/*

 * 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, Rod Sheeter, Behdad Esfahbod

 */

#include "hb.hh"

#include "hb-open-type.hh"

#include "hb-subset.hh"

#include "hb-open-file.hh"

#include "hb-ot-cmap-table.hh"

#include "hb-ot-glyf-table.hh"

#include "hb-ot-hdmx-table.hh"

#include "hb-ot-head-table.hh"

#include "hb-ot-hhea-table.hh"

#include "hb-ot-hmtx-table.hh"

#include "hb-ot-maxp-table.hh"

#include "hb-ot-color-sbix-table.hh"

#include "hb-ot-color-colr-table.hh"

#include "hb-ot-color-cpal-table.hh"

#include "hb-ot-os2-table.hh"

#include "hb-ot-post-table.hh"

#include "hb-ot-post-table-v2subset.hh"

#include "hb-ot-cff1-table.hh"

#include "hb-ot-cff2-table.hh"

#include "hb-ot-vorg-table.hh"

#include "hb-ot-name-table.hh"

#include "hb-ot-color-cbdt-table.hh"

#include "hb-ot-layout-gsub-table.hh"

#include "hb-ot-layout-gpos-table.hh"

#include "hb-ot-var-gvar-table.hh"

#include "hb-ot-var-hvar-table.hh"

#include "hb-repacker.hh"

/**

 * SECTION:hb-subset

 * @title: hb-subset

 * @short_description: Subsets font files.

 * @include: hb-subset.h

 *

 * Subsetting reduces the codepoint coverage of font files and removes all data

 * that is no longer needed. A subset input describes the desired subset. The input is

 * provided along with a font to the subsetting operation. Output is a new font file

 * containing only the data specified in the input.

 *

 * Currently most outline and bitmap tables are supported: glyf, CFF, CFF2, sbix,

 * COLR, and CBDT/CBLC. This also includes fonts with variable outlines via OpenType

 * variations. Notably EBDT/EBLC and SVG are not supported. Layout subsetting is supported

 * only for OpenType Layout tables (GSUB, GPOS, GDEF). Notably subsetting of graphite or AAT tables

 * is not yet supported.

 *

 * Fonts with graphite or AAT tables may still be subsetted but will likely need to use the

 * retain glyph ids option and configure the subset to pass through the layout tables untouched.

 */

static unsigned

_plan_estimate_subset_table_size (hb_subset_plan_t *plan, unsigned table_len)

{

  unsigned src_glyphs = plan->source->get_num_glyphs ();

  unsigned dst_glyphs = plan->glyphset ()->get_population ();

  if (unlikely (!src_glyphs))

    return 512 + table_len;

  return 512 + (unsigned) (table_len * sqrt ((double) dst_glyphs / src_glyphs));

}

/*

 * Repack the serialization buffer if any offset overflows exist.

 */

static hb_blob_t*

_repack (hb_tag_t tag, const hb_serialize_context_t& c)

{

  if (tag != HB_OT_TAG_GPOS

      &&  tag != HB_OT_TAG_GSUB)

  {

    // Check for overflow in a non-handled table.

    return c.successful () ? c.copy_blob () : nullptr;

  }

  if (!c.offset_overflow ())

    return c.copy_blob ();

  hb_vector_t<char> buf;

  int buf_size = c.end - c.start;

  if (unlikely (!buf.alloc (buf_size)))

    return nullptr;

  hb_serialize_context_t repacked ((void *) buf, buf_size);

  hb_resolve_overflows (c.object_graph (), &repacked);

  if (unlikely (repacked.in_error ()))

    // TODO(garretrieger): refactor so we can share the resize/retry logic with the subset

    //                     portion.

    return nullptr;

  return repacked.copy_blob ();

}

template<typename TableType>

static

bool

_try_subset (const TableType *table,

             hb_vector_t<char>* buf,

             unsigned buf_size,

             hb_subset_context_t* c /* OUT */)

{

  c->serializer->start_serialize<TableType> ();

  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;

  }

  buf_size += (buf_size >> 1) + 32;

  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->alloc (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_size);

  return _try_subset (table, buf, buf_size, c);

}

Unexecuted instantiation: hb-subset.cc:bool _try_subset<OT::glyf>(OT::glyf const*, hb_vector_t<char>*, unsigned int, hb_subset_context_t*)

Unexecuted instantiation: hb-subset.cc:bool _try_subset<OT::hdmx>(OT::hdmx const*, hb_vector_t<char>*, unsigned int, hb_subset_context_t*)

Unexecuted instantiation: hb-subset.cc:bool _try_subset<OT::name>(OT::name const*, hb_vector_t<char>*, unsigned int, hb_subset_context_t*)

