DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Header

Mercurial (239374682969)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158
// Copyright (c) 2018 The OTS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "gvar.h"

#include "fvar.h"
#include "maxp.h"
#include "variations.h"

#define TABLE_NAME "gvar"

namespace ots {

// -----------------------------------------------------------------------------
// OpenTypeGVAR
// -----------------------------------------------------------------------------

static bool ParseSharedTuples(const Font* font, const uint8_t* data, size_t length,
                              size_t sharedTupleCount, size_t axisCount) {
  Buffer subtable(data, length);
  for (unsigned i = 0; i < sharedTupleCount; i++) {
    for (unsigned j = 0; j < axisCount; j++) {
      int16_t coordinate;
      if (!subtable.ReadS16(&coordinate)) {
        return OTS_FAILURE_MSG("Failed to read shared tuple coordinate");
      }
    }
  }
  return true;
}

static bool ParseGlyphVariationDataArray(const Font* font, const uint8_t* data, size_t length,
                                         uint16_t flags, size_t glyphCount, size_t axisCount,
                                         size_t sharedTupleCount,
                                         const uint8_t* glyphVariationData,
                                         size_t glyphVariationDataLength) {
  Buffer subtable(data, length);

  bool glyphVariationDataOffsetsAreLong = (flags & 0x0001u);
  uint32_t prevOffset = 0;
  for (size_t i = 0; i < glyphCount + 1; i++) {
    uint32_t offset;
    if (glyphVariationDataOffsetsAreLong) {
      if (!subtable.ReadU32(&offset)) {
        return OTS_FAILURE_MSG("Failed to read GlyphVariationData offset");
      }
    } else {
      uint16_t halfOffset;
      if (!subtable.ReadU16(&halfOffset)) {
        return OTS_FAILURE_MSG("Failed to read GlyphVariationData offset");
      }
      offset = halfOffset * 2;
    }

    if (i > 0 && offset > prevOffset) {
      if (prevOffset > glyphVariationDataLength) {
        return OTS_FAILURE_MSG("Invalid GlyphVariationData offset");
      }
      if (!ParseVariationData(font, glyphVariationData + prevOffset,
                              glyphVariationDataLength - prevOffset,
                              axisCount, sharedTupleCount)) {
        return OTS_FAILURE_MSG("Failed to parse GlyphVariationData");
      }
    }
    prevOffset = offset;
  }

  return true;
}

bool OpenTypeGVAR::Parse(const uint8_t* data, size_t length) {
  Buffer table(data, length);

  uint16_t majorVersion;
  uint16_t minorVersion;
  uint16_t axisCount;
  uint16_t sharedTupleCount;
  uint32_t sharedTuplesOffset;
  uint16_t glyphCount;
  uint16_t flags;
  uint32_t glyphVariationDataArrayOffset;

  if (!table.ReadU16(&majorVersion) ||
      !table.ReadU16(&minorVersion) ||
      !table.ReadU16(&axisCount) ||
      !table.ReadU16(&sharedTupleCount) ||
      !table.ReadU32(&sharedTuplesOffset) ||
      !table.ReadU16(&glyphCount) ||
      !table.ReadU16(&flags) ||
      !table.ReadU32(&glyphVariationDataArrayOffset)) {
    return DropVariations("Failed to read table header");
  }
  if (majorVersion != 1) {
    return DropVariations("Unknown table version");
  }

  // check axisCount == fvar->axisCount
  OpenTypeFVAR* fvar = static_cast<OpenTypeFVAR*>(
      GetFont()->GetTypedTable(OTS_TAG_FVAR));
  if (!fvar) {
    return DropVariations("Required fvar table is missing");
  }
  if (axisCount != fvar->AxisCount()) {
    return DropVariations("Axis count mismatch");
  }

  // check glyphCount == maxp->num_glyphs
  OpenTypeMAXP* maxp = static_cast<OpenTypeMAXP*>(
      GetFont()->GetTypedTable(OTS_TAG_MAXP));
  if (!maxp) {
    return DropVariations("Required maxp table is missing");
  }
  if (glyphCount != maxp->num_glyphs) {
    return DropVariations("Glyph count mismatch");
  }

  if (sharedTupleCount > 0) {
    if (sharedTuplesOffset < table.offset() || sharedTuplesOffset > length) {
      return DropVariations("Invalid sharedTuplesOffset");
    }
    if (!ParseSharedTuples(GetFont(),
                           data + sharedTuplesOffset, length - sharedTuplesOffset,
                           sharedTupleCount, axisCount)) {
      return DropVariations("Failed to parse shared tuples");
    }
  }

  if (glyphVariationDataArrayOffset) {
    if (glyphVariationDataArrayOffset > length) {
      return DropVariations("Invalid glyphVariationDataArrayOffset");
    }
    if (!ParseGlyphVariationDataArray(GetFont(),
                                      data + table.offset(), length - table.offset(),
                                      flags, glyphCount, axisCount, sharedTupleCount,
                                      data + glyphVariationDataArrayOffset,
                                      length - glyphVariationDataArrayOffset)) {
      return DropVariations("Failed to read glyph variation data array");
    }
  }

  this->m_data = data;
  this->m_length = length;

  return true;
}

bool OpenTypeGVAR::Serialize(OTSStream* out) {
  if (!out->Write(this->m_data, this->m_length)) {
    return Error("Failed to write gvar table");
  }

  return true;
}

}  // namespace ots

#undef TABLE_NAME