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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;
}
static inline bool match_input (LOOKUP_ARGS_DEF,
unsigned int count, /* Including the first glyph (not matched) */
const USHORT input[], /* Array of input values--start with second glyph */
match_func_t match_func,
char *match_data,
unsigned int *context_length_out)
{
unsigned int i, j;
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unsigned int end = MIN (buffer->in_length, buffer->in_pos + context_length);
if (HB_UNLIKELY (buffer->in_pos + count > end))
return false;
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)) {
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if (HB_UNLIKELY (j + count - i == end))
return false;
j++;
}
if (HB_LIKELY (!match_func (IN_GLYPH(j), input[i - 1], match_data)))
return false;
}
*context_length_out = j - buffer->in_pos;
return true;
}
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static inline bool match_backtrack (LOOKUP_ARGS_DEF,
unsigned int count,
const USHORT backtrack[],
match_func_t match_func,
char *match_data)
{
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if (HB_UNLIKELY (buffer->out_pos < count))
return false;
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for (unsigned int i = 0, j = buffer->out_pos - 1; i < count; i++, j--) {
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while (!_hb_ot_layout_check_glyph_property (layout, OUT_ITEM (j), lookup_flag, &property)) {
if (HB_UNLIKELY (j + 1 == count - i))
return false;
j--;
}
if (HB_LIKELY (!match_func (OUT_GLYPH(j), backtrack[i], match_data)))
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return false;
}
return true;
}
static inline bool match_lookahead (LOOKUP_ARGS_DEF,
unsigned int count,
const USHORT lookahead[],
match_func_t match_func,
char *match_data,
unsigned int offset)
{
unsigned int i, j;
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unsigned int end = MIN (buffer->in_length, buffer->in_pos + context_length);
if (HB_UNLIKELY (buffer->in_pos + offset + count > end))
return false;
for (i = 0, j = buffer->in_pos + offset; i < count; i++, j++) {
while (!_hb_ot_layout_check_glyph_property (layout, OUT_ITEM (j), lookup_flag, &property)) {
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if (HB_UNLIKELY (j + count - i == end))
return false;
j++;
}
if (HB_LIKELY (!match_func (IN_GLYPH(j), lookahead[i], match_data)))
return false;
}
return true;
}
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);
static inline bool apply_lookup (LOOKUP_ARGS_DEF,
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unsigned int count, /* Including the first glyph */
unsigned int lookupCount,
const LookupRecord lookupRecord[], /* Array of LookupRecords--in design order */
apply_lookup_func_t apply_func)
{
unsigned int end = MIN (buffer->in_length, buffer->in_pos + context_length);
if (HB_UNLIKELY (buffer->in_pos + count > end))
return false;
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/* TODO We don't support lookupRecord arrays that are not increasing:
* Should be easy for in_place ones at least. */
for (unsigned int i = 0; i < count; i++) {
while (!_hb_ot_layout_check_glyph_property (layout, IN_CURITEM (), lookup_flag, &property)) {
if (HB_UNLIKELY (buffer->in_pos == end))
return true;
/* No lookup applied for this index */
_hb_buffer_next_glyph (buffer);
}
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if (lookupCount && i == lookupRecord->sequenceIndex)
{
unsigned int old_pos = buffer->in_pos;
/* Apply a lookup */
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bool done = apply_func (LOOKUP_ARGS, lookupRecord->lookupListIndex);
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lookupRecord++;
lookupCount--;
i += buffer->in_pos - old_pos;
if (HB_UNLIKELY (buffer->in_pos == end))
return true;
if (!done)
goto not_applied;
}
else
{
not_applied:
/* No lookup applied for this index */
_hb_buffer_next_glyph (buffer);
i++;
}
}
return true;
}
/* Contextual lookups */
struct ContextLookupContext {
ContextFuncs funcs;
char *match_data;
};
static inline bool context_lookup (LOOKUP_ARGS_DEF,
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unsigned int inputCount, /* Including the first glyph (not matched) */
const USHORT input[], /* Array of input values--start with second glyph */
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unsigned int lookupCount,
const LookupRecord lookupRecord[],
ContextLookupContext &context)
{
return match_input (LOOKUP_ARGS,
inputCount, input,
context.funcs.match, context.match_data,
&context_length) &&
apply_lookup (LOOKUP_ARGS,
inputCount,
lookupCount, lookupRecord,
context.funcs.apply);
}
struct Rule {
friend struct RuleSet;
private:
inline bool apply (LOOKUP_ARGS_DEF, ContextLookupContext &context) const {
const LookupRecord *lookupRecord = (const LookupRecord *)
((const char *) input +
sizeof (input[0]) * (inputCount ? inputCount - 1 : 0));
return context_lookup (LOOKUP_ARGS,
inputCount, input,
lookupCount, lookupRecord,
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 ());
