harfbuzz/src/hb-ot-layout-gsub-private.h

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/*
* Copyright (C) 2007,2008,2009 Red Hat, Inc.
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*
* 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
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#include "hb-ot-layout-private.h"
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#include "hb-ot-layout-open-private.h"
#include "hb-ot-layout-gdef-private.h"
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#include "harfbuzz-buffer-private.h" /* XXX */
#define DEFINE_GET_GLYPH_COVERAGE(name) \
inline unsigned int get_##name (hb_codepoint_t glyph) const { \
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const Coverage &c = get_coverage (); \
return c.get_coverage (glyph); \
}
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#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, \
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unsigned int lookup_flag
#define SUBTABLE_SUBSTITUTE_ARGS \
layout, \
buffer, \
context_length, \
nesting_level_left, \
lookup_flag
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struct SingleSubstFormat1 {
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friend struct SingleSubst;
private:
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DEFINE_GET_ACCESSOR (Coverage, coverage, coverage);
DEFINE_GET_GLYPH_COVERAGE (glyph_coverage);
inline bool single_substitute (hb_codepoint_t &glyph_id) const {
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unsigned int index = get_glyph_coverage (glyph_id);
if (NOT_COVERED == index)
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return false;
glyph_id += deltaGlyphID;
return true;
}
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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 {
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unsigned int index = get_glyph_coverage (glyph_id);
if (index >= glyphCount)
return false;
glyph_id = substitute[index];
return true;
}
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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;
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private:
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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;
}
}
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inline bool substitute (SUBTABLE_SUBSTITUTE_ARGS_DEF) const {
if (HB_UNLIKELY (context_length < 1))
return false;
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unsigned int property;
if (!_hb_ot_layout_check_glyph_property (layout, IN_CURITEM (), lookup_flag, &property))
return false;
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hb_codepoint_t glyph_id = IN_CURGLYPH ();
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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;
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};
DEFINE_NULL (SingleSubst, 2);
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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 {
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unsigned int count = glyphCount;
for (unsigned int n = 0; n < count; n++)
_hb_ot_layout_set_glyph_property (layout, substitute[n], property);
}
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inline bool substitute_sequence (SUBTABLE_SUBSTITUTE_ARGS_DEF, unsigned int property) const {
if (HB_UNLIKELY (!get_len ()))
return false;
_hb_buffer_add_output_glyph_ids (buffer, 1,
glyphCount, 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;
set_glyph_class (layout, property);
}
return true;
}
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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);
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inline bool substitute (SUBTABLE_SUBSTITUTE_ARGS_DEF) const {
if (HB_UNLIKELY (context_length < 1))
return false;
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unsigned int property;
if (!_hb_ot_layout_check_glyph_property (layout, IN_CURITEM (), lookup_flag, &property))
return false;
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hb_codepoint_t glyph_id = IN_CURGLYPH ();
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unsigned int index = get_glyph_coverage (glyph_id);
const Sequence &seq = (*this)[index];
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return seq.substitute_sequence (SUBTABLE_SUBSTITUTE_ARGS, property);
}
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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
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* tables--from beginning of
* Substitution table--ordered by
* Coverage Index */
};
ASSERT_SIZE (MultipleSubstFormat1, 6);
struct MultipleSubst {
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friend struct SubstLookupSubTable;
private:
inline bool substitute (SUBTABLE_SUBSTITUTE_ARGS_DEF) const {
switch (u.substFormat) {
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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);
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struct AlternateSet {
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/* GlyphIDs, in no particular order */
DEFINE_ARRAY_TYPE (GlyphID, alternate, glyphCount);
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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 {
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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;
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unsigned int property;
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if (!_hb_ot_layout_check_glyph_property (layout, IN_CURITEM (), lookup_flag, &property))
return false;
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hb_codepoint_t glyph_id = IN_CURGLYPH ();
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unsigned int index = get_glyph_coverage (glyph_id);
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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;
}
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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
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* tables--from beginning of
* Substitution table--ordered by
* Coverage Index */
};
ASSERT_SIZE (AlternateSubstFormat1, 6);
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struct AlternateSubst {
friend struct SubstLookupSubTable;
private:
