harfbuzz/src/hb-ot-layout-gsub-table.hh

1272 lines
34 KiB
C++

/*
* Copyright © 2007,2008,2009,2010 Red Hat, Inc.
* Copyright © 2010,2012 Google, Inc.
*
* This is part of HarfBuzz, a text shaping 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
* Google Author(s): Behdad Esfahbod
*/
#ifndef HB_OT_LAYOUT_GSUB_TABLE_HH
#define HB_OT_LAYOUT_GSUB_TABLE_HH
#include "hb-ot-layout-gsubgpos-private.hh"
struct SingleSubstFormat1
{
friend struct SingleSubst;
private:
inline void closure (hb_closure_context_t *c) const
{
TRACE_CLOSURE ();
Coverage::Iter iter;
for (iter.init (this+coverage); iter.more (); iter.next ()) {
hb_codepoint_t glyph_id = iter.get_glyph ();
if (c->glyphs->has (glyph_id))
c->glyphs->add ((glyph_id + deltaGlyphID) & 0xFFFF);
}
}
inline bool would_apply (hb_would_apply_context_t *c) const
{
return c->len == 1 && (this+coverage) (c->first) != NOT_COVERED;
}
inline bool apply (hb_apply_context_t *c) const
{
TRACE_APPLY ();
hb_codepoint_t glyph_id = c->buffer->cur().codepoint;
unsigned int index = (this+coverage) (glyph_id);
if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);
/* According to the Adobe Annotated OpenType Suite, result is always
* limited to 16bit. */
glyph_id = (glyph_id + deltaGlyphID) & 0xFFFF;
c->replace_glyph (glyph_id);
return TRACE_RETURN (true);
}
inline bool sanitize (hb_sanitize_context_t *c) {
TRACE_SANITIZE ();
return TRACE_RETURN (coverage.sanitize (c, this) && deltaGlyphID.sanitize (c));
}
protected:
USHORT format; /* Format identifier--format = 1 */
OffsetTo<Coverage>
coverage; /* Offset to Coverage table--from
* beginning of Substitution table */
SHORT deltaGlyphID; /* Add to original GlyphID to get
* substitute GlyphID */
public:
DEFINE_SIZE_STATIC (6);
};
struct SingleSubstFormat2
{
friend struct SingleSubst;
private:
inline void closure (hb_closure_context_t *c) const
{
TRACE_CLOSURE ();
Coverage::Iter iter;
for (iter.init (this+coverage); iter.more (); iter.next ()) {
if (c->glyphs->has (iter.get_glyph ()))
c->glyphs->add (substitute[iter.get_coverage ()]);
}
}
inline bool would_apply (hb_would_apply_context_t *c) const
{
return c->len == 1 && (this+coverage) (c->first) != NOT_COVERED;
}
inline bool apply (hb_apply_context_t *c) const
{
TRACE_APPLY ();
hb_codepoint_t glyph_id = c->buffer->cur().codepoint;
unsigned int index = (this+coverage) (glyph_id);
if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);
if (unlikely (index >= substitute.len)) return TRACE_RETURN (false);
glyph_id = substitute[index];
c->replace_glyph (glyph_id);
return TRACE_RETURN (true);
}
inline bool sanitize (hb_sanitize_context_t *c) {
TRACE_SANITIZE ();
return TRACE_RETURN (coverage.sanitize (c, this) && substitute.sanitize (c));
}
protected:
USHORT format; /* Format identifier--format = 2 */
OffsetTo<Coverage>
coverage; /* Offset to Coverage table--from
* beginning of Substitution table */
ArrayOf<GlyphID>
substitute; /* Array of substitute
* GlyphIDs--ordered by Coverage Index */
public:
DEFINE_SIZE_ARRAY (6, substitute);
};
struct SingleSubst
{
friend struct SubstLookupSubTable;
private:
inline void closure (hb_closure_context_t *c) const
{
TRACE_CLOSURE ();
switch (u.format) {
case 1: u.format1.closure (c); break;
case 2: u.format2.closure (c); break;
default: break;
}
}
inline bool would_apply (hb_would_apply_context_t *c) const
{
switch (u.format) {
case 1: return u.format1.would_apply (c);
case 2: return u.format2.would_apply (c);
default:return false;
}
}
inline bool apply (hb_apply_context_t *c) const
{
TRACE_APPLY ();
switch (u.format) {
case 1: return TRACE_RETURN (u.format1.apply (c));
case 2: return TRACE_RETURN (u.format2.apply (c));
default:return TRACE_RETURN (false);
}
}
inline bool sanitize (hb_sanitize_context_t *c) {
TRACE_SANITIZE ();
if (!u.format.sanitize (c)) return TRACE_RETURN (false);
