src/hb-ot-hmtx-table.hh - third_party/harfbuzz - Git at Google

 /*
  * Copyright © 2011,2012  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, Roderick Sheeter
  */

 #ifndef HB_OT_HMTX_TABLE_HH
 #define HB_OT_HMTX_TABLE_HH

 #include "hb-open-type-private.hh"
 #include "hb-ot-hhea-table.hh"
 #include "hb-ot-os2-table.hh"
 #include "hb-ot-var-hvar-table.hh"


 namespace OT {


 /*
  * hmtx -- The Horizontal Metrics Table
  * vmtx -- The Vertical Metrics Table
  */

 #define HB_OT_TAG_hmtx HB_TAG('h','m','t','x')
 #define HB_OT_TAG_vmtx HB_TAG('v','m','t','x')


 struct LongMetric
 {
   UFWORD	advance; /* Advance width/height. */
   FWORD		lsb; /* Leading (left/top) side bearing. */
   public:
   DEFINE_SIZE_STATIC (4);
 };

 template <typename T, typename H>
 struct hmtxvmtx
 {
   inline bool sanitize (hb_sanitize_context_t *c) const
   {
     TRACE_SANITIZE (this);
     /* We don't check for anything specific here.  The users of the
      * struct do all the hard work... */
     return_trace (true);
   }


   inline bool subset_update_header (hb_subset_plan_t *plan,
                                     unsigned int num_hmetrics) const
   {
     hb_blob_t *src_blob = OT::Sanitizer<H> ().sanitize (plan->source->reference_table (H::tableTag));
     hb_blob_t *dest_blob = hb_blob_copy_writable_or_fail(src_blob);
     hb_blob_destroy (src_blob);

     if (unlikely (!dest_blob)) {
       return false;
     }

     unsigned int length;
     H *table = (H *) hb_blob_get_data (dest_blob, &length);
     table->numberOfLongMetrics.set (num_hmetrics);

     bool result = hb_subset_plan_add_table (plan, H::tableTag, dest_blob);
     hb_blob_destroy (dest_blob);

     return result;
   }

   inline bool subset (hb_subset_plan_t *plan) const
   {
     typename T::accelerator_t _mtx;
     _mtx.init (plan->source);

     /* All the trailing glyphs with the same advance can use one LongMetric
      * and just keep LSB */
     hb_prealloced_array_t<hb_codepoint_t> &gids = plan->gids_to_retain_sorted;
     unsigned int num_advances = gids.len;
     unsigned int last_advance = _mtx.get_advance (gids[num_advances - 1]);
     while (num_advances > 1
         && last_advance == _mtx.get_advance (gids[num_advances - 2]))
     {
       num_advances--;
     }

     /* alloc the new table */
     size_t dest_sz = num_advances * 4
                   + (gids.len - num_advances) * 2;
     void *dest = (void *) malloc (dest_sz);
     if (unlikely (!dest))
     {
       return false;
     }
     DEBUG_MSG(SUBSET, nullptr, "%c%c%c%c in src has %d advances, %d lsbs", HB_UNTAG(T::tableTag), _mtx.num_advances, _mtx.num_metrics - _mtx.num_advances);
     DEBUG_MSG(SUBSET, nullptr, "%c%c%c%c in dest has %d advances, %d lsbs, %u bytes", HB_UNTAG(T::tableTag), num_advances, gids.len - num_advances, (unsigned int) dest_sz);

     const char *source_table = hb_blob_get_data (_mtx.blob, nullptr);
     // Copy everything over
     LongMetric * old_metrics = (LongMetric *) source_table;
     FWORD *lsbs = (FWORD *) (old_metrics + _mtx.num_advances);
     char * dest_pos = (char *) dest;
     for (unsigned int i = 0; i < gids.len; i++)
     {
       /* the last metric or the one for gids[i] */
       LongMetric *src_metric = old_metrics + MIN ((hb_codepoint_t) _mtx.num_advances - 1, gids[i]);
       if (gids[i] < _mtx.num_advances)
       {
         /* src is a LongMetric */
         if (i < num_advances)
         {
           /* dest is a LongMetric, copy it */
           *((LongMetric *) dest_pos) = *src_metric;
         }
         else
         {
           /* dest just lsb */
           *((FWORD *) dest_pos) = src_metric->lsb;
         }
       }
       else
       {
         FWORD src_lsb = *(lsbs + gids[i] - _mtx.num_advances);
         if (i < num_advances)
         {
           /* dest needs a full LongMetric */
           LongMetric *metric = (LongMetric *)dest_pos;
           metric->advance = src_metric->advance;
           metric->lsb = src_lsb;
         }
         else
         {
           /* dest just needs an lsb */
           *((FWORD *) dest_pos) = src_lsb;
         }
       }
       dest_pos += (i < num_advances ? 4 : 2);
     }
     _mtx.fini ();