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);
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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;
}
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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 {
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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);
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}
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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 */
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};
ASSERT_SIZE (LigatureSubstFormat1, 6);
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struct LigatureSubst {
friend struct SubstLookupSubTable;
private:
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);
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struct SubstLookupRecord {
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);
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struct SubRule {
friend struct SubRuleSet;
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private:
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DEFINE_ARRAY_TYPE (GlyphID, input, (glyphCount ? glyphCount - 1 : 0));
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inline bool substitute (SUBTABLE_SUBSTITUTE_ARGS_DEF) const {
unsigned int i, j;
unsigned int property;
unsigned int count = glyphCount;
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 (HB_LIKELY (IN_GLYPH(j) != (*this)[i - 1]))
return false;
}
/*
return Do_ContextSubst( gsub, sr[k].GlyphCount,
sr[k].SubstCount, sr[k].SubstLookupRecord,
buffer,
nesting_level );
*/
}
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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 */
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};
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DEFINE_NULL_ASSERT_SIZE (SubRule, 4);
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struct SubRuleSet {
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friend struct ContextSubstFormat1;
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private:
DEFINE_OFFSET_ARRAY_TYPE (SubRule, subRule, subRuleCount);
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inline bool substitute (SUBTABLE_SUBSTITUTE_ARGS_DEF) const {
unsigned int num_rules = get_len ();
for (unsigned int i = 0; i < num_rules; i++) {
const SubRule &rule = (*this)[i];
if (rule.substitute (SUBTABLE_SUBSTITUTE_ARGS))
return true;
}
return false;
}
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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);
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struct ContextSubstFormat1 {
friend struct ContextSubst;
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private:
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/* SubRuleSet tables, in Coverage Index order */
DEFINE_OFFSET_ARRAY_TYPE (SubRuleSet, subRuleSet, subRuleSetCount);
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);
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const SubRuleSet &rule_set = (*this)[index];
return rule_set.substitute (SUBTABLE_SUBSTITUTE_ARGS);
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}
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 */
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};
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ASSERT_SIZE (ContextSubstFormat1, 6);
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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 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);
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struct ContextSubstFormat2 {
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friend struct ContextSubst;
private:
inline bool substitute (SUBTABLE_SUBSTITUTE_ARGS_DEF) const {
return false;
}
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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 ContextSubstFormat3 {
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friend struct ContextSubst;
private:
inline bool substitute (SUBTABLE_SUBSTITUTE_ARGS_DEF) const {
return false;
}
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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);
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struct ContextSubst {
friend struct SubstLookupSubTable;
private:
inline bool substitute (SUBTABLE_SUBSTITUTE_ARGS_DEF) const {
switch (u.substFormat) {
case 1: return u.format1.substitute (SUBTABLE_SUBSTITUTE_ARGS);
case 2: return u.format2.substitute (SUBTABLE_SUBSTITUTE_ARGS);
case 3: return u.format3.substitute (SUBTABLE_SUBSTITUTE_ARGS);
default:return false;
}
}
private:
union {
USHORT substFormat; /* Format identifier */
ContextSubstFormat1 format1;
ContextSubstFormat2 format2;
ContextSubstFormat3 format3;
} u;
};
DEFINE_NULL (ContextSubst, 2);
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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);
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struct ChainSubRuleSet {
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/* TODO */
private:
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USHORT chainSubRuleCount; /* Number of ChainSubRule tables */
Offset chainSubRule[]; /* Array of offsets to ChainSubRule
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* tables--from beginning of
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* ChainSubRuleSet table--ordered
* by preference */
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};
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DEFINE_NULL_ASSERT_SIZE (ChainSubRuleSet, 2);
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struct ChainContextSubstFormat1 {
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/* TODO */
private:
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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
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* tables--from beginning of
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* Substitution table--ordered by
* Coverage Index */
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};
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ASSERT_SIZE (ChainContextSubstFormat1, 6);
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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);
