harfbuzz/src/hb-aat-layout-morx-table.hh

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/*
* Copyright © 2017 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.
*
* Google Author(s): Behdad Esfahbod
*/
#ifndef HB_AAT_LAYOUT_MORX_TABLE_HH
#define HB_AAT_LAYOUT_MORX_TABLE_HH
#include "hb-open-type.hh"
#include "hb-aat-layout-common.hh"
#include "hb-ot-layout-common.hh"
/*
* morx -- Extended Glyph Metamorphosis
* https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6morx.html
*/
#define HB_AAT_TAG_morx HB_TAG('m','o','r','x')
namespace AAT {
using namespace OT;
struct RearrangementSubtable
{
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typedef void EntryData;
struct driver_context_t
{
static const bool in_place = true;
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enum Flags
{
MarkFirst = 0x8000, /* If set, make the current glyph the first
* glyph to be rearranged. */
DontAdvance = 0x4000, /* If set, don't advance to the next glyph
* before going to the new state. This means
* that the glyph index doesn't change, even
* if the glyph at that index has changed. */
MarkLast = 0x2000, /* If set, make the current glyph the last
* glyph to be rearranged. */
Reserved = 0x1FF0, /* These bits are reserved and should be set to 0. */
Verb = 0x000F, /* The type of rearrangement specified. */
};
inline driver_context_t (const RearrangementSubtable *table) :
ret (false),
start (0), end (0) {}
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inline bool is_actionable (StateTableDriver<EntryData> *driver,
const Entry<EntryData> *entry)
{
return (entry->flags & Verb) && start < end;
}
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inline bool transition (StateTableDriver<EntryData> *driver,
const Entry<EntryData> *entry)
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{
hb_buffer_t *buffer = driver->buffer;
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unsigned int flags = entry->flags;
if (flags & MarkFirst)
start = buffer->idx;
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if (flags & MarkLast)
end = MIN (buffer->idx + 1, buffer->len);
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if ((flags & Verb) && start < end)
{
/* The following map has two nibbles, for start-side
* and end-side. Values of 0,1,2 mean move that many
* to the other side. Value of 3 means move 2 and
* flip them. */
const unsigned char map[16] =
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{
0x00, /* 0 no change */
0x10, /* 1 Ax => xA */
0x01, /* 2 xD => Dx */
0x11, /* 3 AxD => DxA */
0x20, /* 4 ABx => xAB */
0x30, /* 5 ABx => xBA */
0x02, /* 6 xCD => CDx */
0x03, /* 7 xCD => DCx */
0x12, /* 8 AxCD => CDxA */
0x13, /* 9 AxCD => DCxA */
0x21, /* 10 ABxD => DxAB */
0x31, /* 11 ABxD => DxBA */
0x22, /* 12 ABxCD => CDxAB */
0x32, /* 13 ABxCD => CDxBA */
0x23, /* 14 ABxCD => DCxAB */
0x33, /* 15 ABxCD => DCxBA */
};
unsigned int m = map[flags & Verb];
unsigned int l = MIN<unsigned int> (2, m >> 4);
unsigned int r = MIN<unsigned int> (2, m & 0x0F);
bool reverse_l = 3 == (m >> 4);
bool reverse_r = 3 == (m & 0x0F);
if (end - start >= l + r)
{
buffer->merge_clusters (start, MIN (buffer->idx + 1, buffer->len));
buffer->merge_clusters (start, end);
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hb_glyph_info_t *info = buffer->info;
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hb_glyph_info_t buf[4];
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memcpy (buf, info + start, l * sizeof (buf[0]));
memcpy (buf + 2, info + end - r, r * sizeof (buf[0]));
if (l != r)
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memmove (info + start + r, info + start + l, (end - start - l - r) * sizeof (buf[0]));
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memcpy (info + start, buf + 2, r * sizeof (buf[0]));
memcpy (info + end - l, buf, l * sizeof (buf[0]));
if (reverse_l)
{
buf[0] = info[end - 1];
info[end - 1] = info[end - 2];