     // Amend header num hmetrics
     if (unlikely (!subset_update_header (plan, num_advances)))
     {
       free (dest);
       return false;
     }

     hb_blob_t *result = hb_blob_create ((const char *)dest,
                                         dest_sz,
                                         HB_MEMORY_MODE_READONLY,
                                         dest,
                                         free);
     bool success = hb_subset_plan_add_table (plan, T::tableTag, result);
     hb_blob_destroy (result);
     return success;
   }

   struct accelerator_t
   {
     friend struct hmtxvmtx;

     inline void init (hb_face_t *face,
 		      unsigned int default_advance_ = 0)
     {
       default_advance = default_advance_ ? default_advance_ : hb_face_get_upem (face);

       bool got_font_extents = false;
       if (T::os2Tag)
       {
 	hb_blob_t *os2_blob = Sanitizer<os2> ().sanitize (face->reference_table (T::os2Tag));
 	const os2 *os2_table = Sanitizer<os2>::lock_instance (os2_blob);
 #define USE_TYPO_METRICS (1u<<7)
 	if (0 != (os2_table->fsSelection & USE_TYPO_METRICS))
 	{
 	  ascender = os2_table->sTypoAscender;
 	  descender = os2_table->sTypoDescender;
 	  line_gap = os2_table->sTypoLineGap;
 	  got_font_extents = (ascender | descender) != 0;
 	}
 	hb_blob_destroy (os2_blob);
       }

       hb_blob_t *_hea_blob = Sanitizer<H> ().sanitize (face->reference_table (H::tableTag));
       const H *_hea_table = Sanitizer<H>::lock_instance (_hea_blob);
       num_advances = _hea_table->numberOfLongMetrics;
       if (!got_font_extents)
       {
 	ascender = _hea_table->ascender;
 	descender = _hea_table->descender;
 	line_gap = _hea_table->lineGap;
 	got_font_extents = (ascender | descender) != 0;
       }
       hb_blob_destroy (_hea_blob);

       has_font_extents = got_font_extents;

       blob = Sanitizer<hmtxvmtx> ().sanitize (face->reference_table (T::tableTag));

       /* Cap num_metrics() and num_advances() based on table length. */
       unsigned int len = hb_blob_get_length (blob);
       if (unlikely (num_advances * 4 > len))
 	num_advances = len / 4;
       num_metrics = num_advances + (len - 4 * num_advances) / 2;

       /* We MUST set num_metrics to zero if num_advances is zero.
        * Our get_advance() depends on that. */
       if (unlikely (!num_advances))
       {
 	num_metrics = num_advances = 0;
 	hb_blob_destroy (blob);
 	blob = hb_blob_get_empty ();
       }
       table = Sanitizer<hmtxvmtx>::lock_instance (blob);

       var_blob = Sanitizer<HVARVVAR> ().sanitize (face->reference_table (T::variationsTag));
       var_table = Sanitizer<HVARVVAR>::lock_instance (var_blob);
     }

     inline void fini (void)
     {
       hb_blob_destroy (blob);
       hb_blob_destroy (var_blob);
     }

     inline unsigned int get_advance (hb_codepoint_t  glyph) const
     {
       if (unlikely (glyph >= num_metrics))
       {
         /* If num_metrics is zero, it means we don't have the metrics table
          * for this direction: return default advance.  Otherwise, it means that the
          * glyph index is out of bound: return zero. */
         if (num_metrics)
           return 0;
         else
           return default_advance;
       }

       return table->longMetric[MIN (glyph, (uint32_t) num_advances - 1)].advance;
     }

     inline unsigned int get_advance (hb_codepoint_t  glyph,
                                      hb_font_t      *font) const
     {
       unsigned int advance = get_advance (glyph);
       if (likely(glyph < num_metrics))
       {
         advance += (font->num_coords ? var_table->get_advance_var (glyph, font->coords, font->num_coords) : 0); // TODO Optimize?!
       }
       return advance;
     }

