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

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/*
* 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_GSUBGPOS_PRIVATE_H
#define HB_OT_LAYOUT_GSUBGPOS_PRIVATE_H
#include "hb-ot-layout-gdef-private.h"
#include "harfbuzz-buffer-private.h" /* XXX */
#define LOOKUP_ARGS_DEF \
hb_ot_layout_t *layout, \
hb_buffer_t *buffer, \
unsigned int context_length HB_GNUC_UNUSED, \
unsigned int nesting_level_left HB_GNUC_UNUSED, \
unsigned int lookup_flag, \
unsigned int property HB_GNUC_UNUSED /* propety of first glyph */
#define LOOKUP_ARGS \
layout, \
buffer, \
context_length, \
nesting_level_left, \
lookup_flag, \
property
typedef bool (*match_func_t) (hb_codepoint_t glyph_id, const USHORT &value, char *data);
typedef bool (*apply_lookup_func_t) (LOOKUP_ARGS_DEF, unsigned int lookup_index);
struct ContextFuncs {
match_func_t match;
apply_lookup_func_t apply;
};
static inline bool match_glyph (hb_codepoint_t glyph_id, const USHORT &value, char *data) {
return glyph_id == value;
}
static inline bool match_class (hb_codepoint_t glyph_id, const USHORT &value, char *data) {
const ClassDef &class_def = * (const ClassDef *) data;
return class_def.get_class (glyph_id) == value;
}
static inline bool match_coverage (hb_codepoint_t glyph_id, const USHORT &value, char *data) {
const OffsetTo<Coverage> &coverage = * (const OffsetTo<Coverage> *) &value;
return (data+coverage) (glyph_id) != NOT_COVERED;
}
struct LookupRecord {
USHORT sequenceIndex; /* Index into current glyph
* sequence--first glyph = 0 */
USHORT lookupListIndex; /* Lookup to apply to that
* position--zero--based */
};
ASSERT_SIZE (LookupRecord, 4);
/* Contextual lookups */
struct ContextLookupContext {
ContextFuncs funcs;
char *match_data;
};
static inline bool context_lookup (LOOKUP_ARGS_DEF,
USHORT inputCount, /* Including the first glyph (not matched) */
const USHORT input[], /* Array of input values--start with second glyph */
USHORT lookupCount,
const LookupRecord lookupRecord[], /* Array of LookupRecords--in design order */
ContextLookupContext &context) {
unsigned int i, j;
unsigned int count = inputCount;
if (HB_UNLIKELY (buffer->in_pos + count > buffer->in_length ||
context_length < count))
return false; /* Not enough glyphs in input or context */
/* XXX context_length should also be checked when skipping glyphs, right?
* What does context_length really mean, anyway? */
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 (context.funcs.match (IN_GLYPH(j), input[i - 1], context.match_data)))
return false;
}
/* XXX right? or j - buffer_inpos? */
context_length = count;
/* XXX We have to jump non-matching glyphs when applying too, right? */
/* XXX We don't support lookupRecord arrays that are not increasing:
* Should be easy for in_place ones at least. */
unsigned int record_count = lookupCount;
const LookupRecord *record = lookupRecord;
for (i = 0; i < count;)
{
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if (record_count && i == record->sequenceIndex)
{
unsigned int old_pos = buffer->in_pos;
/* Apply a lookup */
bool done = context.funcs.apply (LOOKUP_ARGS, record->lookupListIndex);
record++;
record_count--;
i += buffer->in_pos - old_pos;
if (!done)
goto not_applied;
}
else
{
not_applied:
/* No lookup applied for this index */
_hb_buffer_next_glyph (buffer);
i++;
}
}
return true;
}
struct Rule {
friend struct RuleSet;
private:
inline bool apply (LOOKUP_ARGS_DEF, ContextLookupContext &context) const {
const LookupRecord *record = (const LookupRecord *) ((const char *) input + sizeof (input[0]) * (inputCount ? inputCount - 1 : 0));