info[end - 2] = buf[0];
}
if (reverse_r)
{
buf[0] = info[start];
info[start] = info[start + 1];
info[start + 1] = buf[0];
}
}
}
return true;
}
public:
bool ret;
private:
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unsigned int start;
unsigned int end;
};
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inline bool apply (hb_aat_apply_context_t *c) const
{
TRACE_APPLY (this);
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driver_context_t dc (this);
StateTableDriver<void> driver (machine, c->buffer, c->face);
driver.drive (&dc);
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return_trace (dc.ret);
}
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (machine.sanitize (c));
}
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protected:
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StateTable<EntryData> machine;
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public:
DEFINE_SIZE_STATIC (16);
};
struct ContextualSubtable
{
struct EntryData
{
HBUINT16 markIndex; /* Index of the substitution table for the
* marked glyph (use 0xFFFF for none). */
HBUINT16 currentIndex; /* Index of the substitution table for the
* current glyph (use 0xFFFF for none). */
public:
DEFINE_SIZE_STATIC (4);
};
struct driver_context_t
{
static const bool in_place = true;
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enum Flags
{
SetMark = 0x8000, /* If set, make the current glyph the marked glyph. */
DontAdvance = 0x4000, /* If set, don't advance to the next glyph before
* going to the new state. */
Reserved = 0x3FFF, /* These bits are reserved and should be set to 0. */
};
inline driver_context_t (const ContextualSubtable *table) :
ret (false),
mark_set (false),
mark (0),
subs (table+table->substitutionTables) {}
inline bool is_actionable (StateTableDriver<EntryData> *driver,
const Entry<EntryData> *entry)
{
hb_buffer_t *buffer = driver->buffer;
if (buffer->idx == buffer->len && !mark_set)
return false;
return entry->data.markIndex != 0xFFFF || entry->data.currentIndex != 0xFFFF;
}
inline bool transition (StateTableDriver<EntryData> *driver,
const Entry<EntryData> *entry)
{
hb_buffer_t *buffer = driver->buffer;
/* Looks like CoreText applies neither mark nor current substitution for
* end-of-text if mark was not explicitly set. */
if (buffer->idx == buffer->len && !mark_set)
return true;
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if (entry->data.markIndex != 0xFFFF)
{
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const Lookup<GlyphID> &lookup = subs[entry->data.markIndex];
hb_glyph_info_t *info = buffer->info;
const GlyphID *replacement = lookup.get_value (info[mark].codepoint, driver->num_glyphs);
if (replacement)
{
buffer->unsafe_to_break (mark, MIN (buffer->idx + 1, buffer->len));
info[mark].codepoint = *replacement;
ret = true;
}
}
if (entry->data.currentIndex != 0xFFFF)
{
unsigned int idx = MIN (buffer->idx, buffer->len - 1);
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const Lookup<GlyphID> &lookup = subs[entry->data.currentIndex];
hb_glyph_info_t *info = buffer->info;
const GlyphID *replacement = lookup.get_value (info[idx].codepoint, driver->num_glyphs);
if (replacement)
{
info[idx].codepoint = *replacement;
ret = true;
}
}
if (entry->flags & SetMark)
{
mark_set = true;
mark = buffer->idx;
}
return true;
}
public:
bool ret;
private:
bool mark_set;
unsigned int mark;
const UnsizedOffsetListOf<Lookup<GlyphID>, HBUINT32> &subs;
};
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inline bool apply (hb_aat_apply_context_t *c) const
{
TRACE_APPLY (this);
driver_context_t dc (this);
StateTableDriver<EntryData> driver (machine, c->buffer, c->face);
driver.drive (&dc);
return_trace (dc.ret);
}
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
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unsigned int num_entries = 0;