switch (u.format) {
case 1: return TRACE_RETURN (u.format1.sanitize (c));
case 2: return TRACE_RETURN (u.format2.sanitize (c));
default:return TRACE_RETURN (true);
}
}
protected:
union {
USHORT format; /* Format identifier */
SingleSubstFormat1 format1;
SingleSubstFormat2 format2;
} u;
};
struct Sequence
{
friend struct MultipleSubstFormat1;
private:
inline void closure (hb_closure_context_t *c) const
{
TRACE_CLOSURE ();
unsigned int count = substitute.len;
for (unsigned int i = 0; i < count; i++)
c->glyphs->add (substitute[i]);
}
inline bool apply (hb_apply_context_t *c) const
{
TRACE_APPLY ();
if (unlikely (!substitute.len)) return TRACE_RETURN (false);
unsigned int klass = c->property & HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE ? HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH : 0;
unsigned int count = substitute.len;
for (unsigned int i = 0; i < count; i++) {
set_lig_props (c->buffer->cur(), 0, i);
c->output_glyph (substitute.array[i], klass);
}
c->buffer->skip_glyph ();
return TRACE_RETURN (true);
}
public:
inline bool sanitize (hb_sanitize_context_t *c) {
TRACE_SANITIZE ();
return TRACE_RETURN (substitute.sanitize (c));
}
protected:
ArrayOf<GlyphID>
substitute; /* String of GlyphIDs to substitute */
public:
DEFINE_SIZE_ARRAY (2, substitute);
};
struct MultipleSubstFormat1
{
friend struct MultipleSubst;
private:
inline void closure (hb_closure_context_t *c) const
{
TRACE_CLOSURE ();
Coverage::Iter iter;
for (iter.init (this+coverage); iter.more (); iter.next ()) {
if (c->glyphs->has (iter.get_glyph ()))
(this+sequence[iter.get_coverage ()]).closure (c);
}
}
inline bool would_apply (hb_would_apply_context_t *c) const
{
return c->len == 1 && (this+coverage) (c->first) != NOT_COVERED;
}
inline bool apply (hb_apply_context_t *c) const
{
TRACE_APPLY ();
unsigned int index = (this+coverage) (c->buffer->cur().codepoint);
if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);
return TRACE_RETURN ((this+sequence[index]).apply (c));
}
inline bool sanitize (hb_sanitize_context_t *c) {
TRACE_SANITIZE ();
return TRACE_RETURN (coverage.sanitize (c, this) && sequence.sanitize (c, this));
}
protected:
USHORT format; /* Format identifier--format = 1 */
OffsetTo<Coverage>
coverage; /* Offset to Coverage table--from
* beginning of Substitution table */
OffsetArrayOf<Sequence>
sequence; /* Array of Sequence tables
* ordered by Coverage Index */
public:
DEFINE_SIZE_ARRAY (6, sequence);
};
struct MultipleSubst
{
friend struct SubstLookupSubTable;
private:
inline void closure (hb_closure_context_t *c) const
{
TRACE_CLOSURE ();
switch (u.format) {
case 1: u.format1.closure (c); break;
default: break;
}
}
inline bool would_apply (hb_would_apply_context_t *c) const
{
switch (u.format) {
case 1: return u.format1.would_apply (c);
default:return false;
}
}
inline bool apply (hb_apply_context_t *c) const
{
TRACE_APPLY ();
switch (u.format) {
case 1: return TRACE_RETURN (u.format1.apply (c));
default:return TRACE_RETURN (false);
}
}
inline bool sanitize (hb_sanitize_context_t *c) {
TRACE_SANITIZE ();
if (!u.format.sanitize (c)) return TRACE_RETURN (false);
switch (u.format) {
case 1: return TRACE_RETURN (u.format1.sanitize (c));
default:return TRACE_RETURN (true);
}
}
protected:
union {
USHORT format; /* Format identifier */
MultipleSubstFormat1 format1;
} u;
};
typedef ArrayOf<GlyphID> AlternateSet; /* Array of alternate GlyphIDs--in
* arbitrary order */
struct AlternateSubstFormat1
{
friend struct AlternateSubst;
private:
inline void closure (hb_closure_context_t *c) const
{
TRACE_CLOSURE ();
Coverage::Iter iter;
for (iter.init (this+coverage); iter.more (); iter.next ()) {
if (c->glyphs->has (iter.get_glyph ())) {
const AlternateSet &alt_set = this+alternateSet[iter.get_coverage ()];
unsigned int count = alt_set.len;
for (unsigned int i = 0; i < count; i++)