return context_lookup (LOOKUP_ARGS,
inputCount,
input,
lookupCount,
record,
context);
}
private:
USHORT inputCount; /* Total number of glyphs in input
* glyph sequence--includes the first
* glyph */
USHORT lookupCount; /* Number of LookupRecords */
USHORT input[]; /* Array of match inputs--start with
* second glyph */
LookupRecord lookupRecordX[]; /* Array of LookupRecords--in
* design order */
};
ASSERT_SIZE (Rule, 4);
struct RuleSet {
inline bool apply (LOOKUP_ARGS_DEF, ContextLookupContext &context) const {
unsigned int num_rules = rule.len;
for (unsigned int i = 0; i < num_rules; i++) {
if ((this+rule[i]).apply (LOOKUP_ARGS, context))
return true;
}
return false;
}
private:
OffsetArrayOf<Rule>
rule; /* Array of Rule tables
* ordered by preference */
};
struct ContextFormat1 {
friend struct Context;
private:
inline bool apply (LOOKUP_ARGS_DEF, apply_lookup_func_t apply_func) const {
unsigned int index = (this+coverage) (IN_CURGLYPH ());
if (G_LIKELY (index == NOT_COVERED))
return false;
const RuleSet &rule_set = this+ruleSet[index];
struct ContextLookupContext context = {
{match_glyph, apply_func},
NULL
};
return rule_set.apply (LOOKUP_ARGS, context);
}
private:
USHORT format; /* Format identifier--format = 1 */
OffsetTo<Coverage>
coverage; /* Offset to Coverage table--from
* beginning of table */
OffsetArrayOf<RuleSet>
ruleSet; /* Array of RuleSet tables
* ordered by Coverage Index */
};
ASSERT_SIZE (ContextFormat1, 6);
struct ContextFormat2 {
friend struct Context;
private:
inline bool apply (LOOKUP_ARGS_DEF, apply_lookup_func_t apply_func) const {
unsigned int index = (this+coverage) (IN_CURGLYPH ());
if (G_LIKELY (index == NOT_COVERED))
return false;
const ClassDef &class_def = this+classDef;
index = class_def (IN_CURGLYPH ());
const RuleSet &rule_set = this+ruleSet[index];
/* LONGTERMTODO: Old code fetches glyph classes at most once and caches
* them across subrule lookups. Not sure it's worth it.
*/
struct ContextLookupContext context = {
{match_class, apply_func},
(char *) &class_def
};
return rule_set.apply (LOOKUP_ARGS, context);
}
private:
USHORT format; /* Format identifier--format = 2 */
OffsetTo<Coverage>
coverage; /* Offset to Coverage table--from
* beginning of table */
OffsetTo<ClassDef>
classDef; /* Offset to glyph ClassDef table--from
* beginning of table */
OffsetArrayOf<RuleSet>
ruleSet; /* Array of RuleSet tables
* ordered by class */
};
ASSERT_SIZE (ContextFormat2, 8);
struct ContextFormat3 {
friend struct Context;
private:
inline bool apply_coverage (LOOKUP_ARGS_DEF, apply_lookup_func_t apply_func) const {
const LookupRecord *record = (const LookupRecord *) ((const char *) coverage + sizeof (coverage[0]) * glyphCount);
struct ContextLookupContext context = {
{match_coverage, apply_func},
(char *) this
};
return context_lookup (LOOKUP_ARGS,
glyphCount,
(const USHORT *) (coverage + 1),
lookupCount,
record,
context);
}
inline bool apply (LOOKUP_ARGS_DEF, apply_lookup_func_t apply_func) const {
unsigned int index = (this+coverage[0]) (IN_CURGLYPH ());
if (G_LIKELY (index == NOT_COVERED))
return false;
return apply_coverage (LOOKUP_ARGS, apply_func);
}
private:
USHORT format; /* Format identifier--format = 3 */
USHORT glyphCount; /* Number of glyphs in the input glyph
* sequence */
USHORT lookupCount; /* Number of LookupRecords */
OffsetTo<Coverage>
coverage[]; /* Array of offsets to Coverage
* table in glyph sequence order */
LookupRecord lookupRecordX[]; /* Array of LookupRecords--in
* design order */
};
ASSERT_SIZE (ContextFormat3, 6);
struct Context {
