kc3-lang/harfbuzz/src/hb-ot-color-svg-table.hh

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• Hash : 10642b3f
  Author :
  Date : 2018-09-15T19:43:33
  

  Disallow null-enabled offsets to unsized structures...
  
  ...like UnsizedArrayOf<>.
  
  This fixes a class of crasher bugs, mostly with color and AAT tables.  We
  cannot use nullable offsets to varsized data that does not declare min_size,
  because it's nost safe to use our fixed-size null pool for types that have
  their size external.  So, use non_null'able offsets for these.
  
  A further enhancement would be to make use of min_size in Null<> itself.
  Will try that after.
  

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• src/hb-ot-color-svg-table.hh

• /*
   * Copyright © 2018  Ebrahim Byagowi
   *
   *  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_COLOR_SVG_TABLE_HH
  #define HB_OT_COLOR_SVG_TABLE_HH
  
  #include "hb-open-type.hh"
  
  /*
   * SVG -- SVG (Scalable Vector Graphics)
   * https://docs.microsoft.com/en-us/typography/opentype/spec/svg
   */
  
  #define HB_OT_TAG_SVG HB_TAG('S','V','G',' ')
  
  
  namespace OT {
  
  
  struct SVGDocumentIndexEntry
  {
    friend struct SVG;
  
    inline bool sanitize (hb_sanitize_context_t *c, const void* base) const
    {
      TRACE_SANITIZE (this);
      return_trace (c->check_struct (this) &&
  		  (base+svgDoc).sanitize (c, svgDocLength));
    }
  
    protected:
    HBUINT16	startGlyphID;	/* The first glyph ID in the range described by
  				 * this index entry. */
    HBUINT16	endGlyphID;	/* The last glyph ID in the range described by
  				 * this index entry. Must be >= startGlyphID. */
    LOffsetTo<UnsizedArrayOf<HBUINT8>, false>
  		svgDoc;		/* Offset from the beginning of the SVG Document Index
  				 * to an SVG document. Must be non-zero. */
    HBUINT32 svgDocLength;	/* Length of the SVG document.
  				 * Must be non-zero. */
    public:
    DEFINE_SIZE_STATIC (12);
  };
  
  struct SVGDocumentIndex
  {
    friend struct SVG;
  
    inline bool sanitize (hb_sanitize_context_t *c) const
    {
      TRACE_SANITIZE (this);
      return_trace (c->check_struct (this) &&
  		  entries.sanitize (c, this));
    }
  
    protected:
    ArrayOf<SVGDocumentIndexEntry>
  		entries;	/* Array of SVG Document Index Entries. */
    public:
    DEFINE_SIZE_ARRAY (2, entries);
  };
  
  struct SVG
  {
    static const hb_tag_t tableTag = HB_OT_TAG_SVG;
  
    inline bool sanitize (hb_sanitize_context_t *c) const
    {
      TRACE_SANITIZE (this);
      return_trace (likely (c->check_struct (this) &&
  			  (this+svgDocIndex).sanitize (c)));
    }
  
    struct accelerator_t
    {
      inline void init (hb_face_t *face)
      {
        svg_blob = hb_sanitize_context_t().reference_table<SVG> (face);
        svg_len = hb_blob_get_length (svg_blob);
        svg = svg_blob->as<SVG> ();
      }
  
      inline void fini (void)
      {
        hb_blob_destroy (svg_blob);
      }
  
      inline void
      dump (void (*callback) (const uint8_t* data, unsigned int length,
  			    unsigned int start_glyph, unsigned int end_glyph)) const
      {
        const SVGDocumentIndex &index = svg+svg->svgDocIndex;
        const ArrayOf<SVGDocumentIndexEntry> &entries = index.entries;
        for (unsigned int i = 0; i < entries.len; ++i)
        {
  	const SVGDocumentIndexEntry &entry = entries[i];
  	callback ((const uint8_t*) &entry.svgDoc (&index), entry.svgDocLength,
  						  entry.startGlyphID, entry.endGlyphID);
        }
      }
  
      private:
      hb_blob_t *svg_blob;
      const SVG *svg;
  
      unsigned int svg_len;
    };
  
    protected:
    HBUINT16	version;	/* Table version (starting at 0). */
    LOffsetTo<SVGDocumentIndex>
  		svgDocIndex;	/* Offset (relative to the start of the SVG table) to the
  				 * SVG Documents Index. Must be non-zero. */
    HBUINT32	reserved;	/* Set to 0. */
    public:
    DEFINE_SIZE_STATIC (10);
  };
  
  } /* namespace OT */
  
  
  #endif /* HB_OT_COLOR_SVG_TABLE_HH */
  

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