c->glyphs->add (alt_set[i]);
}
}
}
inline bool would_apply (hb_would_apply_context_t *c) const
{
return c->len == 1 && (this+coverage) (c->first) != NOT_COVERED;
}
inline bool apply (hb_apply_context_t *c) const
{
TRACE_APPLY ();
hb_codepoint_t glyph_id = c->buffer->cur().codepoint;
unsigned int index = (this+coverage) (glyph_id);
if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);
const AlternateSet &alt_set = this+alternateSet[index];
if (unlikely (!alt_set.len)) return TRACE_RETURN (false);
hb_mask_t glyph_mask = c->buffer->cur().mask;
hb_mask_t lookup_mask = c->lookup_mask;
/* Note: This breaks badly if two features enabled this lookup together. */
unsigned int shift = _hb_ctz (lookup_mask);
unsigned int alt_index = ((lookup_mask & glyph_mask) >> shift);
if (unlikely (alt_index > alt_set.len || alt_index == 0)) return TRACE_RETURN (false);
glyph_id = alt_set[alt_index - 1];
c->replace_glyph (glyph_id);
return TRACE_RETURN (true);
}
inline bool sanitize (hb_sanitize_context_t *c) {
TRACE_SANITIZE ();
return TRACE_RETURN (coverage.sanitize (c, this) && alternateSet.sanitize (c, this));
}
protected:
USHORT format; /* Format identifier--format = 1 */
OffsetTo<Coverage>
coverage; /* Offset to Coverage table--from
* beginning of Substitution table */
OffsetArrayOf<AlternateSet>
alternateSet; /* Array of AlternateSet tables
* ordered by Coverage Index */
public:
DEFINE_SIZE_ARRAY (6, alternateSet);
};
struct AlternateSubst
{
friend struct SubstLookupSubTable;
private:
inline void closure (hb_closure_context_t *c) const
{
TRACE_CLOSURE ();
switch (u.format) {
case 1: u.format1.closure (c); break;
default: break;
}
}
inline bool would_apply (hb_would_apply_context_t *c) const
{
switch (u.format) {
case 1: return u.format1.would_apply (c);
default:return false;
}
}
inline bool apply (hb_apply_context_t *c) const
{
TRACE_APPLY ();
switch (u.format) {
case 1: return TRACE_RETURN (u.format1.apply (c));
default:return TRACE_RETURN (false);
}
}
inline bool sanitize (hb_sanitize_context_t *c) {
TRACE_SANITIZE ();
if (!u.format.sanitize (c)) return TRACE_RETURN (false);
switch (u.format) {
case 1: return TRACE_RETURN (u.format1.sanitize (c));
default:return TRACE_RETURN (true);
}
}
protected:
union {
USHORT format; /* Format identifier */
AlternateSubstFormat1 format1;
} u;
};
struct Ligature
{
friend struct LigatureSet;
private:
inline void closure (hb_closure_context_t *c) const
{
TRACE_CLOSURE ();
unsigned int count = component.len;
for (unsigned int i = 1; i < count; i++)
if (!c->glyphs->has (component[i]))
return;
c->glyphs->add (ligGlyph);
}
inline bool would_apply (hb_would_apply_context_t *c) const
{
return c->len == 1 || (c->len == 2 && component.len == 2 && component[1] == c->second);
}
inline bool apply (hb_apply_context_t *c) const
{
TRACE_APPLY ();
unsigned int count = component.len;
if (unlikely (count < 1)) return TRACE_RETURN (false);
hb_apply_context_t::mark_skipping_forward_iterator_t skippy_iter (c, c->buffer->idx, count - 1);
if (skippy_iter.has_no_chance ()) return TRACE_RETURN (false);
bool first_was_mark = (c->property & HB_OT_LAYOUT_GLYPH_CLASS_MARK);
bool found_non_mark = false;
for (unsigned int i = 1; i < count; i++)
{
unsigned int property;
if (!skippy_iter.next (&property)) return TRACE_RETURN (false);
found_non_mark |= !(property & HB_OT_LAYOUT_GLYPH_CLASS_MARK);
if (likely (c->buffer->info[skippy_iter.idx].codepoint != component[i])) return TRACE_RETURN (false);
}
unsigned int klass = first_was_mark && found_non_mark ? HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE : 0;
/* Allocate new ligature id */
unsigned int lig_id = allocate_lig_id (c->buffer);
set_lig_props (c->buffer->cur(), lig_id, 0);
if (skippy_iter.idx < c->buffer->idx + count) /* No input glyphs skipped */
{
hb_codepoint_t lig_glyph = ligGlyph;