     public:
     bool has_font_extents;
     unsigned short ascender;
     unsigned short descender;
     unsigned short line_gap;

     protected:
     unsigned int num_metrics;
     unsigned int num_advances;
     unsigned int default_advance;

     private:
     const hmtxvmtx *table;
     hb_blob_t *blob;
     const HVARVVAR *var_table;
     hb_blob_t *var_blob;
   };

   protected:
   LongMetric	longMetric[VAR];	/* Paired advance width and leading
 					 * bearing values for each glyph. The
 					 * value numOfHMetrics comes from
 					 * the 'hhea' table. If the font is
 					 * monospaced, only one entry need
 					 * be in the array, but that entry is
 					 * required. The last entry applies to
 					 * all subsequent glyphs. */
 /*FWORD		leadingBearingX[VAR];*/	/* Here the advance is assumed
 					 * to be the same as the advance
 					 * for the last entry above. The
 					 * number of entries in this array is
 					 * derived from numGlyphs (from 'maxp'
 					 * table) minus numberOfLongMetrics.
 					 * This generally is used with a run
 					 * of monospaced glyphs (e.g., Kanji
 					 * fonts or Courier fonts). Only one
 					 * run is allowed and it must be at
 					 * the end. This allows a monospaced
 					 * font to vary the side bearing
 					 * values for each glyph. */
   public:
   DEFINE_SIZE_ARRAY (0, longMetric);
 };

 struct hmtx : hmtxvmtx<hmtx, hhea> {
   static const hb_tag_t tableTag	= HB_OT_TAG_hmtx;
   static const hb_tag_t variationsTag	= HB_OT_TAG_HVAR;
   static const hb_tag_t os2Tag		= HB_OT_TAG_os2;
 };
 struct vmtx : hmtxvmtx<vmtx, vhea> {
   static const hb_tag_t tableTag	= HB_OT_TAG_vmtx;
   static const hb_tag_t variationsTag	= HB_OT_TAG_VVAR;
   static const hb_tag_t os2Tag		= HB_TAG_NONE;
 };

 } /* namespace OT */


 #endif /* HB_OT_HMTX_TABLE_HH */
	/*
	* Copyright © 2011,2012 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, Roderick Sheeter
	*/

	#ifndef HB_OT_HMTX_TABLE_HH
	#define HB_OT_HMTX_TABLE_HH

	#include "hb-open-type-private.hh"
	#include "hb-ot-hhea-table.hh"
	#include "hb-ot-os2-table.hh"
	#include "hb-ot-var-hvar-table.hh"


	namespace OT {


	/*
	* hmtx -- The Horizontal Metrics Table
	* vmtx -- The Vertical Metrics Table
	*/

	#define HB_OT_TAG_hmtx HB_TAG('h','m','t','x')
	#define HB_OT_TAG_vmtx HB_TAG('v','m','t','x')


	struct LongMetric
	{
	UFWORD advance; /* Advance width/height. */
	FWORD lsb; /* Leading (left/top) side bearing. */
	public:
	DEFINE_SIZE_STATIC (4);
	};

	template <typename T, typename H>
	struct hmtxvmtx
	{
	inline bool sanitize (hb_sanitize_context_t *c) const
	{
	TRACE_SANITIZE (this);
	/* We don't check for anything specific here. The users of the
	* struct do all the hard work... */
	return_trace (true);
	}


	inline bool subset_update_header (hb_subset_plan_t *plan,
	unsigned int num_hmetrics) const
	{
	hb_blob_t *src_blob = OT::Sanitizer<H> ().sanitize (plan->source->reference_table (H::tableTag));
	hb_blob_t *dest_blob = hb_blob_copy_writable_or_fail(src_blob);
	hb_blob_destroy (src_blob);

	if (unlikely (!dest_blob)) {
	return false;
	}

	unsigned int length;
	H table = (H ) hb_blob_get_data (dest_blob, &length);
	table->numberOfLongMetrics.set (num_hmetrics);

	bool result = hb_subset_plan_add_table (plan, H::tableTag, dest_blob);
	hb_blob_destroy (dest_blob);

	return result;
	}

	inline bool subset (hb_subset_plan_t *plan) const
	{
	typename T::accelerator_t _mtx;
	_mtx.init (plan->source);

