harfbuzz/src/hb-ot-layout-gsubgpos-priva...

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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
#define LOOKUP_ARGS \
layout, \
buffer, \
context_length, \
nesting_level_left, \
lookup_flag
/* Context lookups */
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 ContextLookupContext {
inline bool match (hb_codepoint_t glyph_id, const USHORT &value) const {
return match_func (glyph_id, value, match_data);
}
inline bool apply (LOOKUP_ARGS_DEF, unsigned int lookup_index) const {
return apply_func (LOOKUP_ARGS, lookup_index);
}
match_func_t match_func;
char *match_data;
apply_lookup_func_t apply_func;
};
struct LookupRecord {
inline bool apply (LOOKUP_ARGS_DEF, ContextLookupContext &context) const {
return context.apply (LOOKUP_ARGS, lookupListIndex);
}
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 context_lookup (LOOKUP_ARGS_DEF,
USHORT glyphCount, /* Including the first glyph (not matched) */
USHORT recordCount,
const USHORT value[], /* Array of match values--start with second glyph */
const LookupRecord lookupRecord[], /* Array of LookupRecords--in design order */
ContextLookupContext &context) {
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 */
/* 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.match (IN_GLYPH(j), value[i - 1])))
return false;
}
/* XXX right? or j - buffer_inpos? */
context_length = count;
/* XXX We have to jump non-matching glyphs when applying too, right? */
unsigned int record_count = recordCount;
const LookupRecord *record = lookupRecord;
for (i = 0; i < count;)
{
if ( record_count && i == record->sequenceIndex )
{
unsigned int old_pos = buffer->in_pos;
/* Apply a lookup */
bool done = record->apply (LOOKUP_ARGS, context);
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:
DEFINE_ARRAY_TYPE (USHORT, value, (glyphCount ? glyphCount - 1 : 0));
inline bool apply (LOOKUP_ARGS_DEF, ContextLookupContext &context) const {
const LookupRecord *record = (const LookupRecord *) ((const char *) value + sizeof (value[0]) * (glyphCount - 1));
return context_lookup (LOOKUP_ARGS,
glyphCount,
recordCount,
value,
record,
context);
}
private:
USHORT glyphCount; /* Total number of glyphs in input
* glyph sequence--includes the first
* glyph */
USHORT recordCount; /* Number of LookupRecords */
USHORT value[]; /* Array of match values--start with
* second glyph */
LookupRecord lookupRecord[]; /* 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 SubRule tables
* ordered by preference */
};
static inline bool glyph_match (hb_codepoint_t glyph_id, const USHORT &value, char *data) {
return glyph_id == value;
}
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 ());
const RuleSet &rule_set = this+ruleSet[index];
struct ContextLookupContext context = {
glyph_match, NULL,
apply_func
};
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);
static inline bool class_match (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;
}
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 ());
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 = {
class_match, (char *) &(this+classDef),
apply_func
};
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);
static inline bool coverage_match (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 ContextFormat3 {
friend struct Context;
private:
/* Coverage tables, in glyph sequence order */
DEFINE_OFFSET_ARRAY_TYPE (Coverage, coverage, glyphCount);
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 = {
coverage_match, (char *) this,
apply_func
};
return context_lookup (LOOKUP_ARGS,
glyphCount,
recordCount,
(const USHORT *) (coverage + 1),
record,
context);
}
inline bool apply (LOOKUP_ARGS_DEF, apply_lookup_func_t apply_func) const {
if ((*this)[0].get_coverage (IN_CURGLYPH () == 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 recordCount; /* Number of LookupRecords */
Offset coverage[]; /* Array of offsets to Coverage
* table--from beginning of
* table--in glyph
* sequence order */
LookupRecord lookupRecord[]; /* 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) {
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 */
ContextFormat1 format1;
ContextFormat2 format2;
ContextFormat3 format3;
} u;
};
DEFINE_NULL (Context, 2);
#endif /* HB_OT_LAYOUT_GSUBGPOS_PRIVATE_H */