c->replace_glyphs (count, 1, &lig_glyph, klass);
}
else
{
c->buffer->merge_clusters (c->buffer->idx, skippy_iter.idx + 1);
c->replace_glyph (ligGlyph);
/* 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 (unsigned int i = 1; i < count; i++)
{
while (c->should_mark_skip_current_glyph ())
{
set_lig_props (c->buffer->cur(), lig_id, i);
c->buffer->next_glyph ();
}
/* Skip the base glyph */
c->buffer->idx++;
}
}
return TRACE_RETURN (true);
}
public:
inline bool sanitize (hb_sanitize_context_t *c) {
TRACE_SANITIZE ();
return TRACE_RETURN (ligGlyph.sanitize (c) && component.sanitize (c));
}
protected:
GlyphID ligGlyph; /* GlyphID of ligature to substitute */
HeadlessArrayOf<GlyphID>
component; /* Array of component GlyphIDs--start
* with the second component--ordered
* in writing direction */
public:
DEFINE_SIZE_ARRAY (4, component);
};
struct LigatureSet
{
friend struct LigatureSubstFormat1;
private:
inline void closure (hb_closure_context_t *c) const
{
TRACE_CLOSURE ();
unsigned int num_ligs = ligature.len;
for (unsigned int i = 0; i < num_ligs; i++)
(this+ligature[i]).closure (c);
}
inline bool would_apply (hb_would_apply_context_t *c) const
{
unsigned int num_ligs = ligature.len;
for (unsigned int i = 0; i < num_ligs; i++)
{
const Ligature &lig = this+ligature[i];
if (lig.would_apply (c))
return true;
}
return false;
}
inline bool apply (hb_apply_context_t *c) const
{
TRACE_APPLY ();
unsigned int num_ligs = ligature.len;
for (unsigned int i = 0; i < num_ligs; i++)
{
const Ligature &lig = this+ligature[i];
if (lig.apply (c)) return TRACE_RETURN (true);
}
return TRACE_RETURN (false);
}
public:
inline bool sanitize (hb_sanitize_context_t *c) {
TRACE_SANITIZE ();
return TRACE_RETURN (ligature.sanitize (c, this));
}
protected:
OffsetArrayOf<Ligature>
ligature; /* Array LigatureSet tables
* ordered by preference */
public:
DEFINE_SIZE_ARRAY (2, ligature);
};
struct LigatureSubstFormat1
{
friend struct LigatureSubst;
private:
inline void closure (hb_closure_context_t *c) const
{
TRACE_CLOSURE ();
Coverage::Iter iter;
for (iter.init (this+coverage); iter.more (); iter.next ()) {
if (c->glyphs->has (iter.get_glyph ()))
(this+ligatureSet[iter.get_coverage ()]).closure (c);
}
}
inline bool would_apply (hb_would_apply_context_t *c) const
{
unsigned int index;
return (index = (this+coverage) (c->first)) != NOT_COVERED &&
(this+ligatureSet[index]).would_apply (c);
}
inline bool apply (hb_apply_context_t *c) const
{
TRACE_APPLY ();
hb_codepoint_t glyph_id = c->buffer->cur().codepoint;
unsigned int index = (this+coverage) (glyph_id);
if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);
const LigatureSet &lig_set = this+ligatureSet[index];
return TRACE_RETURN (lig_set.apply (c));
}
inline bool sanitize (hb_sanitize_context_t *c) {
TRACE_SANITIZE ();
return TRACE_RETURN (coverage.sanitize (c, this) && ligatureSet.sanitize (c, this));
}
protected:
USHORT format; /* Format identifier--format = 1 */
OffsetTo<Coverage>
coverage; /* Offset to Coverage table--from
* beginning of Substitution table */
OffsetArrayOf<LigatureSet>
ligatureSet; /* Array LigatureSet tables
* ordered by Coverage Index */
public:
DEFINE_SIZE_ARRAY (6, ligatureSet);
};
struct LigatureSubst
{
friend struct SubstLookupSubTable;
private:
inline void closure (hb_closure_context_t *c) const
{
TRACE_CLOSURE ();
switch (u.format) {
case 1: u.format1.closure (c); break;
default: break;
}
}
inline bool would_apply (hb_would_apply_context_t *c) const
{
switch (u.format) {
case 1: return u.format1.would_apply (c);
default:return false;
}
}
inline bool apply (hb_apply_context_t *c) const
{
TRACE_APPLY ();
switch (u.format) {
case 1: return TRACE_RETURN (u.format1.apply (c));
default:return TRACE_RETURN (false);
}
}
inline bool sanitize (hb_sanitize_context_t *c) {
TRACE_SANITIZE ();