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if (unlikely (!machine.sanitize (c, &num_entries))) return_trace (false);
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unsigned int num_lookups = 0;
const Entry<EntryData> *entries = machine.get_entries ();
for (unsigned int i = 0; i < num_entries; i++)
{
const EntryData &data = entries[i].data;
if (data.markIndex != 0xFFFF)
num_lookups = MAX<unsigned int> (num_lookups, 1 + data.markIndex);
if (data.currentIndex != 0xFFFF)
num_lookups = MAX<unsigned int> (num_lookups, 1 + data.currentIndex);
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}
return_trace (substitutionTables.sanitize (c, this, num_lookups));
}
protected:
StateTable<EntryData>
machine;
LOffsetTo<UnsizedOffsetListOf<Lookup<GlyphID>, HBUINT32>, false>
substitutionTables;
public:
DEFINE_SIZE_STATIC (20);
};
struct LigatureSubtable
{
struct EntryData
{
HBUINT16 ligActionIndex; /* Index to the first ligActionTable entry
* for processing this group, if indicated
* by the flags. */
public:
DEFINE_SIZE_STATIC (2);
};
struct driver_context_t
{
static const bool in_place = false;
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enum Flags
{
SetComponent = 0x8000, /* Push this glyph onto the component stack for
* eventual processing. */
DontAdvance = 0x4000, /* Leave the glyph pointer at this glyph for the
next iteration. */
PerformAction = 0x2000, /* Use the ligActionIndex to process a ligature
* group. */
Reserved = 0x1FFF, /* These bits are reserved and should be set to 0. */
};
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enum LigActionFlags
{
LigActionLast = 0x80000000, /* This is the last action in the list. This also
* implies storage. */
LigActionStore = 0x40000000, /* Store the ligature at the current cumulated index
* in the ligature table in place of the marked
* (i.e. currently-popped) glyph. */
LigActionOffset = 0x3FFFFFFF, /* A 30-bit value which is sign-extended to 32-bits
* and added to the glyph ID, resulting in an index
* into the component table. */
};
inline driver_context_t (const LigatureSubtable *table,
hb_aat_apply_context_t *c_) :
ret (false),
c (c_),
ligAction (table+table->ligAction),
component (table+table->component),
ligature (table+table->ligature),
match_length (0) {}
inline bool is_actionable (StateTableDriver<EntryData> *driver,
const Entry<EntryData> *entry)
{
return !!(entry->flags & PerformAction);
}
inline bool transition (StateTableDriver<EntryData> *driver,
const Entry<EntryData> *entry)
{
hb_buffer_t *buffer = driver->buffer;
unsigned int flags = entry->flags;
if (flags & SetComponent)
{
if (unlikely (match_length >= ARRAY_LENGTH (match_positions)))
return false;
/* Never mark same index twice, in case DontAdvance was used... */
if (match_length && match_positions[match_length - 1] == buffer->out_len)
match_length--;
match_positions[match_length++] = buffer->out_len;
}
if (flags & PerformAction)
{
unsigned int end = buffer->out_len;
unsigned int action_idx = entry->data.ligActionIndex;
unsigned int action;
unsigned int ligature_idx = 0;
do
{
if (unlikely (!match_length))
return false;
buffer->move_to (match_positions[--match_length]);
const HBUINT32 &actionData = ligAction[action_idx];
if (unlikely (!actionData.sanitize (&c->sanitizer))) return false;
action = actionData;
uint32_t uoffset = action & LigActionOffset;
if (uoffset & 0x20000000)
uoffset += 0xC0000000;
int32_t offset = (int32_t) uoffset;
unsigned int component_idx = buffer->cur().codepoint + offset;
const HBUINT16 &componentData = component[component_idx];
if (unlikely (!componentData.sanitize (&c->sanitizer))) return false;
ligature_idx += componentData;
if (action & (LigActionStore | LigActionLast))
{
const GlyphID &ligatureData = ligature[ligature_idx];
if (unlikely (!ligatureData.sanitize (&c->sanitizer))) return false;
hb_codepoint_t lig = ligatureData;
match_positions[match_length++] = buffer->out_len;
buffer->replace_glyph (lig);
//ligature_idx = 0; // XXX Yes or no?