Unexecuted instantiation: hb-subset.cc:bool _try_subset<OT::head>(OT::head const*, hb_vector_t<char>*, unsigned int, hb_subset_context_t*)

Unexecuted instantiation: hb-subset.cc:bool _try_subset<OT::hmtx>(OT::hmtx const*, hb_vector_t<char>*, unsigned int, hb_subset_context_t*)

Unexecuted instantiation: hb-subset.cc:bool _try_subset<OT::vmtx>(OT::vmtx const*, hb_vector_t<char>*, unsigned int, hb_subset_context_t*)

Unexecuted instantiation: hb-subset.cc:bool _try_subset<OT::maxp>(OT::maxp const*, hb_vector_t<char>*, unsigned int, hb_subset_context_t*)

Unexecuted instantiation: hb-subset.cc:bool _try_subset<OT::sbix>(OT::sbix const*, hb_vector_t<char>*, unsigned int, hb_subset_context_t*)

Unexecuted instantiation: hb-subset.cc:bool _try_subset<OT::cmap>(OT::cmap const*, hb_vector_t<char>*, unsigned int, hb_subset_context_t*)

Unexecuted instantiation: hb-subset.cc:bool _try_subset<OT::OS2>(OT::OS2 const*, hb_vector_t<char>*, unsigned int, hb_subset_context_t*)

Unexecuted instantiation: hb-subset.cc:bool _try_subset<OT::post>(OT::post const*, hb_vector_t<char>*, unsigned int, hb_subset_context_t*)

Unexecuted instantiation: hb-subset.cc:bool _try_subset<OT::COLR>(OT::COLR const*, hb_vector_t<char>*, unsigned int, hb_subset_context_t*)

Unexecuted instantiation: hb-subset.cc:bool _try_subset<OT::CPAL>(OT::CPAL const*, hb_vector_t<char>*, unsigned int, hb_subset_context_t*)

Unexecuted instantiation: hb-subset.cc:bool _try_subset<OT::CBLC>(OT::CBLC const*, hb_vector_t<char>*, unsigned int, hb_subset_context_t*)

Unexecuted instantiation: hb-subset.cc:bool _try_subset<OT::cff1>(OT::cff1 const*, hb_vector_t<char>*, unsigned int, hb_subset_context_t*)

Unexecuted instantiation: hb-subset.cc:bool _try_subset<OT::cff2>(OT::cff2 const*, hb_vector_t<char>*, unsigned int, hb_subset_context_t*)

Unexecuted instantiation: hb-subset.cc:bool _try_subset<OT::VORG>(OT::VORG const*, hb_vector_t<char>*, unsigned int, hb_subset_context_t*)

Unexecuted instantiation: hb-subset.cc:bool _try_subset<OT::GDEF>(OT::GDEF const*, hb_vector_t<char>*, unsigned int, hb_subset_context_t*)

Unexecuted instantiation: hb-subset.cc:bool _try_subset<OT::GSUB>(OT::GSUB const*, hb_vector_t<char>*, unsigned int, hb_subset_context_t*)

Unexecuted instantiation: hb-subset.cc:bool _try_subset<OT::GPOS>(OT::GPOS const*, hb_vector_t<char>*, unsigned int, hb_subset_context_t*)

Unexecuted instantiation: hb-subset.cc:bool _try_subset<OT::gvar>(OT::gvar const*, hb_vector_t<char>*, unsigned int, hb_subset_context_t*)

Unexecuted instantiation: hb-subset.cc:bool _try_subset<OT::HVAR>(OT::HVAR const*, hb_vector_t<char>*, unsigned int, hb_subset_context_t*)

Unexecuted instantiation: hb-subset.cc:bool _try_subset<OT::VVAR>(OT::VVAR const*, hb_vector_t<char>*, unsigned int, hb_subset_context_t*)

template<typename TableType>

static bool

_subset (hb_subset_plan_t *plan)

{

  hb_blob_t *source_blob = hb_sanitize_context_t ().reference_table<TableType> (plan->source);

  const TableType *table = source_blob->as<TableType> ();

  hb_tag_t tag = TableType::tableTag;

  if (!source_blob->data)

  {

    DEBUG_MSG (SUBSET, nullptr,

               "OT::%c%c%c%c::subset sanitize failed on source table.", HB_UNTAG (tag));

    hb_blob_destroy (source_blob);

    return false;

  }

  hb_vector_t<char> buf;

  /* TODO Not all tables are glyph-related.  'name' table size for example should not be

   * affected by number of glyphs.  Accommodate that. */

  unsigned buf_size = _plan_estimate_subset_table_size (plan, source_blob->length);

  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_blob_destroy (source_blob);

    return false;

  }

  bool needed = false;

  hb_serialize_context_t serializer (buf.arrayZ, buf_size);

