harfbuzz/src/hb-ot-cbdt-table.hh

/*
 * Copyright © 2016  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): Seigo Nonaka
 */

#ifndef HB_OT_CBDT_TABLE_HH
#define HB_OT_CBDT_TABLE_HH

#include "hb-open-type-private.hh"

namespace OT {

struct SmallGlyphMetrics
{
  inline bool sanitize (hb_sanitize_context_t *c) const
  {
    TRACE_SANITIZE (this);
    return_trace (c->check_struct (this));
  }

  inline void get_extents (hb_glyph_extents_t *extents) const
  {
    extents->x_bearing = bearingX;
    extents->y_bearing = bearingY;
    extents->width = width;
    extents->height = -height;
  }

  BYTE height;
  BYTE width;
  CHAR bearingX;
  CHAR bearingY;
  BYTE advance;

  DEFINE_SIZE_STATIC(5);
};

struct SBitLineMetrics
{
  inline bool sanitize (hb_sanitize_context_t *c) const
  {
    TRACE_SANITIZE (this);
    return_trace (c->check_struct (this));
  }

  CHAR ascender;
  CHAR decender;
  BYTE widthMax;
  CHAR caretSlopeNumerator;
  CHAR caretSlopeDenominator;
  CHAR caretOffset;
  CHAR minOriginSB;
  CHAR minAdvanceSB;
  CHAR maxBeforeBL;
  CHAR minAfterBL;
  CHAR padding1;
  CHAR padding2;

  DEFINE_SIZE_STATIC(12);
};


/*
 * Index Subtables.
 */

struct IndexSubtableHeader
{
  inline bool sanitize (hb_sanitize_context_t *c) const
  {
    TRACE_SANITIZE (this);
    return_trace (c->check_struct (this));
  }

  USHORT indexFormat;
  USHORT imageFormat;
  ULONG imageDataOffset;

  DEFINE_SIZE_STATIC(8);
};

template <typename OffsetType>
struct IndexSubtableFormat1Or3
{
  inline bool sanitize (hb_sanitize_context_t *c, unsigned int glyph_count) const
  {
    TRACE_SANITIZE (this);
    return_trace (c->check_struct (this) &&
		  c->check_array (offsetArrayZ, offsetArrayZ[0].static_size, glyph_count + 1));
  }

  bool get_image_data (unsigned int idx,
		       unsigned int *offset,
		       unsigned int *length) const
  {
    if (unlikely (offsetArrayZ[idx + 1] <= offsetArrayZ[idx]))
      return false;

    *offset = header.imageDataOffset + offsetArrayZ[idx];
    *length = offsetArrayZ[idx + 1] - offsetArrayZ[idx];
    return true;
  }

  IndexSubtableHeader header;
  Offset<OffsetType> offsetArrayZ[VAR];

  DEFINE_SIZE_ARRAY(8, offsetArrayZ);
};

struct IndexSubtableFormat1 : IndexSubtableFormat1Or3<ULONG> {};
struct IndexSubtableFormat3 : IndexSubtableFormat1Or3<USHORT> {};

struct IndexSubtable
{
  inline bool sanitize (hb_sanitize_context_t *c, unsigned int glyph_count) const
  {
    TRACE_SANITIZE (this);
    if (!u.header.sanitize (c)) return_trace (false);
    switch (u.header.indexFormat) {
    case 1: return_trace (u.format1.sanitize (c, glyph_count));
    case 3: return_trace (u.format3.sanitize (c, glyph_count));
    default:return_trace (true);
    }
  }

  inline bool get_extents (hb_glyph_extents_t *extents) const
  {
    switch (u.header.indexFormat) {
    case 2: case 5: /* TODO */
    case 1: case 3: case 4: /* Variable-metrics formats do not have metrics here. */
    default:return (false);
    }
  }

  bool get_image_data (unsigned int idx,
		       unsigned int *offset,
		       unsigned int *length,
		       unsigned int *format) const
  {
    *format = u.header.imageFormat;
    switch (u.header.indexFormat) {
    case 1: return u.format1.get_image_data (idx, offset, length);
    case 3: return u.format3.get_image_data (idx, offset, length);
    default: return false;
    }
  }

  protected:
  union {
  IndexSubtableHeader	header;
  IndexSubtableFormat1	format1;
  IndexSubtableFormat3	format3;
  } u;
  public:
  DEFINE_SIZE_UNION (8, header);
};

struct IndexSubtableRecord
{
  inline bool sanitize (hb_sanitize_context_t *c, const void *base) const
  {
    TRACE_SANITIZE (this);
    return_trace (c->check_struct (this) &&
		  firstGlyphIndex <= lastGlyphIndex &&
		  offsetToSubtable.sanitize (c, this, lastGlyphIndex - firstGlyphIndex + 1));
  }

  inline bool get_extents (hb_glyph_extents_t *extents) const
  {
    return (this+offsetToSubtable).get_extents (extents);
  }

  bool get_image_data (unsigned int gid,
		       unsigned int *offset,
		       unsigned int *length,
		       unsigned int *format) const
  {
    if (gid < firstGlyphIndex || gid > lastGlyphIndex)
    {
      return false;
    }
    return (this+offsetToSubtable).get_image_data (gid - firstGlyphIndex,
						   offset, length, format);
  }