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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 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);
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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);
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struct ExtensionSubstFormat1 {
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friend struct ExtensionSubst;
private:
inline unsigned int get_type (void) const { return extensionLookupType; }
inline bool substitute (SUBTABLE_SUBSTITUTE_ARGS_DEF) const;
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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);
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struct ExtensionSubst {
friend struct SubstLookup;
friend struct SubstLookupSubTable;
private:
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);
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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);
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/*
* SubstLookup
*/
enum {
GSUB_Single = 1,
GSUB_Multiple = 2,
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GSUB_Alternate = 3,
GSUB_Ligature = 4,
GSUB_Context = 5,
GSUB_ChainingContext = 6,
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GSUB_Extension = 7,
GSUB_ReverseChainingContextSingle = 8,
};
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struct SubstLookupSubTable {
friend struct SubstLookup;
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inline bool substitute (SUBTABLE_SUBSTITUTE_ARGS_DEF,
unsigned int lookup_type) const {
switch (lookup_type) {
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case GSUB_Single: return u.single.substitute (SUBTABLE_SUBSTITUTE_ARGS);
case GSUB_Multiple: return u.multiple.substitute (SUBTABLE_SUBSTITUTE_ARGS);
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case GSUB_Alternate: return u.alternate.substitute (SUBTABLE_SUBSTITUTE_ARGS);
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case GSUB_Ligature: return u.ligature.substitute (SUBTABLE_SUBSTITUTE_ARGS);
case GSUB_Context: return u.context.substitute (SUBTABLE_SUBSTITUTE_ARGS);
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/*
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case GSUB_ChainingContext: return u.chainingContext.substitute (SUBTABLE_SUBSTITUTE_ARGS);
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*/
case GSUB_Extension: return u.extension.substitute (SUBTABLE_SUBSTITUTE_ARGS);
/*
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case GSUB_ReverseChainingContextSingle: return u.reverseChainingContextSingle.substitute (SUBTABLE_SUBSTITUTE_ARGS);
*/
default:return false;
}
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}
private:
union {
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USHORT substFormat;
SingleSubst single;
MultipleSubst multiple;
AlternateSubst alternate;
LigatureSubst ligature;
ContextSubst context;
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/*
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ChainingContextSubst chainingContext;
*/
ExtensionSubst extension;
/*
ReverseChainingContextSingleSubst reverseChainingContextSingle;
*/
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} u;
};
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/* Out-of-class implementation for methods chaining */
inline bool ExtensionSubstFormat1::substitute (SUBTABLE_SUBSTITUTE_ARGS_DEF) const {
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/* XXX either check in sanitize or here that the lookuptype is not 7 again,
* or we can loop indefinitely. */
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return (*(SubstLookupSubTable *)(((char *) this) + extensionOffset)).substitute (SUBTABLE_SUBSTITUTE_ARGS,
get_type ());
}
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struct SubstLookup : Lookup {
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 */
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inline unsigned int get_effective_type (void) const {
unsigned int type = get_type ();
if (HB_UNLIKELY (type == GSUB_Extension)) {
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/* Return lookup type of first extension subtable.
* The spec says all of them should have the same type.
* XXX check for that somehow */
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type = get_subtable(0).u.extension.get_type ();
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}
return type;
}
inline bool is_reverse (void) const {
switch (get_effective_type ()) {
case GSUB_ReverseChainingContextSingle: return true;
default: return false;
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}
}
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bool substitute_once (hb_ot_layout_t *layout,
hb_buffer_t *buffer,
unsigned int context_length,
unsigned int nesting_level_left) const {
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unsigned int lookup_type = get_type ();
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unsigned int lookup_flag = get_flag ();
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if (HB_UNLIKELY (nesting_level_left == 0))
return false;
nesting_level_left--;
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for (unsigned int i = 0; i < get_subtable_count (); i++)
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if (get_subtable (i).substitute (SUBTABLE_SUBSTITUTE_ARGS,
lookup_type))
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return true;
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return false;
}
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bool substitute_string (hb_ot_layout_t *layout,
hb_buffer_t *buffer,
hb_ot_layout_feature_mask_t mask) const {
bool ret = false;
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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;
}
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};
DEFINE_NULL_ALIAS (SubstLookup, Lookup);
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/*
* 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? */
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inline const SubstLookup& get_lookup (unsigned int i) const {
return *(SubstLookup*)&(((GSUBGPOS *)this)->get_lookup (i));
}
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};
DEFINE_NULL_ALIAS (GSUB, GSUBGPOS);
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#endif /* HB_OT_LAYOUT_GSUB_PRIVATE_H */