protected:
bool apply (LOOKUP_ARGS_DEF, apply_lookup_func_t apply_func) const {
switch (u.format) {
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case 1: return u.format1->apply (LOOKUP_ARGS, apply_func);
case 2: return u.format2->apply (LOOKUP_ARGS, apply_func);
case 3: return u.format3->apply (LOOKUP_ARGS, apply_func);
default:return false;
}
}
private:
union {
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USHORT format; /* Format identifier */
ContextFormat1 format1[];
ContextFormat2 format2[];
ContextFormat3 format3[];
} u;
};
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ASSERT_SIZE (Context, 2);
/* Chaining Contextual lookups */
struct ChainContextLookupContext {
ContextFuncs funcs;
char *match_data[3];
};
struct ChainRule {
friend struct ChainRuleSet;
private:
inline bool apply (LOOKUP_ARGS_DEF, ChainContextLookupContext &context) const {
return false;
// const LookupRecord *record = (const LookupRecord *) ((const char *) input + sizeof (input[0]) * (inputCount ? inputCount - 1 : 0));
// return context_lookup (LOOKUP_ARGS,
// inputCount,
// input,
// lookupCount,
// record,
// context);
}
private:
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ArrayOf<USHORT>
backtrack; /* Array of backtracking values
* (to be matched before the input
* sequence) */
USHORT inputCountX; /* Total number of values in the input
* sequence (includes the first glyph) */
USHORT inputX[]; /* Array of input values (start with
* second glyph) */
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ArrayOf<USHORT>
lookaheadX; /* Array of lookahead values's (to be
* matched after the input sequence) */
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ArrayOf<LookupRecord>
lookupRecordX; /* Array of LookupRecords--in
* design order) */
};
ASSERT_SIZE (ChainRule, 8);
struct ChainRuleSet {
inline bool apply (LOOKUP_ARGS_DEF, ChainContextLookupContext &context) const {
unsigned int num_rules = rule.len;
for (unsigned int i = 0; i < num_rules; i++) {
if ((this+rule[i]).apply (LOOKUP_ARGS, context))
return true;
}
return false;
}
private:
OffsetArrayOf<ChainRule>
rule; /* Array of ChainRule tables
* ordered by preference */
};
ASSERT_SIZE (ChainRuleSet, 2);
struct ChainContextFormat1 {
friend struct ChainContext;
private:
inline bool apply (LOOKUP_ARGS_DEF, apply_lookup_func_t apply_func) const {
unsigned int index = (this+coverage) (IN_CURGLYPH ());
if (G_LIKELY (index == NOT_COVERED))
return false;
const ChainRuleSet &rule_set = this+ruleSet[index];
struct ChainContextLookupContext context = {
{match_glyph, apply_func},
{NULL, NULL, NULL}
};
return rule_set.apply (LOOKUP_ARGS, context);
}
private:
USHORT format; /* Format identifier--format = 1 */
OffsetTo<Coverage>
coverage; /* Offset to Coverage table--from
* beginning of table */
OffsetArrayOf<ChainRuleSet>
ruleSet; /* Array of ChainRuleSet tables
* ordered by Coverage Index */
};
ASSERT_SIZE (ChainContextFormat1, 6);
struct ChainContextFormat2 {
friend struct ChainContext;
private:
inline bool apply (LOOKUP_ARGS_DEF, apply_lookup_func_t apply_func) const {
unsigned int index = (this+coverage) (IN_CURGLYPH ());
if (G_LIKELY (index == NOT_COVERED))
return false;
const ClassDef &backtrack_class_def = this+backtrackClassDef;
const ClassDef &input_class_def = this+inputClassDef;
const ClassDef &lookahead_class_def = this+lookaheadClassDef;
index = input_class_def (IN_CURGLYPH ());
const ChainRuleSet &rule_set = this+ruleSet[index];
/* LONGTERMTODO: Old code fetches glyph classes at most once and caches
* them across subrule lookups. Not sure it's worth it.