if (!u.format.sanitize (c)) return TRACE_RETURN (false);
switch (u.format) {
case 1: return TRACE_RETURN (u.format1.sanitize (c));
default:return TRACE_RETURN (true);
}
}
protected:
union {
USHORT format; /* Format identifier */
LigatureSubstFormat1 format1;
} u;
};
static inline bool substitute_lookup (hb_apply_context_t *c, unsigned int lookup_index);
static inline void closure_lookup (hb_closure_context_t *c, unsigned int lookup_index);
struct ContextSubst : Context
{
friend struct SubstLookupSubTable;
private:
inline void closure (hb_closure_context_t *c) const
{
TRACE_CLOSURE ();
return Context::closure (c, closure_lookup);
}
inline bool apply (hb_apply_context_t *c) const
{
TRACE_APPLY ();
return TRACE_RETURN (Context::apply (c, substitute_lookup));
}
};
struct ChainContextSubst : ChainContext
{
friend struct SubstLookupSubTable;
private:
inline void closure (hb_closure_context_t *c) const
{
TRACE_CLOSURE ();
return ChainContext::closure (c, closure_lookup);
}
inline bool apply (hb_apply_context_t *c) const
{
TRACE_APPLY ();
return TRACE_RETURN (ChainContext::apply (c, substitute_lookup));
}
};
struct ExtensionSubst : Extension
{
friend struct SubstLookupSubTable;
friend struct SubstLookup;
private:
inline const struct SubstLookupSubTable& get_subtable (void) const
{
unsigned int offset = get_offset ();
if (unlikely (!offset)) return Null(SubstLookupSubTable);
return StructAtOffset<SubstLookupSubTable> (this, offset);
}
inline void closure (hb_closure_context_t *c) const;
inline bool would_apply (hb_would_apply_context_t *c) const;
inline bool apply (hb_apply_context_t *c) const;
inline bool sanitize (hb_sanitize_context_t *c);
inline bool is_reverse (void) const;
};
struct ReverseChainSingleSubstFormat1
{
friend struct ReverseChainSingleSubst;
private:
inline void closure (hb_closure_context_t *c) const
{
TRACE_CLOSURE ();
const OffsetArrayOf<Coverage> &lookahead = StructAfter<OffsetArrayOf<Coverage> > (backtrack);
unsigned int count;
count = backtrack.len;
for (unsigned int i = 0; i < count; i++)
if (!(this+backtrack[i]).intersects (c->glyphs))
return;
count = lookahead.len;
for (unsigned int i = 0; i < count; i++)
if (!(this+lookahead[i]).intersects (c->glyphs))
return;
const ArrayOf<GlyphID> &substitute = StructAfter<ArrayOf<GlyphID> > (lookahead);
Coverage::Iter iter;
for (iter.init (this+coverage); iter.more (); iter.next ()) {
if (c->glyphs->has (iter.get_glyph ()))
c->glyphs->add (substitute[iter.get_coverage ()]);
}
}
inline bool apply (hb_apply_context_t *c) const
{
TRACE_APPLY ();
if (unlikely (c->nesting_level_left != MAX_NESTING_LEVEL))
return TRACE_RETURN (false); /* No chaining to this type */
unsigned int index = (this+coverage) (c->buffer->cur().codepoint);
if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);
const OffsetArrayOf<Coverage> &lookahead = StructAfter<OffsetArrayOf<Coverage> > (backtrack);
const ArrayOf<GlyphID> &substitute = StructAfter<ArrayOf<GlyphID> > (lookahead);
if (match_backtrack (c,
backtrack.len, (USHORT *) backtrack.array,
match_coverage, this) &&
match_lookahead (c,
lookahead.len, (USHORT *) lookahead.array,
match_coverage, this,
1))
{
c->buffer->cur().codepoint = substitute[index];
c->buffer->idx--; /* Reverse! */
return TRACE_RETURN (true);
}
return TRACE_RETURN (false);
}
inline bool sanitize (hb_sanitize_context_t *c) {
TRACE_SANITIZE ();
if (!(coverage.sanitize (c, this) && backtrack.sanitize (c, this)))
return TRACE_RETURN (false);
OffsetArrayOf<Coverage> &lookahead = StructAfter<OffsetArrayOf<Coverage> > (backtrack);
if (!lookahead.sanitize (c, this))
return TRACE_RETURN (false);
ArrayOf<GlyphID> &substitute = StructAfter<ArrayOf<GlyphID> > (lookahead);
return TRACE_RETURN (substitute.sanitize (c));
}
protected:
USHORT format; /* Format identifier--format = 1 */
OffsetTo<Coverage>