}
else
{
buffer->skip_glyph ();
end--;
}
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/* TODO merge_clusters / unsafe_to_break */
action_idx++;
}
while (!(action & LigActionLast));
buffer->move_to (end);
}
return true;
}
public:
bool ret;
private:
hb_aat_apply_context_t *c;
const UnsizedArrayOf<HBUINT32> &ligAction;
const UnsizedArrayOf<HBUINT16> &component;
const UnsizedArrayOf<GlyphID> &ligature;
unsigned int match_length;
unsigned int match_positions[HB_MAX_CONTEXT_LENGTH];
};
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inline bool apply (hb_aat_apply_context_t *c) const
{
TRACE_APPLY (this);
driver_context_t dc (this, c);
StateTableDriver<EntryData> driver (machine, c->buffer, c->face);
driver.drive (&dc);
return_trace (dc.ret);
}
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
/* The rest of array sanitizations are done at run-time. */
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return_trace (c->check_struct (this) && machine.sanitize (c) &&
ligAction && component && ligature);
}
protected:
StateTable<EntryData>
machine;
LOffsetTo<UnsizedArrayOf<HBUINT32>, false>
ligAction; /* Offset to the ligature action table. */
LOffsetTo<UnsizedArrayOf<HBUINT16>, false>
component; /* Offset to the component table. */
LOffsetTo<UnsizedArrayOf<GlyphID>, false>
ligature; /* Offset to the actual ligature lists. */
public:
DEFINE_SIZE_STATIC (28);
};
struct NoncontextualSubtable
{
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inline bool apply (hb_aat_apply_context_t *c) const
{
TRACE_APPLY (this);
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bool ret = false;
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unsigned int num_glyphs = c->face->get_num_glyphs ();
hb_glyph_info_t *info = c->buffer->info;
unsigned int count = c->buffer->len;
for (unsigned int i = 0; i < count; i++)
{
const GlyphID *replacement = substitute.get_value (info[i].codepoint, num_glyphs);
if (replacement)
{
info[i].codepoint = *replacement;
ret = true;
}
}
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return_trace (ret);
}
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (substitute.sanitize (c));
}
protected:
Lookup<GlyphID> substitute;
public:
DEFINE_SIZE_MIN (2);
};
struct InsertionSubtable
{
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struct EntryData
{
HBUINT16 currentInsertIndex; /* Zero-based index into the insertion glyph table.
* The number of glyphs to be inserted is contained
* in the currentInsertCount field in the flags.
* A value of 0xFFFF indicates no insertion is to
* be done. */
HBUINT16 markedInsertIndex; /* Zero-based index into the insertion glyph table.
* The number of glyphs to be inserted is contained
* in the markedInsertCount field in the flags.
* A value of 0xFFFF indicates no insertion is to
* be done. */
public:
DEFINE_SIZE_STATIC (4);
};
struct driver_context_t
{
static const bool in_place = false;
enum Flags
{
SetMark = 0x8000, /* If set, mark the current glyph. */
DontAdvance = 0x4000, /* If set, don't advance to the next glyph before
* going to the new state. This does not mean
* that the glyph pointed to is the same one as
* before. If you've made insertions immediately
* downstream of the current glyph, the next glyph
* processed would in fact be the first one
* inserted. */
CurrentIsKashidaLike= 0x2000, /* If set, and the currentInsertList is nonzero,
* then the specified glyph list will be inserted
* as a kashida-like insertion, either before or
* after the current glyph (depending on the state
* of the currentInsertBefore flag). If clear, and
* the currentInsertList is nonzero, then the
* specified glyph list will be inserted as a
* split-vowel-like insertion, either before or
* after the current glyph (depending on the state
* of the currentInsertBefore flag). */
MarkedIsKashidaLike= 0x1000, /* If set, and the markedInsertList is nonzero,
* then the specified glyph list will be inserted
* as a kashida-like insertion, either before or
* after the marked glyph (depending on the state
* of the markedInsertBefore flag). If clear, and
* the markedInsertList is nonzero, then the
* specified glyph list will be inserted as a
* split-vowel-like insertion, either before or
* after the marked glyph (depending on the state
* of the markedInsertBefore flag). */
CurrentInsertBefore= 0x0800, /* If set, specifies that insertions are to be made
* to the left of the current glyph. If clear,
* they're made to the right of the current glyph. */
MarkedInsertBefore= 0x0400, /* If set, specifies that insertions are to be
* made to the left of the marked glyph. If clear,
* they're made to the right of the marked glyph. */
CurrentInsertCount= 0x3E0, /* This 5-bit field is treated as a count of the
* number of glyphs to insert at the current
* position. Since zero means no insertions, the
* largest number of insertions at any given
* current location is 31 glyphs. */
MarkedInsertCount= 0x001F, /* This 5-bit field is treated as a count of the
* number of glyphs to insert at the marked
* position. Since zero means no insertions, the
* largest number of insertions at any given
* marked location is 31 glyphs. */
};
inline driver_context_t (const InsertionSubtable *table,
hb_aat_apply_context_t *c_) :
ret (false),
c (c_),
mark_set (false),
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mark (0),
insertionAction (table+table->insertionAction) {}
inline bool is_actionable (StateTableDriver<EntryData> *driver,