  {

    hb_subset_context_t c (source_blob, plan, &serializer, tag);

    needed = _try_subset (table, &buf, buf_size, &c);

  }

  hb_blob_destroy (source_blob);

  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 = _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;

}

Unexecuted instantiation: hb-subset.cc:bool _subset<OT::glyf const>(hb_subset_plan_t*)

Unexecuted instantiation: hb-subset.cc:bool _subset<OT::hdmx const>(hb_subset_plan_t*)

Unexecuted instantiation: hb-subset.cc:bool _subset<OT::name const>(hb_subset_plan_t*)

Unexecuted instantiation: hb-subset.cc:bool _subset<OT::head const>(hb_subset_plan_t*)

Unexecuted instantiation: hb-subset.cc:bool _subset<OT::hmtx const>(hb_subset_plan_t*)

Unexecuted instantiation: hb-subset.cc:bool _subset<OT::vmtx const>(hb_subset_plan_t*)

Unexecuted instantiation: hb-subset.cc:bool _subset<OT::maxp const>(hb_subset_plan_t*)

Unexecuted instantiation: hb-subset.cc:bool _subset<OT::sbix const>(hb_subset_plan_t*)

Unexecuted instantiation: hb-subset.cc:bool _subset<OT::cmap const>(hb_subset_plan_t*)

Unexecuted instantiation: hb-subset.cc:bool _subset<OT::OS2 const>(hb_subset_plan_t*)

Unexecuted instantiation: hb-subset.cc:bool _subset<OT::post const>(hb_subset_plan_t*)

Unexecuted instantiation: hb-subset.cc:bool _subset<OT::COLR const>(hb_subset_plan_t*)

Unexecuted instantiation: hb-subset.cc:bool _subset<OT::CPAL const>(hb_subset_plan_t*)

Unexecuted instantiation: hb-subset.cc:bool _subset<OT::CBLC const>(hb_subset_plan_t*)

Unexecuted instantiation: hb-subset.cc:bool _subset<OT::cff1 const>(hb_subset_plan_t*)

Unexecuted instantiation: hb-subset.cc:bool _subset<OT::cff2 const>(hb_subset_plan_t*)

Unexecuted instantiation: hb-subset.cc:bool _subset<OT::VORG const>(hb_subset_plan_t*)

Unexecuted instantiation: hb-subset.cc:bool _subset<OT::GDEF const>(hb_subset_plan_t*)

Unexecuted instantiation: hb-subset.cc:bool _subset<OT::GSUB const>(hb_subset_plan_t*)

Unexecuted instantiation: hb-subset.cc:bool _subset<OT::GPOS const>(hb_subset_plan_t*)

Unexecuted instantiation: hb-subset.cc:bool _subset<OT::gvar const>(hb_subset_plan_t*)

Unexecuted instantiation: hb-subset.cc:bool _subset<OT::HVAR const>(hb_subset_plan_t*)

Unexecuted instantiation: hb-subset.cc:bool _subset<OT::VVAR const>(hb_subset_plan_t*)

static bool

_is_table_present (hb_face_t *source, hb_tag_t tag)

{

  hb_tag_t table_tags[32];

  unsigned offset = 0, num_tables = ARRAY_LENGTH (table_tags);

  while ((hb_face_get_table_tags (source, offset, &num_tables, table_tags), num_tables))

  {

    for (unsigned i = 0; i < num_tables; ++i)

      if (table_tags[i] == tag)

  return true;

    offset += num_tables;

  }

  return false;

}

static bool

_should_drop_table (hb_subset_plan_t *plan, hb_tag_t tag)

{

  if (plan->drop_tables->has (tag))

    return true;

  switch (tag)

  {

  case HB_TAG ('c','v','a','r'): /* hint table, fallthrough */

  case HB_TAG ('c','v','t',' '): /* hint table, fallthrough */

  case HB_TAG ('f','p','g','m'): /* hint table, fallthrough */

  case HB_TAG ('p','r','e','p'): /* hint table, fallthrough */

  case HB_TAG ('h','d','m','x'): /* hint table, fallthrough */

  case HB_TAG ('V','D','M','X'): /* hint table, fallthrough */

    return plan->flags & HB_SUBSET_FLAGS_NO_HINTING;

#ifdef HB_NO_SUBSET_LAYOUT

    // Drop Layout Tables if requested.

  case HB_OT_TAG_GDEF:

  case HB_OT_TAG_GPOS:

  case HB_OT_TAG_GSUB:

  case HB_TAG ('m','o','r','x'):

  case HB_TAG ('m','o','r','t'):

  case HB_TAG ('k','e','r','x'):

  case HB_TAG ('k','e','r','n'):

    return true;

