src/hb-subset-cff-common.cc - third_party/harfbuzz - Git at Google

 /*
  * Copyright © 2018 Adobe 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.
  *
  * Adobe Author(s): Michiharu Ariza
  */

 #include "hb.hh"

 #ifndef HB_NO_SUBSET_CFF

 #include "hb-ot-cff-common.hh"
 #include "hb-ot-cff2-table.hh"
 #include "hb-subset-cff-common.hh"

 /* Disable FDSelect format 0 for compatibility with fonttools which doesn't seem choose it.
  * Rarely any/much smaller than format 3 anyway. */
 #define CFF_SERIALIZE_FDSELECT_0  0

 using namespace CFF;


 /* Determine an optimal FDSelect format according to a provided plan.
  *
  * Return value: FDSelect format, size, and ranges for the most compact subset FDSelect
  * along with a font index remapping table
  */

 bool
 hb_plan_subset_cff_fdselect (const hb_subset_plan_t *plan,
 			     unsigned int fdCount,
 			     const FDSelect &src, /* IN */
 			     unsigned int &subset_fd_count /* OUT */,
 			     unsigned int &subset_fdselect_size /* OUT */,
 			     unsigned int &subset_fdselect_format /* OUT */,
 			     hb_vector_t<code_pair_t> &fdselect_ranges /* OUT */,
 			     hb_inc_bimap_t &fdmap /* OUT */)
 {
   subset_fd_count = 0;
   subset_fdselect_size = 0;
   subset_fdselect_format = 0;
   unsigned int num_ranges = 0;

   unsigned int subset_num_glyphs = plan->num_output_glyphs ();
   if (subset_num_glyphs == 0)
     return true;

   {
     /* use hb_set to determine the subset of font dicts */
     hb_set_t set;
     hb_codepoint_t prev_fd = CFF_UNDEF_CODE;
     hb_pair_t<unsigned, hb_codepoint_t> last_range {0, 0};
     auto it = hb_iter (plan->new_to_old_gid_list);
     auto _ = *it;
     for (hb_codepoint_t gid = 0; gid < subset_num_glyphs; gid++)
     {
       hb_codepoint_t old_glyph;
       if (gid == _.first)
       {
 	old_glyph = _.second;
 	_ = *++it;
       }
       else
       {
 	/* fonttools retains FDSelect & font dicts for missing glyphs. do the same */
 	old_glyph = gid;
       }
       if (old_glyph >= last_range.second)
 	last_range = src.get_fd_range (old_glyph);
       unsigned fd = last_range.first;

       if (fd != prev_fd)
       {
 	set.add (fd);
 	num_ranges++;
 	prev_fd = fd;
 	fdselect_ranges.push (code_pair_t { fd, gid });

 	if (gid == old_glyph)
 	  gid = hb_min (_.first - 1, last_range.second - 1);
       }
     }

     subset_fd_count = set.get_population ();
     if (subset_fd_count == fdCount)
     {
       /* all font dicts belong to the subset. no need to subset FDSelect & FDArray */
       fdmap.identity (fdCount);
     }
     else
     {
       /* create a fdmap */
       fdmap.reset ();

       hb_codepoint_t fd = CFF_UNDEF_CODE;
       while (set.next (&fd))
 	fdmap.add (fd);
       if (unlikely (fdmap.get_population () != subset_fd_count))
 	return false;
     }

     /* update each font dict index stored as "code" in fdselect_ranges */
     for (unsigned int i = 0; i < fdselect_ranges.length; i++)
       fdselect_ranges[i].code = fdmap[fdselect_ranges[i].code];
   }

   /* determine which FDSelect format is most compact */
   if (subset_fd_count > 0xFF)
   {
     if (unlikely (src.format != 4))
       return false;
     subset_fdselect_format = 4;
     subset_fdselect_size = FDSelect::min_size + FDSelect4::min_size + FDSelect4_Range::static_size * num_ranges + HBUINT32::static_size;
   }
   else
   {
 #if CFF_SERIALIZE_FDSELECT_0
     unsigned int format0_size = FDSelect::min_size + FDSelect0::min_size + HBUINT8::static_size * subset_num_glyphs;
 #endif
     unsigned int format3_size = FDSelect::min_size + FDSelect3::min_size + FDSelect3_Range::static_size * num_ranges + HBUINT16::static_size;