const Entry<EntryData> *entry)
{
return (entry->flags & (CurrentInsertCount | MarkedInsertCount)) &&
(entry->data.currentInsertIndex != 0xFFFF ||entry->data.markedInsertIndex != 0xFFFF);
}
inline bool transition (StateTableDriver<EntryData> *driver,
const Entry<EntryData> *entry)
{
hb_buffer_t *buffer = driver->buffer;
unsigned int flags = entry->flags;
if (entry->data.markedInsertIndex != 0xFFFF && mark_set)
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{
unsigned int count = (flags & MarkedInsertCount);
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unsigned int start = entry->data.markedInsertIndex;
const GlyphID *glyphs = &insertionAction[start];
if (unlikely (!c->sanitizer.check_array (glyphs, count))) return false;
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bool before = flags & MarkedInsertBefore;
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unsigned int end = buffer->out_len;
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buffer->move_to (mark);
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if (!before)
buffer->copy_glyph ();
/* TODO We ignore KashidaLike setting. */
for (unsigned int i = 0; i < count; i++)
buffer->output_glyph (glyphs[i]);
if (!before)
buffer->skip_glyph ();
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buffer->move_to (end + count);
buffer->unsafe_to_break_from_outbuffer (mark, MIN (buffer->idx + 1, buffer->len));
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}
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if (entry->data.currentInsertIndex != 0xFFFF)
{
unsigned int count = (flags & CurrentInsertCount) >> 5;
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unsigned int start = entry->data.currentInsertIndex;
const GlyphID *glyphs = &insertionAction[start];
if (unlikely (!c->sanitizer.check_array (glyphs, count))) return false;
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bool before = flags & CurrentInsertBefore;
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unsigned int end = buffer->out_len;
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if (!before)
buffer->copy_glyph ();
/* TODO We ignore KashidaLike setting. */
for (unsigned int i = 0; i < count; i++)
buffer->output_glyph (glyphs[i]);
if (!before)
buffer->skip_glyph ();
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/* Humm. Not sure where to move to. There's this wording under
* DontAdvance flag:
*
* "If set, don't update the glyph index before going to the new state.
* This does not mean that the glyph pointed to is the same one as
* before. If you've made insertions immediately downstream of the
* current glyph, the next glyph processed would in fact be the first
* one inserted."
*
* This suggests that if DontAdvance is NOT set, we should move to
* end+count. If it *was*, then move to end, such that newly inserted
* glyphs are now visible.
*
* https://github.com/harfbuzz/harfbuzz/issues/1224#issuecomment-427691417
*/
buffer->move_to ((flags & DontAdvance) ? end : end + count);
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}
if (flags & SetMark)
{
mark_set = true;
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mark = buffer->out_len;
}
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return true;
}
public:
bool ret;
private:
hb_aat_apply_context_t *c;
bool mark_set;
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unsigned int mark;
const UnsizedArrayOf<GlyphID> &insertionAction;
};
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inline bool apply (hb_aat_apply_context_t *c) const
{
TRACE_APPLY (this);
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driver_context_t dc (this, c);
StateTableDriver<EntryData> driver (machine, c->buffer, c->face);
driver.drive (&dc);
return_trace (dc.ret);
}
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
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/* The rest of array sanitizations are done at run-time. */
return_trace (c->check_struct (this) && machine.sanitize (c) &&
insertionAction);
}
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protected:
StateTable<EntryData>
machine;
LOffsetTo<UnsizedArrayOf<GlyphID>, false>
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insertionAction; /* Byte offset from stateHeader to the start of
* the insertion glyph table. */
public:
DEFINE_SIZE_STATIC (20);
};
struct Feature
{
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (c->check_struct (this));
}
public:
HBUINT16 featureType; /* The type of feature. */
HBUINT16 featureSetting; /* The feature's setting (aka selector). */
HBUINT32 enableFlags; /* Flags for the settings that this feature
* and setting enables. */
HBUINT32 disableFlags; /* Complement of flags for the settings that this
* feature and setting disable. */
public:
DEFINE_SIZE_STATIC (12);
};
struct ChainSubtable
{
friend struct Chain;
inline unsigned int get_size (void) const { return length; }
inline unsigned int get_type (void) const { return coverage & SubtableType; }
enum Coverage
{
Vertical = 0x80000000, /* If set, this subtable will only be applied
* to vertical text. If clear, this subtable
* will only be applied to horizontal text. */
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Backwards = 0x40000000, /* If set, this subtable will process glyphs
* in descending order. If clear, it will
* process the glyphs in ascending order. */
AllDirections = 0x20000000, /* If set, this subtable will be applied to
* both horizontal and vertical text (i.e.
