harfbuzz/src/hb-ot-var-common.hh

226 lines
6.4 KiB
C++

/*
* Copyright © 2021 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.
*
*/
#ifndef HB_OT_VAR_COMMON_HH
#define HB_OT_VAR_COMMON_HH
#include "hb-ot-layout-common.hh"
namespace OT {
template <typename MapCountT>
struct DeltaSetIndexMapFormat01
{
friend struct DeltaSetIndexMap;
private:
DeltaSetIndexMapFormat01* copy (hb_serialize_context_t *c) const
{
TRACE_SERIALIZE (this);
auto *out = c->start_embed (this);
if (unlikely (!out)) return_trace (nullptr);
unsigned total_size = min_size + mapCount * get_width ();
HBUINT8 *p = c->allocate_size<HBUINT8> (total_size);
if (unlikely (!p)) return_trace (nullptr);
hb_memcpy (p, this, HBUINT8::static_size * total_size);
return_trace (out);
}
template <typename T>
bool serialize (hb_serialize_context_t *c, const T &plan)
{
unsigned int width = plan.get_width ();
unsigned int inner_bit_count = plan.get_inner_bit_count ();
const hb_array_t<const uint32_t> output_map = plan.get_output_map ();
TRACE_SERIALIZE (this);
if (unlikely (output_map.length && ((((inner_bit_count-1)&~0xF)!=0) || (((width-1)&~0x3)!=0))))
return_trace (false);
if (unlikely (!c->extend_min (this))) return_trace (false);
entryFormat = ((width-1)<<4)|(inner_bit_count-1);
mapCount = output_map.length;
HBUINT8 *p = c->allocate_size<HBUINT8> (width * output_map.length);
if (unlikely (!p)) return_trace (false);
for (unsigned int i = 0; i < output_map.length; i++)
{
unsigned int v = output_map[i];
unsigned int outer = v >> 16;
unsigned int inner = v & 0xFFFF;
unsigned int u = (outer << inner_bit_count) | inner;
for (unsigned int w = width; w > 0;)
{
p[--w] = u;
u >>= 8;
}
p += width;
}
return_trace (true);
}
uint32_t map (unsigned int v) const /* Returns 16.16 outer.inner. */
{
/* If count is zero, pass value unchanged. This takes
* care of direct mapping for advance map. */
if (!mapCount)
return v;
if (v >= mapCount)
v = mapCount - 1;
unsigned int u = 0;
{ /* Fetch it. */
unsigned int w = get_width ();
const HBUINT8 *p = mapDataZ.arrayZ + w * v;
for (; w; w--)
u = (u << 8) + *p++;
}
{ /* Repack it. */
unsigned int n = get_inner_bit_count ();
unsigned int outer = u >> n;
unsigned int inner = u & ((1 << n) - 1);
u = (outer<<16) | inner;
}
return u;
}
unsigned get_map_count () const { return mapCount; }
unsigned get_width () const { return ((entryFormat >> 4) & 3) + 1; }
unsigned get_inner_bit_count () const { return (entryFormat & 0xF) + 1; }
bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (c->check_struct (this) &&
c->check_range (mapDataZ.arrayZ,
mapCount,
get_width ()));
}
protected:
HBUINT8 format; /* Format identifier--format = 0 */
HBUINT8 entryFormat; /* A packed field that describes the compressed
* representation of delta-set indices. */
MapCountT mapCount; /* The number of mapping entries. */
UnsizedArrayOf<HBUINT8>
mapDataZ; /* The delta-set index mapping data. */
public:
DEFINE_SIZE_ARRAY (2+MapCountT::static_size, mapDataZ);
};
struct DeltaSetIndexMap
{
template <typename T>
bool serialize (hb_serialize_context_t *c, const T &plan)
{
TRACE_SERIALIZE (this);
unsigned length = plan.get_output_map ().length;
u.format = length <= 0xFFFF ? 0 : 1;
switch (u.format) {
case 0: return_trace (u.format0.serialize (c, plan));
case 1: return_trace (u.format1.serialize (c, plan));
default:return_trace (false);
}
}
uint32_t map (unsigned v) const
{
switch (u.format) {
case 0: return (u.format0.map (v));
case 1: return (u.format1.map (v));
default:return v;
}
}
unsigned get_map_count () const
{
switch (u.format) {
case 0: return u.format0.get_map_count ();
case 1: return u.format1.get_map_count ();
default:return 0;
}
}
unsigned get_width () const
{
switch (u.format) {
case 0: return u.format0.get_width ();
case 1: return u.format1.get_width ();
default:return 0;
}
}
unsigned get_inner_bit_count () const
{
switch (u.format) {
case 0: return u.format0.get_inner_bit_count ();
case 1: return u.format1.get_inner_bit_count ();
default:return 0;
}
}
bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
if (!u.format.sanitize (c)) return_trace (false);
switch (u.format) {
case 0: return_trace (u.format0.sanitize (c));
case 1: return_trace (u.format1.sanitize (c));
default:return_trace (true);
}
}
DeltaSetIndexMap* copy (hb_serialize_context_t *c) const
{
TRACE_SERIALIZE (this);
switch (u.format) {
case 0: return_trace (reinterpret_cast<DeltaSetIndexMap *> (u.format0.copy (c)));
case 1: return_trace (reinterpret_cast<DeltaSetIndexMap *> (u.format1.copy (c)));
default:return_trace (nullptr);
}
}
protected:
union {
HBUINT8 format; /* Format identifier */
DeltaSetIndexMapFormat01<HBUINT16> format0;
DeltaSetIndexMapFormat01<HBUINT32> format1;
} u;
public:
DEFINE_SIZE_UNION (1, format);
};
} /* namespace OT */
#endif /* HB_OT_VAR_COMMON_HH */