coverage; /* Offset to Coverage table--from
* beginning of table */
OffsetArrayOf<Coverage>
backtrack; /* Array of coverage tables
* in backtracking sequence, in glyph
* sequence order */
OffsetArrayOf<Coverage>
lookaheadX; /* Array of coverage tables
* in lookahead sequence, in glyph
* sequence order */
ArrayOf<GlyphID>
substituteX; /* Array of substitute
* GlyphIDs--ordered by Coverage Index */
public:
DEFINE_SIZE_MIN (10);
};
struct ReverseChainSingleSubst
{
friend struct SubstLookupSubTable;
private:
inline void closure (hb_closure_context_t *c) const
{
TRACE_CLOSURE ();
switch (u.format) {
case 1: u.format1.closure (c); break;
default: break;
}
}
inline bool apply (hb_apply_context_t *c) const
{
TRACE_APPLY ();
switch (u.format) {
case 1: return TRACE_RETURN (u.format1.apply (c));
default:return TRACE_RETURN (false);
}
}
inline bool sanitize (hb_sanitize_context_t *c) {
TRACE_SANITIZE ();
if (!u.format.sanitize (c)) return TRACE_RETURN (false);
switch (u.format) {
case 1: return TRACE_RETURN (u.format1.sanitize (c));
default:return TRACE_RETURN (true);
}
}
protected:
union {
USHORT format; /* Format identifier */
ReverseChainSingleSubstFormat1 format1;
} u;
};
/*
* SubstLookup
*/
struct SubstLookupSubTable
{
friend struct SubstLookup;
enum Type {
Single = 1,
Multiple = 2,
Alternate = 3,
Ligature = 4,
Context = 5,
ChainContext = 6,
Extension = 7,
ReverseChainSingle = 8
};
inline void closure (hb_closure_context_t *c,
unsigned int lookup_type) const
{
TRACE_CLOSURE ();
switch (lookup_type) {
case Single: u.single.closure (c); break;
case Multiple: u.multiple.closure (c); break;
case Alternate: u.alternate.closure (c); break;
case Ligature: u.ligature.closure (c); break;
case Context: u.context.closure (c); break;
case ChainContext: u.chainContext.closure (c); break;
case Extension: u.extension.closure (c); break;
case ReverseChainSingle: u.reverseChainContextSingle.closure (c); break;
default: break;
}
}
inline bool can_use_fast_path (unsigned int lookup_type) const
{
/* Fast path, for those that have coverage in the same place.
* Note that ReverseChainSingle can also go through this but
* it's not worth the effort. */
return likely (lookup_type && lookup_type < Context) ||
(hb_in_range<unsigned int> (lookup_type, Context, ChainContext) &&
hb_in_range<unsigned int> (u.header.sub_format, 1, 2));
}
inline bool would_apply (hb_would_apply_context_t *c,
unsigned int lookup_type) const
{
TRACE_WOULD_APPLY ();
if (can_use_fast_path (lookup_type))
{
unsigned int index = (this+u.header.coverage) (c->first);
if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);
}
switch (lookup_type) {
case Single: return u.single.would_apply (c);
case Multiple: return u.multiple.would_apply (c);
case Alternate: return u.alternate.would_apply (c);
case Ligature: return u.ligature.would_apply (c);
case Context: return u.context.would_apply (c);
case ChainContext: return u.chainContext.would_apply (c);
case Extension: return u.extension.would_apply (c);
default: return false;
}
}
inline bool apply (hb_apply_context_t *c, unsigned int lookup_type) const
{
TRACE_APPLY ();
if (can_use_fast_path (lookup_type))
{
hb_codepoint_t glyph_id = c->buffer->cur().codepoint;
unsigned int index = (this+u.header.coverage) (glyph_id);
if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);
}
switch (lookup_type) {
case Single: return TRACE_RETURN (u.single.apply (c));
case Multiple: return TRACE_RETURN (u.multiple.apply (c));
case Alternate: return TRACE_RETURN (u.alternate.apply (c));
case Ligature: return TRACE_RETURN (u.ligature.apply (c));
case Context: return TRACE_RETURN (u.context.apply (c));
case ChainContext: return TRACE_RETURN (u.chainContext.apply (c));
case Extension: return TRACE_RETURN (u.extension.apply (c));
case ReverseChainSingle: return TRACE_RETURN (u.reverseChainContextSingle.apply (c));