 #if CFF_SERIALIZE_FDSELECT_0
     if (format0_size <= format3_size)
     {
       // subset_fdselect_format = 0;
       subset_fdselect_size = format0_size;
     }
     else
 #endif
     {
       subset_fdselect_format = 3;
       subset_fdselect_size = format3_size;
     }
   }

   return true;
 }

 template <typename FDSELECT3_4>
 static inline bool
 serialize_fdselect_3_4 (hb_serialize_context_t *c,
 			const unsigned int num_glyphs,
 			const FDSelect &src,
 			unsigned int size,
 			const hb_vector_t<code_pair_t> &fdselect_ranges)
 {
   TRACE_SERIALIZE (this);
   FDSELECT3_4 *p = c->allocate_size<FDSELECT3_4> (size);
   if (unlikely (!p)) return_trace (false);
   p->nRanges () = fdselect_ranges.length;
   for (unsigned int i = 0; i < fdselect_ranges.length; i++)
   {
     p->ranges[i].first = fdselect_ranges[i].glyph;
     p->ranges[i].fd = fdselect_ranges[i].code;
   }
   p->sentinel () = num_glyphs;
   return_trace (true);
 }

 /* Serialize a subset FDSelect format planned above. */
 bool
 hb_serialize_cff_fdselect (hb_serialize_context_t *c,
 			   const unsigned int num_glyphs,
 			   const FDSelect &src,
 			   unsigned int fd_count,
 			   unsigned int fdselect_format,
 			   unsigned int size,
 			   const hb_vector_t<code_pair_t> &fdselect_ranges)
 {
   TRACE_SERIALIZE (this);
   FDSelect *p = c->allocate_min<FDSelect> ();
   if (unlikely (!p)) return_trace (false);
   p->format = fdselect_format;
   size -= FDSelect::min_size;

   switch (fdselect_format)
   {
 #if CFF_SERIALIZE_FDSELECT_0
   case 0:
   {
     FDSelect0 *p = c->allocate_size<FDSelect0> (size);
     if (unlikely (!p)) return_trace (false);
     unsigned int range_index = 0;
     unsigned int fd = fdselect_ranges[range_index++].code;
     for (unsigned int i = 0; i < num_glyphs; i++)
     {
       if ((range_index < fdselect_ranges.len) &&
 	  (i >= fdselect_ranges[range_index].glyph))
       {
 	fd = fdselect_ranges[range_index++].code;
       }
       p->fds[i] = fd;
     }
     return_trace (true);
   }
 #endif /* CFF_SERIALIZE_FDSELECT_0 */

   case 3:
     return serialize_fdselect_3_4<FDSelect3> (c, num_glyphs, src,
 					      size, fdselect_ranges);

   case 4:
     return serialize_fdselect_3_4<FDSelect4> (c, num_glyphs, src,
 					      size, fdselect_ranges);

   default:
     return_trace (false);
   }
 }


 #endif
	/*
	* Copyright © 2018 Adobe 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.
	*
	* Adobe Author(s): Michiharu Ariza
	*/

	#include "hb.hh"

	#ifndef HB_NO_SUBSET_CFF

	#include "hb-ot-cff-common.hh"
	#include "hb-ot-cff2-table.hh"
	#include "hb-subset-cff-common.hh"

	/* Disable FDSelect format 0 for compatibility with fonttools which doesn't seem choose it.
	* Rarely any/much smaller than format 3 anyway. */
	#define CFF_SERIALIZE_FDSELECT_0 0

	using namespace CFF;


	/* Determine an optimal FDSelect format according to a provided plan.
	*
	* Return value: FDSelect format, size, and ranges for the most compact subset FDSelect
	* along with a font index remapping table
	*/

	bool
	hb_plan_subset_cff_fdselect (const hb_subset_plan_t *plan,
	unsigned int fdCount,
	const FDSelect &src, /* IN */
	unsigned int &subset_fd_count /* OUT */,
	unsigned int &subset_fdselect_size /* OUT */,
	unsigned int &subset_fdselect_format /* OUT */,
	hb_vector_t<code_pair_t> &fdselect_ranges /* OUT */,
	hb_inc_bimap_t &fdmap /* OUT */)
	{
	subset_fd_count = 0;
	subset_fdselect_size = 0;
	subset_fdselect_format = 0;
	unsigned int num_ranges = 0;

	unsigned int subset_num_glyphs = plan->num_output_glyphs ();
	if (subset_num_glyphs == 0)
	return true;

