--ordered by * preference */ }; DEFINE_NULL_ASSERT_SIZE (ChainSubClassSet, 2); struct ChainSubClassRule { /* TODO */ private: USHORT backtrackGlyphCount; /* Total number of glyphs in the * backtrack sequence (number of * glyphs to be matched before the * first glyph) */ USHORT backtrack[]; /* Array of backtracking classes(to be * matched before the input sequence) */ USHORT inputGlyphCount; /* Total number of classes in the input * sequence (includes the first class) */ USHORT input[]; /* Array of input classes(start with * second class; to be matched with * the input glyph sequence) */ USHORT lookaheadGlyphCount; /* Total number of classes in the * look ahead sequence (number of * classes to be matched after the * input sequence) */ USHORT lookAhead[]; /* Array of lookahead classes(to be * matched after the input sequence) */ USHORT substCount; /* Number of SubstLookupRecords */ SubstLookupRecord substLookupRecord[];/* Array of SubstLookupRecords--in * design order) */ }; DEFINE_NULL_ASSERT_SIZE (ChainSubClassRule, 8); struct ChainContextSubstFormat3 { /* TODO */ private: USHORT substFormat; /* Format identifier--format = 3 */ USHORT backtrackGlyphCount; /* Number of glyphs in the backtracking * sequence */ Offset backtrackCoverage[]; /* Array of offsets to coverage tables * in backtracking sequence, in glyph * sequence order */ USHORT inputGlyphCount; /* Number of glyphs in input sequence */ Offset inputCoverage[]; /* Array of offsets to coverage * tables in input sequence, in glyph * sequence order */ USHORT lookaheadGlyphCount; /* Number of glyphs in lookahead * sequence */ Offset lookaheadCoverage[]; /* Array of offsets to coverage tables * in lookahead sequence, in glyph * sequence order */ USHORT substCount; /* Number of SubstLookupRecords */ SubstLookupRecord substLookupRecord[];/* Array of SubstLookupRecords--in * design order */ }; ASSERT_SIZE (ChainContextSubstFormat3, 10); struct ExtensionSubstFormat1 { friend struct ExtensionSubst; private: inline unsigned int get_type (void) const { return extensionLookupType; } inline bool substitute (SUBTABLE_SUBSTITUTE_ARGS_DEF) const; private: USHORT substFormat; /* Format identifier. Set to 1. */ USHORT extensionLookupType; /* Lookup type of subtable referenced * by ExtensionOffset (i.e. the * extension subtable). */ ULONG extensionOffset; /* Offset to the extension subtable, * of lookup type subtable. */ }; ASSERT_SIZE (ExtensionSubstFormat1, 8); struct ExtensionSubst { friend struct SubstLookup; friend struct SubstLookupSubTable; private: unsigned int get_size (void) const { switch (u.substFormat) { case 1: return sizeof (u.format1); default:return sizeof (u.substFormat); } } inline unsigned int get_type (void) const { switch (u.substFormat) { case 1: return u.format1.get_type (); default:return 0; } } inline bool substitute (SUBTABLE_SUBSTITUTE_ARGS_DEF) const { switch (u.substFormat) { case 1: return u.format1.substitute (SUBTABLE_SUBSTITUTE_ARGS); default:return false; } } private: union { USHORT substFormat; /* Format identifier */ ExtensionSubstFormat1 format1; } u; }; DEFINE_NULL (ExtensionSubst, 2); struct ReverseChainSingleSubstFormat1 { /* TODO */ private: USHORT substFormat; /* Format identifier--format = 1 */ Offset coverage; /* Offset to Coverage table -- from * beginning of Substitution table */ USHORT backtrackGlyphCount; /* Number of glyphs in the backtracking * sequence */ Offset backtrackCoverage[]; /* Array of offsets to coverage tables * in backtracking sequence, in glyph * sequence order */ USHORT lookaheadGlyphCount; /* Number of glyphs in lookahead * sequence */ Offset lookaheadCoverage[]; /* Array of offsets to coverage tables * in lookahead sequence, in glyph * sequence order */ USHORT glyphCount; /* Number of GlyphIDs in the Substitute * array */ GlyphID substitute[]; /* Array of substitute * GlyphIDs--ordered by Coverage Index */ }; ASSERT_SIZE (ReverseChainSingleSubstFormat1, 10); /* * SubstLookup */ enum { GSUB_Single = 1, GSUB_Multiple = 2, GSUB_Alternate = 3, GSUB_Ligature = 4, GSUB_Context = 5, GSUB_ChainingContext = 6, GSUB_Extension = 7, GSUB_ReverseChainingContextSingle = 8, }; struct SubstLookupSubTable { DEFINE_NON_INSTANTIABLE(SubstLookupSubTable); friend struct SubstLookup; unsigned int get_size (unsigned int lookup_type) const { switch (lookup_type) { case GSUB_Single: return u.single.get_size (); case GSUB_Multiple: return u.multiple.get_size (); case GSUB_Alternate: return u.alternate.get_size (); case GSUB_Ligature: return u.ligature.get_size (); /* case GSUB_Context: case GSUB_ChainingContext: */ case GSUB_Extension: return u.extension.get_size (); /* case GSUB_ReverseChainingContextSingle: */ default:return sizeof (LookupSubTable); } } inline bool substitute (SUBTABLE_SUBSTITUTE_ARGS_DEF, unsigned int lookup_type) const { switch (lookup_type) { case GSUB_Single: return u.single.substitute (SUBTABLE_SUBSTITUTE_ARGS); case GSUB_Multiple: return u.multiple.substitute (SUBTABLE_SUBSTITUTE_ARGS); case GSUB_Alternate: return u.alternate.substitute (SUBTABLE_SUBSTITUTE_ARGS); case GSUB_Ligature: return u.ligature.substitute (SUBTABLE_SUBSTITUTE_ARGS); /* case GSUB_Context: return u.context.substitute (SUBTABLE_SUBSTITUTE_ARGS); case GSUB_ChainingContext: return u.chainingContext.substitute (SUBTABLE_SUBSTITUTE_ARGS); */ case GSUB_Extension: return u.extension.substitute (SUBTABLE_SUBSTITUTE_ARGS); /* case GSUB_ReverseChainingContextSingle: return u.reverseChainingContextSingle.substitute (SUBTABLE_SUBSTITUTE_ARGS); */ default:return false; } } private: union { USHORT substFormat; SingleSubst single; MultipleSubst multiple; AlternateSubst alternate; LigatureSubst ligature; /* ContextSubst context; ChainingContextSubst chainingContext; */ ExtensionSubst extension; /* ReverseChainingContextSingleSubst reverseChainingContextSingle; */ } u; }; /* Out-of-class implementation for methods chaining */ inline bool ExtensionSubstFormat1::substitute (SUBTABLE_SUBSTITUTE_ARGS_DEF) const { return (*(SubstLookupSubTable *)(((char *) this) + extensionOffset)).substitute (SUBTABLE_SUBSTITUTE_ARGS, get_type ()); } struct SubstLookup : Lookup { DEFINE_NON_INSTANTIABLE(SubstLookup); inline const SubstLookupSubTable& get_subtable (unsigned int i) const { return *(SubstLookupSubTable*)&(((Lookup *)this)->get_subtable (i)); } /* Like get_type(), but looks through extension lookups. * Never returns Extension */ inline unsigned int get_effective_type (void) const { unsigned int type = get_type (); if (HB_UNLIKELY (type == GSUB_Extension)) { /* Return lookup type of first extension subtable. * The spec says all of them should have the same type. * XXX check for that somehow */ type = get_subtable(0).u.extension.get_type (); } return type; } inline bool is_reverse (void) const { switch (get_effective_type ()) { case GSUB_ReverseChainingContextSingle: return true; default: return false; } } bool substitute_once (hb_ot_layout_t *layout, hb_buffer_t *buffer, unsigned int context_length, unsigned int nesting_level_left) const { unsigned int lookup_type = get_type (); unsigned int lookup_flag = get_flag (); if (HB_UNLIKELY (nesting_level_left == 0)) return false; nesting_level_left--; for (unsigned int i = 0; i < get_subtable_count (); i++) if (get_subtable (i).substitute (SUBTABLE_SUBSTITUTE_ARGS, lookup_type)) return true; return false; } bool substitute_string (hb_ot_layout_t *layout, hb_buffer_t *buffer, hb_ot_layout_feature_mask_t mask) const { bool ret = false; if (HB_LIKELY (!is_reverse ())) { /* in/out forward substitution */ _hb_buffer_clear_output (buffer); buffer->in_pos = 0; while (buffer->in_pos < buffer->in_length) { if ((~IN_PROPERTIES (buffer->in_pos) & mask) && substitute_once (layout, buffer, NO_CONTEXT, MAX_NESTING_LEVEL)) ret = true; else _hb_buffer_copy_output_glyph (buffer); } if (ret) _hb_buffer_swap (buffer); } else { /* in-place backward substitution */ buffer->in_pos = buffer->in_length - 1; do { if ((~IN_PROPERTIES (buffer->in_pos) & mask) && substitute_once (layout, buffer, NO_CONTEXT, MAX_NESTING_LEVEL)) ret = true; else buffer->in_pos--; } while ((int) buffer->in_pos >= 0); } return ret; } }; DEFINE_NULL_ALIAS (SubstLookup, Lookup); /* * GSUB */ struct GSUB : GSUBGPOS { static const hb_tag_t Tag = HB_TAG ('G','S','U','B'); STATIC_DEFINE_GET_FOR_DATA (GSUB); /* XXX check version here? */ inline const SubstLookup& get_lookup (unsigned int i) const { return *(SubstLookup*)&(((GSUBGPOS *)this)->get_lookup (i)); } }; DEFINE_NULL_ALIAS (GSUB, GSUBGPOS); #endif /* HB_OT_LAYOUT_GSUB_PRIVATE_H */