* the state of bit 0x80000000 is ignored). */
Logical = 0x10000000, /* If set, this subtable will process glyphs
* in logical order (or reverse logical order,
* depending on the value of bit 0x80000000). */
Reserved = 0x0FFFFF00, /* Reserved, set to zero. */
SubtableType = 0x000000FF, /* Subtable type; see following table. */
};
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enum Type
{
Rearrangement = 0,
Contextual = 1,
Ligature = 2,
Noncontextual = 4,
Insertion = 5
};
template <typename context_t>
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inline typename context_t::return_t dispatch (context_t *c) const
{
unsigned int subtable_type = get_type ();
TRACE_DISPATCH (this, subtable_type);
switch (subtable_type) {
case Rearrangement: return_trace (c->dispatch (u.rearrangement));
case Contextual: return_trace (c->dispatch (u.contextual));
case Ligature: return_trace (c->dispatch (u.ligature));
case Noncontextual: return_trace (c->dispatch (u.noncontextual));
case Insertion: return_trace (c->dispatch (u.insertion));
default: return_trace (c->default_return_value ());
}
}
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
if (!length.sanitize (c) ||
length < min_size ||
!c->check_range (this, length))
return_trace (false);
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return_trace (dispatch (c));
}
protected:
HBUINT32 length; /* Total subtable length, including this header. */
HBUINT32 coverage; /* Coverage flags and subtable type. */
HBUINT32 subFeatureFlags;/* The 32-bit mask identifying which subtable this is. */
union {
RearrangementSubtable rearrangement;
ContextualSubtable contextual;
LigatureSubtable ligature;
NoncontextualSubtable noncontextual;
InsertionSubtable insertion;
} u;
public:
DEFINE_SIZE_MIN (12);
};
struct Chain
{
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inline void apply (hb_aat_apply_context_t *c) const
{
uint32_t flags = defaultFlags;
{
/* Compute applicable flags. TODO Should move this to planning
* stage and take user-requested features into account. */
unsigned int count = featureCount;
for (unsigned i = 0; i < count; i++)
{
const Feature &feature = featureZ[i];
if (false) /* XXX Check if feature enabled... */
{
flags &= feature.disableFlags;
flags |= feature.enableFlags;
}
}
}
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const ChainSubtable *subtable = &StructAtOffset<ChainSubtable> (&featureZ, featureZ[0].static_size * featureCount);
unsigned int count = subtableCount;
for (unsigned int i = 0; i < count; i++)
{
bool reverse;
if (!(subtable->subFeatureFlags & flags))
goto skip;
if (!(subtable->coverage & ChainSubtable::AllDirections) &&
HB_DIRECTION_IS_VERTICAL (c->buffer->props.direction) !=
bool (subtable->coverage & ChainSubtable::Vertical))
goto skip;
/* Buffer contents is always in logical direction. Determine if
* we need to reverse before applying this subtable. We reverse
* back after if we did reverse indeed.
*
* Quoting the spac:
* """
* Bits 28 and 30 of the coverage field control the order in which
* glyphs are processed when the subtable is run by the layout engine.
* Bit 28 is used to indicate if the glyph processing direction is
* the same as logical order or layout order. Bit 30 is used to
* indicate whether glyphs are processed forwards or backwards within
* that order.