default: return TRACE_RETURN (false);
}
}
inline bool sanitize (hb_sanitize_context_t *c, unsigned int lookup_type) {
TRACE_SANITIZE ();
if (!u.header.sub_format.sanitize (c) ||
(can_use_fast_path (lookup_type) && !u.header.coverage.sanitize (c, this)))
return TRACE_RETURN (false);
switch (lookup_type) {
case Single: return TRACE_RETURN (u.single.sanitize (c));
case Multiple: return TRACE_RETURN (u.multiple.sanitize (c));
case Alternate: return TRACE_RETURN (u.alternate.sanitize (c));
case Ligature: return TRACE_RETURN (u.ligature.sanitize (c));
case Context: return TRACE_RETURN (u.context.sanitize (c));
case ChainContext: return TRACE_RETURN (u.chainContext.sanitize (c));
case Extension: return TRACE_RETURN (u.extension.sanitize (c));
case ReverseChainSingle: return TRACE_RETURN (u.reverseChainContextSingle.sanitize (c));
default: return TRACE_RETURN (true);
}
}
protected:
union {
struct {
USHORT sub_format;
OffsetTo<Coverage> coverage;
} header;
SingleSubst single;
MultipleSubst multiple;
AlternateSubst alternate;
LigatureSubst ligature;
ContextSubst context;
ChainContextSubst chainContext;
ExtensionSubst extension;
ReverseChainSingleSubst reverseChainContextSingle;
} u;
public:
DEFINE_SIZE_UNION (2, header.sub_format);
};
struct SubstLookup : Lookup
{
inline const SubstLookupSubTable& get_subtable (unsigned int i) const
{ return this+CastR<OffsetArrayOf<SubstLookupSubTable> > (subTable)[i]; }
inline static bool lookup_type_is_reverse (unsigned int lookup_type)
{ return lookup_type == SubstLookupSubTable::ReverseChainSingle; }
inline bool is_reverse (void) const
{
unsigned int type = get_type ();
if (unlikely (type == SubstLookupSubTable::Extension))
return CastR<ExtensionSubst> (get_subtable(0)).is_reverse ();
return lookup_type_is_reverse (type);
}
inline void closure (hb_closure_context_t *c) const
{
unsigned int lookup_type = get_type ();
unsigned int count = get_subtable_count ();
for (unsigned int i = 0; i < count; i++)
get_subtable (i).closure (c, lookup_type);
}
inline bool would_apply (hb_would_apply_context_t *c) const
{
unsigned int lookup_type = get_type ();
unsigned int count = get_subtable_count ();
for (unsigned int i = 0; i < count; i++)
if (get_subtable (i).would_apply (c, lookup_type))
return true;
return false;
}
inline bool apply_once (hb_apply_context_t *c) const
{
unsigned int lookup_type = get_type ();
if (!_hb_ot_layout_check_glyph_property (c->face, &c->buffer->cur(), c->lookup_props, &c->property))
return false;
/* TODO: For the most common case this can move out of the main
* loop, but it's not a big deal for now. */
if (unlikely (lookup_type == SubstLookupSubTable::Extension))
{
/* The spec says all subtables should have the same type.
* This is specially important if one has a reverse type!
*
* This is rather slow to do this here for every glyph,
* but it's easiest, and who uses extension lookups anyway?!*/
unsigned int type = get_subtable(0).u.extension.get_type ();
unsigned int count = get_subtable_count ();
for (unsigned int i = 1; i < count; i++)
if (get_subtable(i).u.extension.get_type () != type)
return false;
}
unsigned int count = get_subtable_count ();
for (unsigned int i = 0; i < count; i++)
if (get_subtable (i).apply (c, lookup_type))
return true;
return false;
}
inline bool apply_string (hb_apply_context_t *c) const
{
bool ret = false;
if (unlikely (!c->buffer->len))
return false;
c->set_lookup (*this);
if (likely (!is_reverse ()))
{
/* in/out forward substitution */
c->buffer->clear_output ();
c->buffer->idx = 0;
while (c->buffer->idx < c->buffer->len)
{
if ((c->buffer->cur().mask & c->lookup_mask) && apply_once (c))
ret = true;
else
c->buffer->next_glyph ();
}
if (ret)
c->buffer->swap_buffers ();
}
else
{
/* in-place backward substitution */
c->buffer->idx = c->buffer->len - 1;