	/* All the trailing glyphs with the same advance can use one LongMetric
	* and just keep LSB */
	hb_prealloced_array_t<hb_codepoint_t> &gids = plan->gids_to_retain_sorted;
	unsigned int num_advances = gids.len;
	unsigned int last_advance = _mtx.get_advance (gids[num_advances - 1]);
	while (num_advances > 1
	&& last_advance == _mtx.get_advance (gids[num_advances - 2]))
	{
	num_advances--;
	}

	/* alloc the new table */
	size_t dest_sz = num_advances * 4
	+ (gids.len - num_advances) * 2;
	void dest = (void ) malloc (dest_sz);
	if (unlikely (!dest))
	{
	return false;
	}
	DEBUG_MSG(SUBSET, nullptr, "%c%c%c%c in src has %d advances, %d lsbs", HB_UNTAG(T::tableTag), _mtx.num_advances, _mtx.num_metrics - _mtx.num_advances);
	DEBUG_MSG(SUBSET, nullptr, "%c%c%c%c in dest has %d advances, %d lsbs, %u bytes", HB_UNTAG(T::tableTag), num_advances, gids.len - num_advances, (unsigned int) dest_sz);

	const char *source_table = hb_blob_get_data (_mtx.blob, nullptr);
	// Copy everything over
	LongMetric * old_metrics = (LongMetric *) source_table;
	FWORD lsbs = (FWORD ) (old_metrics + _mtx.num_advances);
	char * dest_pos = (char *) dest;
	for (unsigned int i = 0; i < gids.len; i++)
	{
	/* the last metric or the one for gids[i] */
	LongMetric *src_metric = old_metrics + MIN ((hb_codepoint_t) _mtx.num_advances - 1, gids[i]);
	if (gids[i] < _mtx.num_advances)
	{
	/* src is a LongMetric */
	if (i < num_advances)
	{
	/* dest is a LongMetric, copy it */
	((LongMetric ) dest_pos) = *src_metric;
	}
	else
	{
	/* dest just lsb */
	((FWORD ) dest_pos) = src_metric->lsb;
	}
	}
	else
	{
	FWORD src_lsb = *(lsbs + gids[i] - _mtx.num_advances);
	if (i < num_advances)
	{
	/* dest needs a full LongMetric */
	LongMetric metric = (LongMetric )dest_pos;
	metric->advance = src_metric->advance;
	metric->lsb = src_lsb;
	}
	else
	{
	/* dest just needs an lsb */
	((FWORD ) dest_pos) = src_lsb;
	}
	}
	dest_pos += (i < num_advances ? 4 : 2);
	}
	_mtx.fini ();

	// Amend header num hmetrics
	if (unlikely (!subset_update_header (plan, num_advances)))
	{
	free (dest);
	return false;
	}

	hb_blob_t result = hb_blob_create ((const char )dest,
	dest_sz,
	HB_MEMORY_MODE_READONLY,
	dest,
	free);
	bool success = hb_subset_plan_add_table (plan, T::tableTag, result);
	hb_blob_destroy (result);
	return success;
	}

	struct accelerator_t
	{
	friend struct hmtxvmtx;

	inline void init (hb_face_t *face,
	unsigned int default_advance_ = 0)
	{
	default_advance = default_advance_ ? default_advance_ : hb_face_get_upem (face);

	bool got_font_extents = false;
	if (T::os2Tag)
	{
	hb_blob_t *os2_blob = Sanitizer<os2> ().sanitize (face->reference_table (T::os2Tag));
	const os2 *os2_table = Sanitizer<os2>::lock_instance (os2_blob);
	#define USE_TYPO_METRICS (1u<<7)
	if (0 != (os2_table->fsSelection & USE_TYPO_METRICS))
	{
	ascender = os2_table->sTypoAscender;
	descender = os2_table->sTypoDescender;
	line_gap = os2_table->sTypoLineGap;
	got_font_extents = (ascender \| descender) != 0;
	}
	hb_blob_destroy (os2_blob);
	}

	hb_blob_t *_hea_blob = Sanitizer<H> ().sanitize (face->reference_table (H::tableTag));
	const H *_hea_table = Sanitizer<H>::lock_instance (_hea_blob);
	num_advances = _hea_table->numberOfLongMetrics;
	if (!got_font_extents)
	{
	ascender = _hea_table->ascender;
	descender = _hea_table->descender;
	line_gap = _hea_table->lineGap;
	got_font_extents = (ascender \| descender) != 0;
	}
	hb_blob_destroy (_hea_blob);

	has_font_extents = got_font_extents;

	blob = Sanitizer<hmtxvmtx> ().sanitize (face->reference_table (T::tableTag));