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if (HB_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 ());
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if (HB_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 (LOOKUP_ARGS_DEF, apply_lookup_func_t apply_func) const {
unsigned int index = (this+coverage[0]) (IN_CURGLYPH ());
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if (HB_LIKELY (index == NOT_COVERED))
return false;
const LookupRecord *lookupRecord = (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, lookupRecord,
context);
}
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];
};
static inline bool chain_context_lookup (LOOKUP_ARGS_DEF,
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unsigned int backtrackCount,
const USHORT backtrack[],
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unsigned int inputCount, /* Including the first glyph (not matched) */
const USHORT input[], /* Array of input values--start with second glyph */
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unsigned int lookaheadCount,
const USHORT lookahead[],
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unsigned int lookupCount,
const LookupRecord lookupRecord[],
ChainContextLookupContext &context)
{
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/* First guess */
if (HB_UNLIKELY (buffer->out_pos < backtrackCount ||
buffer->in_pos + inputCount + lookaheadCount > buffer->in_length ||
inputCount + lookaheadCount > context_length))
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return false;
unsigned int offset;
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return match_backtrack (LOOKUP_ARGS,
backtrackCount, backtrack,
context.funcs.match, context.match_data[0]) &&
match_input (LOOKUP_ARGS,
inputCount, input,
context.funcs.match, context.match_data[1],
&offset) &&
match_lookahead (LOOKUP_ARGS,
lookaheadCount, lookahead,
context.funcs.match, context.match_data[2],
offset) &&
(context_length = offset, true) &&
apply_lookup (LOOKUP_ARGS,
inputCount,
lookupCount, lookupRecord,
context.funcs.apply);
}
struct ChainRule {
friend struct ChainRuleSet;
private:
inline bool apply (LOOKUP_ARGS_DEF, ChainContextLookupContext &context) const {
const HeadlessArrayOf<USHORT> &input = * (const HeadlessArrayOf<USHORT> *)
((const char *) &backtrack + backtrack.get_size ());
const ArrayOf<USHORT> &lookahead = * (const ArrayOf<USHORT> *)
((const char *) &input + input.get_size ());
const ArrayOf<LookupRecord> &lookup = * (const ArrayOf<LookupRecord> *)
((const char *) &lookahead + lookahead.get_size ());
return chain_context_lookup (LOOKUP_ARGS,
backtrack.len, backtrack.array,
input.len, input.array + 1,
lookahead.len, lookahead.array,
lookup.len, lookup.array,
context);
return false;
}
private:
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ArrayOf<USHORT>
backtrack; /* Array of backtracking values
* (to be matched before the input
* sequence) */
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HeadlessArrayOf<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>
lookupX; /* 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 ());
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if (HB_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 ());
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if (HB_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 {
}
inline bool apply (LOOKUP_ARGS_DEF, apply_lookup_func_t apply_func) const {
const OffsetArrayOf<Coverage> &input = * (const OffsetArrayOf<Coverage> *)
((const char *) &backtrack + backtrack.get_size ());
unsigned int index = (this+input[0]) (IN_CURGLYPH ());
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if (HB_LIKELY (index == NOT_COVERED))
return false;
const OffsetArrayOf<Coverage> &lookahead = * (const OffsetArrayOf<Coverage> *)
((const char *) &input + input.get_size ());
const ArrayOf<LookupRecord> &lookup = * (const ArrayOf<LookupRecord> *)
((const char *) &lookahead + lookahead.get_size ());
struct ChainContextLookupContext context = {
{match_coverage, apply_func},
{(char *) this, (char *) this, (char *) this}
};
return chain_context_lookup (LOOKUP_ARGS,
backtrack.len, (USHORT *) backtrack.array,
input.len, (USHORT *) input.array,
lookahead.len, (USHORT *) lookahead.array,
lookup.len, lookup.array,
context);
return false;
}
private:
USHORT format; /* Format identifier--format = 3 */
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OffsetArrayOf<Coverage>
backtrack; /* Array of coverage tables
* in backtracking sequence, in glyph
* sequence order */
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OffsetArrayOf<Coverage>
inputX ; /* Array of coverage
* tables in input sequence, in glyph
* sequence order */
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OffsetArrayOf<Coverage>
lookaheadX; /* Array of coverage tables
* in lookahead sequence, in glyph
* sequence order */
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ArrayOf<LookupRecord>
lookupX; /* Array of LookupRecords--in
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* 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 */