kc3-lang/harfbuzz/src/hb-ot-head-private.hh

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• Hash : ac0c1663
  Author :
  Date : 2010-10-01T19:09:23
  

  Avoid div-by-zero, validate upem
  

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• src/hb-ot-head-private.hh

• /*
   * Copyright (C) 2010  Red Hat, 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.
   *
   * Red Hat Author(s): Behdad Esfahbod
   */
  
  #ifndef HB_OT_HEAD_PRIVATE_HH
  #define HB_OT_HEAD_PRIVATE_HH
  
  #include "hb-open-type-private.hh"
  
  HB_BEGIN_DECLS
  
  
  /*
   * head
   */
  
  #define HB_OT_TAG_head HB_TAG('h','e','a','d')
  
  struct head
  {
    static const hb_tag_t Tag	= HB_OT_TAG_head;
  
    inline unsigned int get_upem (void) const {
      unsigned int upem = unitsPerEm;
      /* If no valid head table found, assume 1000, which matches typicaly Type1 usage. */
      return 16 <= upem && upem <= 16384 ? upem : 1000;
    }
  
    inline bool sanitize (hb_sanitize_context_t *c) {
      TRACE_SANITIZE ();
      /* Shall we check for magicNumber here?  Who cares? */
      return c->check_struct (this) && likely (version.major == 1);
    }
  
    private:
    FixedVersion	version;		/* Version of the head table--currently
  					 * 0x00010000 for version 1.0. */
    FixedVersion	fontRevision;		/* Set by font manufacturer. */
    ULONG		checkSumAdjustment;	/* To compute: set it to 0, sum the
  					 * entire font as ULONG, then store
  					 * 0xB1B0AFBA - sum. */
    ULONG		magicNumber;		/* Set to 0x5F0F3CF5. */
    USHORT	flags;			/* Bit 0: Baseline for font at y=0;
  					 * Bit 1: Left sidebearing point at x=0;
  					 * Bit 2: Instructions may depend on point size;
  					 * Bit 3: Force ppem to integer values for all
  					 *   internal scaler math; may use fractional
  					 *   ppem sizes if this bit is clear;
  					 * Bit 4: Instructions may alter advance width
  					 *   (the advance widths might not scale linearly);
  
  					 * Bits 5-10: These should be set according to
  					 *   Apple's specification. However, they are not
  					 *   implemented in OpenType.
  					 * Bit 5: This bit should be set in fonts that are
  					 *   intended to e laid out vertically, and in
  					 *   which the glyphs have been drawn such that an
  					 *   x-coordinate of 0 corresponds to the desired
  					 *   vertical baseline.
  					 * Bit 6: This bit must be set to zero.
  					 * Bit 7: This bit should be set if the font
  					 *   requires layout for correct linguistic
  					 *   rendering (e.g. Arabic fonts).
  					 * Bit 8: This bit should be set for a GX font
  					 *   which has one or more metamorphosis effects
  					 *   designated as happening by default.
  					 * Bit 9: This bit should be set if the font
  					 *   contains any strong right-to-left glyphs.
  					 * Bit 10: This bit should be set if the font
  					 *   contains Indic-style rearrangement effects.
  
  					 * Bit 11: Font data is 'lossless,' as a result
  					 *   of having been compressed and decompressed
  					 *   with the Agfa MicroType Express engine.
  					 * Bit 12: Font converted (produce compatible metrics)
  					 * Bit 13: Font optimized for ClearType™.
  					 *   Note, fonts that rely on embedded bitmaps (EBDT)
  					 *   for rendering should not be considered optimized
  					 *   for ClearType, and therefore should keep this bit
  					 *   cleared.
  					 * Bit 14: Reserved, set to 0
  					 * Bit 15: Reserved, set to 0. */
    USHORT	unitsPerEm;		/* Valid range is from 16 to 16384. This value
  					 * should be a power of 2 for fonts that have
  					 * TrueType outlines. */
    LONGDATETIME	created;		/* Number of seconds since 12:00 midnight,
  					   January 1, 1904. 64-bit integer */
    LONGDATETIME	modified;		/* Number of seconds since 12:00 midnight,
  					   January 1, 1904. 64-bit integer */
    SHORT		xMin;			/* For all glyph bounding boxes. */
    SHORT		yMin;			/* For all glyph bounding boxes. */
    SHORT		xMax;			/* For all glyph bounding boxes. */
    SHORT		yMax;			/* For all glyph bounding boxes. */
    USHORT	macStyle;		/* Bit 0: Bold (if set to 1);
  					 * Bit 1: Italic (if set to 1)
  					 * Bit 2: Underline (if set to 1)
  					 * Bit 3: Outline (if set to 1)
  					 * Bit 4: Shadow (if set to 1)
  					 * Bit 5: Condensed (if set to 1)
  					 * Bit 6: Extended (if set to 1)
  					 * Bits 7-15: Reserved (set to 0). */
    USHORT	lowestRecPPEM;		/* Smallest readable size in pixels. */
    SHORT		fontDirectionHint;	/* Deprecated (Set to 2).
  					 * 0: Fully mixed directional glyphs;
  					 * 1: Only strongly left to right;
  					 * 2: Like 1 but also contains neutrals;
  					 * -1: Only strongly right to left;
  					 * -2: Like -1 but also contains neutrals. */
    SHORT		indexToLocFormat;	/* 0 for short offsets, 1 for long. */
    SHORT		glyphDataFormat;	/* 0 for current format. */
    public:
    DEFINE_SIZE_STATIC (54);
  };
  
  
  HB_END_DECLS
  
  #endif /* HB_OT_HEAD_PRIVATE_HH */
  

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