*/
struct ChainContextLookupContext context = {
{match_class, apply_func},
{(char *) &backtrack_class_def,
(char *) &input_class_def,
(char *) &lookahead_class_def}
};
return rule_set.apply (LOOKUP_ARGS, context);
}
private:
USHORT format; /* Format identifier--format = 2 */
OffsetTo<Coverage>
coverage; /* Offset to Coverage table--from
* beginning of table */
OffsetTo<ClassDef>
backtrackClassDef; /* Offset to glyph ClassDef table
* containing backtrack sequence
* data--from beginning of table */
OffsetTo<ClassDef>
inputClassDef; /* Offset to glyph ClassDef
* table containing input sequence
* data--from beginning of table */
OffsetTo<ClassDef>
lookaheadClassDef; /* Offset to glyph ClassDef table
* containing lookahead sequence
* data--from beginning of table */
OffsetArrayOf<ChainRuleSet>
ruleSet; /* Array of ChainRuleSet tables
* ordered by class */
};
ASSERT_SIZE (ChainContextFormat2, 12);
struct ChainContextFormat3 {
friend struct ChainContext;
private:
inline bool apply_coverage (LOOKUP_ARGS_DEF, apply_lookup_func_t apply_func) const {
// const LookupRecord *record = (const LookupRecord *) ((const char *) coverage + sizeof (coverage[0]) * glyphCount);
struct ChainContextLookupContext context = {
{match_coverage, apply_func},
{(char *) this, (char *) this, (char *) this}
};
/*
return context_lookup (LOOKUP_ARGS,
glyphCount,
(const USHORT *) (coverage + 1),
lookupCount,
record,
context);
*/
return false;
}
inline bool apply (LOOKUP_ARGS_DEF, apply_lookup_func_t apply_func) const {
/* XXX */
unsigned int index = 0;//(this+coverage[0]) (IN_CURGLYPH ());
if (G_LIKELY (index == NOT_COVERED))
return false;
return apply_coverage (LOOKUP_ARGS, apply_func);
}
private:
USHORT format; /* Format identifier--format = 3 */
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OffsetArrayOf<Coverage>
backtrackCoverage; /* Array of coverage tables
* in backtracking sequence, in glyph
* sequence order */
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OffsetArrayOf<Coverage>
inputCoverageX ; /* Array of coverage
* tables in input sequence, in glyph
* sequence order */
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OffsetArrayOf<Coverage>
lookaheadCoverageX; /* Array of coverage tables
* in lookahead sequence, in glyph
* sequence order */
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ArrayOf<LookupRecord>
lookupRecordX; /* Array of LookupRecords--in
* design order) */
};
ASSERT_SIZE (ChainContextFormat3, 10);
struct ChainContext {
protected:
bool apply (LOOKUP_ARGS_DEF, apply_lookup_func_t apply_func) const {
switch (u.format) {
case 1: return u.format1->apply (LOOKUP_ARGS, apply_func);
case 2: return u.format2->apply (LOOKUP_ARGS, apply_func);
case 3: return u.format3->apply (LOOKUP_ARGS, apply_func);
default:return false;
}
}
private:
union {
USHORT format; /* Format identifier */
ChainContextFormat1 format1[];
ChainContextFormat2 format2[];
ChainContextFormat3 format3[];
} u;
};
ASSERT_SIZE (ChainContext, 2);
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/*
* GSUB/GPOS Common
*/
struct GSUBGPOS {
static const hb_tag_t GSUBTag = HB_TAG ('G','S','U','B');
static const hb_tag_t GPOSTag = HB_TAG ('G','P','O','S');
STATIC_DEFINE_GET_FOR_DATA (GSUBGPOS);
/* XXX check version here? */
DEFINE_TAG_LIST_INTERFACE (Script, script ); /* get_script_count (), get_script (i), get_script_tag (i) */
DEFINE_TAG_LIST_INTERFACE (Feature, feature); /* get_feature_count(), get_feature(i), get_feature_tag(i) */
DEFINE_LIST_INTERFACE (Lookup, lookup ); /* get_lookup_count (), get_lookup (i) */
// LONGTERMTODO bsearch
DEFINE_TAG_FIND_INTERFACE (Script, script ); /* find_script_index (), get_script_by_tag (tag) */
DEFINE_TAG_FIND_INTERFACE (Feature, feature); /* find_feature_index(), get_feature_by_tag(tag) */
private:
Fixed_Version version; /* Version of the GSUB/GPOS table--initially set
* to 0x00010000 */
OffsetTo<ScriptList>
scriptList; /* ScriptList table */
OffsetTo<FeatureList>
featureList; /* FeatureList table */
OffsetTo<LookupList>
lookupList; /* LookupList table */
};
ASSERT_SIZE (GSUBGPOS, 10);
#endif /* HB_OT_LAYOUT_GSUBGPOS_PRIVATE_H */