Bit 30 Bit 28 Interpretation for Horizontal Text
0 0 The subtable is processed in layout order
(the same order as the glyphs, which is
always left-to-right).
1 0 The subtable is processed in reverse layout order
(the order opposite that of the glyphs, which is
always right-to-left).
0 1 The subtable is processed in logical order
(the same order as the characters, which may be
left-to-right or right-to-left).
1 1 The subtable is processed in reverse logical order
(the order opposite that of the characters, which
may be right-to-left or left-to-right).
*/
reverse = subtable->coverage & ChainSubtable::Logical ?
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bool (subtable->coverage & ChainSubtable::Backwards) :
bool (subtable->coverage & ChainSubtable::Backwards) !=
HB_DIRECTION_IS_BACKWARD (c->buffer->props.direction);
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if (!c->buffer->message (c->font, "start chain subtable %d", c->lookup_index))
goto skip;
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if (reverse)
c->buffer->reverse ();
c->sanitizer.set_object (*subtable);
subtable->dispatch (c);
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if (reverse)
c->buffer->reverse ();
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(void) c->buffer->message (c->font, "end chain subtable %d", c->lookup_index);
if (unlikely (!c->buffer->successful)) return;
skip:
subtable = &StructAfter<ChainSubtable> (*subtable);
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c->set_lookup_index (c->lookup_index + 1);
}
}
inline unsigned int get_size (void) const { return length; }
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inline bool sanitize (hb_sanitize_context_t *c, unsigned int version) const
{
TRACE_SANITIZE (this);
if (!length.sanitize (c) ||
length < min_size ||
!c->check_range (this, length))
return_trace (false);
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if (!c->check_array (featureZ.arrayZ, featureCount))
return_trace (false);
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const ChainSubtable *subtable = &StructAtOffset<ChainSubtable> (&featureZ, featureZ[0].static_size * featureCount);
unsigned int count = subtableCount;
for (unsigned int i = 0; i < count; i++)
{
if (!subtable->sanitize (c))
return_trace (false);
subtable = &StructAfter<ChainSubtable> (*subtable);
}
return_trace (true);
}
protected:
HBUINT32 defaultFlags; /* The default specification for subtables. */
HBUINT32 length; /* Total byte count, including this header. */
HBUINT32 featureCount; /* Number of feature subtable entries. */
HBUINT32 subtableCount; /* The number of subtables in the chain. */
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UnsizedArrayOf<Feature> featureZ; /* Features. */
/*ChainSubtable firstSubtable;*//* Subtables. */
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/*subtableGlyphCoverageArray*/ /* Only if version >= 3. We don't use. */
public:
DEFINE_SIZE_MIN (16);
};
/*
* The 'morx' Table
*/
struct morx
{
static const hb_tag_t tableTag = HB_AAT_TAG_morx;
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inline bool has_data (void) const { return version != 0; }
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inline void apply (hb_aat_apply_context_t *c) const
{
if (unlikely (!c->buffer->successful)) return;
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c->set_lookup_index (0);
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const Chain *chain = &firstChain;
unsigned int count = chainCount;
for (unsigned int i = 0; i < count; i++)
{
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chain->apply (c);
if (unlikely (!c->buffer->successful)) return;
chain = &StructAfter<Chain> (*chain);
}
}
inline bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
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if (!version.sanitize (c) || version < 2 ||
!chainCount.sanitize (c))
return_trace (false);
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const Chain *chain = &firstChain;
unsigned int count = chainCount;
for (unsigned int i = 0; i < count; i++)
{
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if (!chain->sanitize (c, version))
return_trace (false);
chain = &StructAfter<Chain> (*chain);
}
return_trace (true);
}
protected:
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HBUINT16 version; /* Version number of the glyph metamorphosis table.
* 2 or 3. */
HBUINT16 unused; /* Set to 0. */
HBUINT32 chainCount; /* Number of metamorphosis chains contained in this
* table. */
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Chain firstChain; /* Chains. */
public:
DEFINE_SIZE_MIN (8);
};
} /* namespace AAT */
#endif /* HB_AAT_LAYOUT_MORX_TABLE_HH */