/*
* Copyright © 2018 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): Garret Rieger, Roderick Sheeter
*/
#ifndef HB_SUBSET_TABLE_HH
#define HB_SUBSET_TABLE_HH
#include "hb.hh"
#include "hb-subset.hh"
#include "hb-repacker.hh"
template<typename TableType>
static bool
_hb_subset_table_try (const TableType *table,
hb_vector_t<char>* buf,
hb_subset_context_t* c /* OUT */)
{
c->serializer->start_serialize ();
if (c->serializer->in_error ()) return false;
bool needed = table->subset (c);
if (!c->serializer->ran_out_of_room ())
{
c->serializer->end_serialize ();
return needed;
}
unsigned buf_size = buf->allocated;
buf_size = buf_size * 2 + 16;
DEBUG_MSG (SUBSET, nullptr, "OT::%c%c%c%c ran out of room; reallocating to %u bytes.",
HB_UNTAG (c->table_tag), buf_size);
if (unlikely (buf_size > c->source_blob->length * 256 ||
!buf->alloc_exact (buf_size)))
{
DEBUG_MSG (SUBSET, nullptr, "OT::%c%c%c%c failed to reallocate %u bytes.",
HB_UNTAG (c->table_tag), buf_size);
return needed;
}
c->serializer->reset (buf->arrayZ, buf->allocated);
return _hb_subset_table_try (table, buf, c);
}
static HB_UNUSED unsigned
_hb_subset_estimate_table_size (hb_subset_plan_t *plan,
unsigned table_len,
hb_tag_t table_tag)
{
unsigned src_glyphs = plan->source->get_num_glyphs ();
unsigned dst_glyphs = plan->glyphset ()->get_population ();
unsigned bulk = 8192;
/* Tables that we want to allocate same space as the source table. For GSUB/GPOS it's
* because those are expensive to subset, so giving them more room is fine. */
bool same_size = table_tag == HB_TAG('G','S','U','B') ||
table_tag == HB_TAG('G','P','O','S') ||
table_tag == HB_TAG('G','D','E','F') ||
table_tag == HB_TAG('n','a','m','e');
if (plan->flags & HB_SUBSET_FLAGS_RETAIN_GIDS)
{
if (table_tag == HB_TAG('C','F','F',' '))
{
/* Add some extra room for the CFF charset. */
bulk += src_glyphs * 16;
}
else if (table_tag == HB_TAG('C','F','F','2'))
{
/* Just extra CharString offsets. */
bulk += src_glyphs * 4;
}
}
if (unlikely (!src_glyphs) || same_size)
return bulk + table_len;
return bulk + (unsigned) (table_len * sqrt ((double) dst_glyphs / src_glyphs));
}
/*
* Repack the serialization buffer if any offset overflows exist.
*/
static HB_UNUSED hb_blob_t*
_hb_subset_repack (hb_tag_t tag, const hb_serialize_context_t& c)
{
if (!c.offset_overflow ())
return c.copy_blob ();
hb_blob_t* result = hb_resolve_overflows (c.object_graph (), tag);
if (unlikely (!result))
{
DEBUG_MSG (SUBSET, nullptr, "OT::%c%c%c%c offset overflow resolution failed.",
HB_UNTAG (tag));
return nullptr;
}
return result;
}
template <typename T>
static HB_UNUSED auto _hb_do_destroy (T &t, hb_priority<1>) HB_RETURN (void, t.destroy ())
template <typename T>
static HB_UNUSED void _hb_do_destroy (T &t, hb_priority<0>) {}
template<typename TableType>
static bool
_hb_subset_table (hb_subset_plan_t *plan, hb_vector_t<char> &buf)
{
auto &&source_blob = plan->source_table<TableType> ();
auto *table = source_blob.get ();
hb_tag_t tag = TableType::tableTag;
hb_blob_t *blob = source_blob.get_blob();
if (unlikely (!blob || !blob->data))
{
DEBUG_MSG (SUBSET, nullptr,
"OT::%c%c%c%c::subset sanitize failed on source table.", HB_UNTAG (tag));
_hb_do_destroy (source_blob, hb_prioritize);
return false;
}
unsigned buf_size = _hb_subset_estimate_table_size (plan, blob->length, TableType::tableTag);
DEBUG_MSG (SUBSET, nullptr,
"OT::%c%c%c%c initial estimated table size: %u bytes.", HB_UNTAG (tag), buf_size);
if (unlikely (!buf.alloc (buf_size)))
{
DEBUG_MSG (SUBSET, nullptr, "OT::%c%c%c%c failed to allocate %u bytes.", HB_UNTAG (tag), buf_size);
_hb_do_destroy (source_blob, hb_prioritize);
return false;
}
bool needed = false;
hb_serialize_context_t serializer (buf.arrayZ, buf.allocated);
{
hb_subset_context_t c (blob, plan, &serializer, tag);
needed = _hb_subset_table_try (table, &buf, &c);
}
_hb_do_destroy (source_blob, hb_prioritize);
if (serializer.in_error () && !serializer.only_offset_overflow ())
{
DEBUG_MSG (SUBSET, nullptr, "OT::%c%c%c%c::subset FAILED!", HB_UNTAG (tag));
return false;
}
if (!needed)
{
DEBUG_MSG (SUBSET, nullptr, "OT::%c%c%c%c::subset table subsetted to empty.", HB_UNTAG (tag));
return true;
}
bool result = false;
hb_blob_t *dest_blob = _hb_subset_repack (tag, serializer);
if (dest_blob)
{
DEBUG_MSG (SUBSET, nullptr,
"OT::%c%c%c%c final subset table size: %u bytes.",
HB_UNTAG (tag), dest_blob->length);
result = plan->add_table (tag, dest_blob);
hb_blob_destroy (dest_blob);
}
DEBUG_MSG (SUBSET, nullptr, "OT::%c%c%c%c::subset %s",
HB_UNTAG (tag), result ? "success" : "FAILED!");
return result;
}
static HB_UNUSED bool
_hb_subset_table_passthrough (hb_subset_plan_t *plan, hb_tag_t tag)
{
hb_blob_t *source_table = hb_face_reference_table (plan->source, tag);
bool result = plan->add_table (tag, source_table);
hb_blob_destroy (source_table);
return result;
}
HB_INTERNAL bool _hb_subset_table_layout (hb_subset_plan_t *plan, hb_vector_t<char> &buf, hb_tag_t tag, bool *success);
HB_INTERNAL bool _hb_subset_table_var (hb_subset_plan_t *plan, hb_vector_t<char> &buf, hb_tag_t tag, bool *success);
HB_INTERNAL bool _hb_subset_table_cff (hb_subset_plan_t *plan, hb_vector_t<char> &buf, hb_tag_t tag, bool *success);
HB_INTERNAL bool _hb_subset_table_color (hb_subset_plan_t *plan, hb_vector_t<char> &buf, hb_tag_t tag, bool *success);
HB_INTERNAL bool _hb_subset_table_other (hb_subset_plan_t *plan, hb_vector_t<char> &buf, hb_tag_t tag, bool *success);
#endif /* HB_SUBSET_TABLE_HH */