	/* Cap num_metrics() and num_advances() based on table length. */
	unsigned int len = hb_blob_get_length (blob);
	if (unlikely (num_advances * 4 > len))
	num_advances = len / 4;
	num_metrics = num_advances + (len - 4 * num_advances) / 2;

	/* We MUST set num_metrics to zero if num_advances is zero.
	* Our get_advance() depends on that. */
	if (unlikely (!num_advances))
	{
	num_metrics = num_advances = 0;
	hb_blob_destroy (blob);
	blob = hb_blob_get_empty ();
	}
	table = Sanitizer<hmtxvmtx>::lock_instance (blob);

	var_blob = Sanitizer<HVARVVAR> ().sanitize (face->reference_table (T::variationsTag));
	var_table = Sanitizer<HVARVVAR>::lock_instance (var_blob);
	}

	inline void fini (void)
	{
	hb_blob_destroy (blob);
	hb_blob_destroy (var_blob);
	}

	inline unsigned int get_advance (hb_codepoint_t glyph) const
	{
	if (unlikely (glyph >= num_metrics))
	{
	/* If num_metrics is zero, it means we don't have the metrics table
	* for this direction: return default advance. Otherwise, it means that the
	* glyph index is out of bound: return zero. */
	if (num_metrics)
	return 0;
	else
	return default_advance;
	}

	return table->longMetric[MIN (glyph, (uint32_t) num_advances - 1)].advance;
	}

	inline unsigned int get_advance (hb_codepoint_t glyph,
	hb_font_t *font) const
	{
	unsigned int advance = get_advance (glyph);
	if (likely(glyph < num_metrics))
	{
	advance += (font->num_coords ? var_table->get_advance_var (glyph, font->coords, font->num_coords) : 0); // TODO Optimize?!
	}
	return advance;
	}

	public:
	bool has_font_extents;
	unsigned short ascender;
	unsigned short descender;
	unsigned short line_gap;

	protected:
	unsigned int num_metrics;
	unsigned int num_advances;
	unsigned int default_advance;

	private:
	const hmtxvmtx *table;
	hb_blob_t *blob;
	const HVARVVAR *var_table;
	hb_blob_t *var_blob;
	};

	protected:
	LongMetric longMetric[VAR]; /* Paired advance width and leading
	* bearing values for each glyph. The
	* value numOfHMetrics comes from
	* the 'hhea' table. If the font is
	* monospaced, only one entry need
	* be in the array, but that entry is
	* required. The last entry applies to
	* all subsequent glyphs. */
	/FWORD leadingBearingX[VAR];/ /* Here the advance is assumed
	* to be the same as the advance
	* for the last entry above. The
	* number of entries in this array is
	* derived from numGlyphs (from 'maxp'
	* table) minus numberOfLongMetrics.
	* This generally is used with a run
	* of monospaced glyphs (e.g., Kanji
	* fonts or Courier fonts). Only one
	* run is allowed and it must be at
	* the end. This allows a monospaced
	* font to vary the side bearing
	* values for each glyph. */
	public:
	DEFINE_SIZE_ARRAY (0, longMetric);
	};

	struct hmtx : hmtxvmtx<hmtx, hhea> {
	static const hb_tag_t tableTag = HB_OT_TAG_hmtx;
	static const hb_tag_t variationsTag = HB_OT_TAG_HVAR;
	static const hb_tag_t os2Tag = HB_OT_TAG_os2;
	};
	struct vmtx : hmtxvmtx<vmtx, vhea> {
	static const hb_tag_t tableTag = HB_OT_TAG_vmtx;
	static const hb_tag_t variationsTag = HB_OT_TAG_VVAR;
	static const hb_tag_t os2Tag = HB_TAG_NONE;
	};

	} /* namespace OT */


	#endif /* HB_OT_HMTX_TABLE_HH */