#endif

  default:

    return false;

  }

}

static bool

_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;

}

static bool

_subset_table (hb_subset_plan_t *plan, hb_tag_t tag)

{

  if (plan->no_subset_tables->has (tag)) {

    return _passthrough (plan, tag);

  }

  DEBUG_MSG (SUBSET, nullptr, "subset %c%c%c%c", HB_UNTAG (tag));

  switch (tag)

  {

  case HB_OT_TAG_glyf: return _subset<const OT::glyf> (plan);

  case HB_OT_TAG_hdmx: return _subset<const OT::hdmx> (plan);

  case HB_OT_TAG_name: return _subset<const OT::name> (plan);

  case HB_OT_TAG_head:

    if (_is_table_present (plan->source, HB_OT_TAG_glyf) && !_should_drop_table (plan, HB_OT_TAG_glyf))

      return true; /* skip head, handled by glyf */

    return _subset<const OT::head> (plan);

  case HB_OT_TAG_hhea: return true; /* skip hhea, handled by hmtx */

  case HB_OT_TAG_hmtx: return _subset<const OT::hmtx> (plan);

  case HB_OT_TAG_vhea: return true; /* skip vhea, handled by vmtx */

  case HB_OT_TAG_vmtx: return _subset<const OT::vmtx> (plan);

  case HB_OT_TAG_maxp: return _subset<const OT::maxp> (plan);

  case HB_OT_TAG_sbix: return _subset<const OT::sbix> (plan);

  case HB_OT_TAG_loca: return true; /* skip loca, handled by glyf */

  case HB_OT_TAG_cmap: return _subset<const OT::cmap> (plan);

  case HB_OT_TAG_OS2 : return _subset<const OT::OS2 > (plan);

  case HB_OT_TAG_post: return _subset<const OT::post> (plan);

  case HB_OT_TAG_COLR: return _subset<const OT::COLR> (plan);

  case HB_OT_TAG_CPAL: return _subset<const OT::CPAL> (plan);

  case HB_OT_TAG_CBLC: return _subset<const OT::CBLC> (plan);

  case HB_OT_TAG_CBDT: return true; /* skip CBDT, handled by CBLC */

#ifndef HB_NO_SUBSET_CFF

  case HB_OT_TAG_cff1: return _subset<const OT::cff1> (plan);

  case HB_OT_TAG_cff2: return _subset<const OT::cff2> (plan);

  case HB_OT_TAG_VORG: return _subset<const OT::VORG> (plan);

#endif

#ifndef HB_NO_SUBSET_LAYOUT

  case HB_OT_TAG_GDEF: return _subset<const OT::GDEF> (plan);

  case HB_OT_TAG_GSUB: return _subset<const OT::GSUB> (plan);

  case HB_OT_TAG_GPOS: return _subset<const OT::GPOS> (plan);

  case HB_OT_TAG_gvar: return _subset<const OT::gvar> (plan);

  case HB_OT_TAG_HVAR: return _subset<const OT::HVAR> (plan);

  case HB_OT_TAG_VVAR: return _subset<const OT::VVAR> (plan);

#endif

  default:

    if (plan->flags & HB_SUBSET_FLAGS_PASSTHROUGH_UNRECOGNIZED)

      return _passthrough (plan, tag);

    // Drop table

    return true;

  }

}

/**

 * hb_subset_or_fail:

 * @source: font face data to be subset.

 * @input: input to use for the subsetting.

 *

 * Subsets a font according to provided input. Returns nullptr

 * if the subset operation fails.

 *

 * Since: REPLACE

 **/

hb_face_t *

hb_subset_or_fail (hb_face_t *source, const hb_subset_input_t *input)

{

  if (unlikely (!input || !source)) return hb_face_get_empty ();

  hb_subset_plan_t *plan = hb_subset_plan_create (source, input);

  if (unlikely (plan->in_error ())) {

    hb_subset_plan_destroy (plan);

    return nullptr;

  }

  hb_set_t tags_set;

  bool success = true;

  hb_tag_t table_tags[32];

  unsigned offset = 0, num_tables = ARRAY_LENGTH (table_tags);

  while ((hb_face_get_table_tags (source, offset, &num_tables, table_tags), num_tables))

  {

    for (unsigned i = 0; i < num_tables; ++i)

    {

      hb_tag_t tag = table_tags[i];

      if (_should_drop_table (plan, tag) && !tags_set.has (tag)) continue;

      tags_set.add (tag);

      success = _subset_table (plan, tag);

      if (unlikely (!success)) goto end;

    }

    offset += num_tables;

  }

end:

  hb_face_t *result = success ? hb_face_reference (plan->dest) : nullptr;

  hb_subset_plan_destroy (plan);

  return result;

}