do
{
if ((c->buffer->cur().mask & c->lookup_mask) && apply_once (c))
ret = true;
else
c->buffer->idx--;
}
while ((int) c->buffer->idx >= 0);
}
return ret;
}
inline bool sanitize (hb_sanitize_context_t *c) {
TRACE_SANITIZE ();
if (unlikely (!Lookup::sanitize (c))) return TRACE_RETURN (false);
OffsetArrayOf<SubstLookupSubTable> &list = CastR<OffsetArrayOf<SubstLookupSubTable> > (subTable);
return TRACE_RETURN (list.sanitize (c, this, get_type ()));
}
};
typedef OffsetListOf<SubstLookup> SubstLookupList;
/*
* GSUB -- The Glyph Substitution Table
*/
struct GSUB : GSUBGPOS
{
static const hb_tag_t Tag = HB_OT_TAG_GSUB;
inline const SubstLookup& get_lookup (unsigned int i) const
{ return CastR<SubstLookup> (GSUBGPOS::get_lookup (i)); }
inline bool would_substitute_lookup (hb_would_apply_context_t *c, unsigned int lookup_index) const
{ return get_lookup (lookup_index).would_apply (c); }
inline bool substitute_lookup (hb_apply_context_t *c, unsigned int lookup_index) const
{ return get_lookup (lookup_index).apply_string (c); }
static inline void substitute_start (hb_buffer_t *buffer);
static inline void substitute_finish (hb_buffer_t *buffer);
inline void closure_lookup (hb_closure_context_t *c,
unsigned int lookup_index) const
{ return get_lookup (lookup_index).closure (c); }
inline bool sanitize (hb_sanitize_context_t *c) {
TRACE_SANITIZE ();
if (unlikely (!GSUBGPOS::sanitize (c))) return TRACE_RETURN (false);
OffsetTo<SubstLookupList> &list = CastR<OffsetTo<SubstLookupList> > (lookupList);
return TRACE_RETURN (list.sanitize (c, this));
}
public:
DEFINE_SIZE_STATIC (10);
};
void
GSUB::substitute_start (hb_buffer_t *buffer)
{
HB_BUFFER_ALLOCATE_VAR (buffer, props_cache);
HB_BUFFER_ALLOCATE_VAR (buffer, lig_props);
HB_BUFFER_ALLOCATE_VAR (buffer, syllable);
unsigned int count = buffer->len;
for (unsigned int i = 0; i < count; i++)
buffer->info[i].props_cache() = buffer->info[i].lig_props() = buffer->info[i].syllable() = 0;
}
void
GSUB::substitute_finish (hb_buffer_t *buffer HB_UNUSED)
{
}
/* Out-of-class implementation for methods recursing */
inline void ExtensionSubst::closure (hb_closure_context_t *c) const
{
get_subtable ().closure (c, get_type ());
}
inline bool ExtensionSubst::would_apply (hb_would_apply_context_t *c) const
{
return get_subtable ().would_apply (c, get_type ());
}
inline bool ExtensionSubst::apply (hb_apply_context_t *c) const
{
TRACE_APPLY ();
return TRACE_RETURN (get_subtable ().apply (c, get_type ()));
}
inline bool ExtensionSubst::sanitize (hb_sanitize_context_t *c)
{
TRACE_SANITIZE ();
if (unlikely (!Extension::sanitize (c))) return TRACE_RETURN (false);
unsigned int offset = get_offset ();
if (unlikely (!offset)) return TRACE_RETURN (true);
return TRACE_RETURN (StructAtOffset<SubstLookupSubTable> (this, offset).sanitize (c, get_type ()));
}
inline bool ExtensionSubst::is_reverse (void) const
{
unsigned int type = get_type ();
if (unlikely (type == SubstLookupSubTable::Extension))
return CastR<ExtensionSubst> (get_subtable()).is_reverse ();
return SubstLookup::lookup_type_is_reverse (type);
}
static inline void closure_lookup (hb_closure_context_t *c, unsigned int lookup_index)
{
const GSUB &gsub = *(hb_ot_layout_from_face (c->face)->gsub);
const SubstLookup &l = gsub.get_lookup (lookup_index);
if (unlikely (c->nesting_level_left == 0))
return;
c->nesting_level_left--;
l.closure (c);
c->nesting_level_left++;
}
static inline bool substitute_lookup (hb_apply_context_t *c, unsigned int lookup_index)
{
const GSUB &gsub = *(hb_ot_layout_from_face (c->face)->gsub);
const SubstLookup &l = gsub.get_lookup (lookup_index);
if (unlikely (c->nesting_level_left == 0))
return false;
hb_apply_context_t new_c (*c);
new_c.nesting_level_left--;
new_c.set_lookup (l);
return l.apply_once (&new_c);
}
#endif /* HB_OT_LAYOUT_GSUB_TABLE_HH */