	{
	/* use hb_set to determine the subset of font dicts */
	hb_set_t set;
	hb_codepoint_t prev_fd = CFF_UNDEF_CODE;
	hb_pair_t<unsigned, hb_codepoint_t> last_range {0, 0};
	auto it = hb_iter (plan->new_to_old_gid_list);
	auto _ = *it;
	for (hb_codepoint_t gid = 0; gid < subset_num_glyphs; gid++)
	{
	hb_codepoint_t old_glyph;
	if (gid == _.first)
	{
	old_glyph = _.second;
	_ = *++it;
	}
	else
	{
	/* fonttools retains FDSelect & font dicts for missing glyphs. do the same */
	old_glyph = gid;
	}
	if (old_glyph >= last_range.second)
	last_range = src.get_fd_range (old_glyph);
	unsigned fd = last_range.first;

	if (fd != prev_fd)
	{
	set.add (fd);
	num_ranges++;
	prev_fd = fd;
	fdselect_ranges.push (code_pair_t { fd, gid });

	if (gid == old_glyph)
	gid = hb_min (_.first - 1, last_range.second - 1);
	}
	}

	subset_fd_count = set.get_population ();
	if (subset_fd_count == fdCount)
	{
	/* all font dicts belong to the subset. no need to subset FDSelect & FDArray */
	fdmap.identity (fdCount);
	}
	else
	{
	/* create a fdmap */
	fdmap.reset ();

	hb_codepoint_t fd = CFF_UNDEF_CODE;
	while (set.next (&fd))
	fdmap.add (fd);
	if (unlikely (fdmap.get_population () != subset_fd_count))
	return false;
	}

	/* update each font dict index stored as "code" in fdselect_ranges */
	for (unsigned int i = 0; i < fdselect_ranges.length; i++)
	fdselect_ranges[i].code = fdmap[fdselect_ranges[i].code];
	}

	/* determine which FDSelect format is most compact */
	if (subset_fd_count > 0xFF)
	{
	if (unlikely (src.format != 4))
	return false;
	subset_fdselect_format = 4;
	subset_fdselect_size = FDSelect::min_size + FDSelect4::min_size + FDSelect4_Range::static_size * num_ranges + HBUINT32::static_size;
	}
	else
	{
	#if CFF_SERIALIZE_FDSELECT_0
	unsigned int format0_size = FDSelect::min_size + FDSelect0::min_size + HBUINT8::static_size * subset_num_glyphs;
	#endif
	unsigned int format3_size = FDSelect::min_size + FDSelect3::min_size + FDSelect3_Range::static_size * num_ranges + HBUINT16::static_size;

	#if CFF_SERIALIZE_FDSELECT_0
	if (format0_size <= format3_size)
	{
	// subset_fdselect_format = 0;
	subset_fdselect_size = format0_size;
	}
	else
	#endif
	{
	subset_fdselect_format = 3;
	subset_fdselect_size = format3_size;
	}
	}

	return true;
	}

	template <typename FDSELECT3_4>
	static inline bool
	serialize_fdselect_3_4 (hb_serialize_context_t *c,
	const unsigned int num_glyphs,
	const FDSelect &src,
	unsigned int size,
	const hb_vector_t<code_pair_t> &fdselect_ranges)
	{
	TRACE_SERIALIZE (this);
	FDSELECT3_4 *p = c->allocate_size<FDSELECT3_4> (size);
	if (unlikely (!p)) return_trace (false);
	p->nRanges () = fdselect_ranges.length;
	for (unsigned int i = 0; i < fdselect_ranges.length; i++)
	{
	p->ranges[i].first = fdselect_ranges[i].glyph;
	p->ranges[i].fd = fdselect_ranges[i].code;
	}
	p->sentinel () = num_glyphs;
	return_trace (true);
	}

	/* Serialize a subset FDSelect format planned above. */
	bool
	hb_serialize_cff_fdselect (hb_serialize_context_t *c,
	const unsigned int num_glyphs,
	const FDSelect &src,
	unsigned int fd_count,
	unsigned int fdselect_format,
	unsigned int size,
	const hb_vector_t<code_pair_t> &fdselect_ranges)
	{
	TRACE_SERIALIZE (this);
	FDSelect *p = c->allocate_min<FDSelect> ();
	if (unlikely (!p)) return_trace (false);
	p->format = fdselect_format;
	size -= FDSelect::min_size;

	switch (fdselect_format)
	{
	#if CFF_SERIALIZE_FDSELECT_0
	case 0:
	{
	FDSelect0 *p = c->allocate_size<FDSelect0> (size);
	if (unlikely (!p)) return_trace (false);
	unsigned int range_index = 0;
	unsigned int fd = fdselect_ranges[range_index++].code;
	for (unsigned int i = 0; i < num_glyphs; i++)
	{
	if ((range_index < fdselect_ranges.len) &&
	(i >= fdselect_ranges[range_index].glyph))
	{
	fd = fdselect_ranges[range_index++].code;
	}
	p->fds[i] = fd;
	}
	return_trace (true);
	}
	#endif /* CFF_SERIALIZE_FDSELECT_0 */

	case 3:
	return serialize_fdselect_3_4<FDSelect3> (c, num_glyphs, src,
	size, fdselect_ranges);

	case 4:
	return serialize_fdselect_3_4<FDSelect4> (c, num_glyphs, src,
	size, fdselect_ranges);

	default:
	return_trace (false);
	}
	}


	#endif