  USHORT firstGlyphIndex;
  USHORT lastGlyphIndex;
  OffsetTo<IndexSubtable, ULONG> offsetToSubtable;

  DEFINE_SIZE_STATIC(8);
};

struct IndexSubtableArray
{
  inline bool sanitize (hb_sanitize_context_t *c, unsigned int count) const
  {
    TRACE_SANITIZE (this);
    if (unlikely (!c->check_array (&indexSubtablesZ, indexSubtablesZ[0].static_size, sizeof (count))))
      return_trace (false);
    for (unsigned int i = 0; i < count; i++)
      if (unlikely (!indexSubtablesZ[i].sanitize (c, this)))
	return_trace (false);
    return_trace (true);
  }

  public:
  const IndexSubtableRecord* find_table (hb_codepoint_t glyph, unsigned int numTables) const
  {
    for (unsigned int i = 0; i < numTables; ++i)
    {
      unsigned int firstGlyphIndex = indexSubtablesZ[i].firstGlyphIndex;
      unsigned int lastGlyphIndex = indexSubtablesZ[i].lastGlyphIndex;
      if (firstGlyphIndex <= glyph && glyph <= lastGlyphIndex) {
        return &indexSubtablesZ[i];
      }
    }
    return NULL;
  }

  protected:
  IndexSubtableRecord indexSubtablesZ[VAR];

  public:
  DEFINE_SIZE_ARRAY(0, indexSubtablesZ);
};

struct BitmapSizeTable
{
  friend struct CBLC;

  inline bool sanitize (hb_sanitize_context_t *c, const void *base) const
  {
    TRACE_SANITIZE (this);
    return_trace (c->check_struct (this) &&
		  indexSubtableArrayOffset.sanitize (c, base, numberOfIndexSubtables) &&
		  c->check_range (&(base+indexSubtableArrayOffset), indexTablesSize) &&
		  horizontal.sanitize (c) &&
		  vertical.sanitize (c));
  }

  const IndexSubtableRecord *find_table (hb_codepoint_t glyph, const void *base) const
  {
    return (base+indexSubtableArrayOffset).find_table (glyph, numberOfIndexSubtables);
  }

  protected:
  OffsetTo<IndexSubtableArray, ULONG> indexSubtableArrayOffset;
  ULONG indexTablesSize;
  ULONG numberOfIndexSubtables;
  ULONG colorRef;
  SBitLineMetrics horizontal;
  SBitLineMetrics vertical;
  USHORT startGlyphIndex;
  USHORT endGlyphIndex;
  BYTE ppemX;
  BYTE ppemY;
  BYTE bitDepth;
  CHAR flags;

public:
  DEFINE_SIZE_STATIC(48);
};


/*
 * Glyph Bitmap Data Formats.
 */

struct GlyphBitmapDataFormat17
{
  SmallGlyphMetrics glyphMetrics;
  ULONG dataLen;
  BYTE dataZ[VAR];

  DEFINE_SIZE_ARRAY(9, dataZ);
};


/*
 * CBLC -- Color Bitmap Location Table
 */

#define HB_OT_TAG_CBLC HB_TAG('C','B','L','C')

struct CBLC
{
  static const hb_tag_t tableTag = HB_OT_TAG_CBLC;

  inline bool sanitize (hb_sanitize_context_t *c) const
  {
    TRACE_SANITIZE (this);
    return_trace (c->check_struct (this) &&
		  likely (version.major == 2 || version.major == 3) &&
		  sizeTables.sanitize (c, this));
  }

  public:
  const IndexSubtableRecord *find_table (hb_codepoint_t glyph,
					 unsigned int *x_ppem, unsigned int *y_ppem) const
  {
    /* TODO: Make it possible to select strike. */

    const BitmapSizeTable *sizeTable = &Null(BitmapSizeTable);
    unsigned int count = sizeTables.len;
    for (uint32_t i = 0; i < count; ++i)
    {
      unsigned int startGlyphIndex = sizeTables.array[i].startGlyphIndex;
      unsigned int endGlyphIndex = sizeTables.array[i].endGlyphIndex;
      if (startGlyphIndex <= glyph && glyph <= endGlyphIndex)
      {
	sizeTable = &sizeTables[i];
	break;
      }
    }

    *x_ppem = sizeTable->ppemX;
    *y_ppem = sizeTable->ppemY;

    return sizeTable->find_table (glyph, this);
  }

  protected:
  FixedVersion<>version;
  ArrayOf<BitmapSizeTable, ULONG> sizeTables;

  public:
  DEFINE_SIZE_ARRAY(8, sizeTables);
};

/*
 * CBDT -- Color Bitmap Data Table
 */
#define HB_OT_TAG_CBDT HB_TAG('C','B','D','T')

struct CBDT
{
  static const hb_tag_t tableTag = HB_OT_TAG_CBDT;

  inline bool sanitize (hb_sanitize_context_t *c) const
  {
    TRACE_SANITIZE (this);
    return_trace (c->check_struct (this) &&
		  likely (version.major == 2 || version.major == 3));
  }

  protected:
  FixedVersion<>version;
  BYTE dataZ[VAR];

  public:
  DEFINE_SIZE_ARRAY(4, dataZ);
};

} /* namespace OT */

#endif /* HB_OT_CBDT_TABLE_HH */