1 files changed, 209 insertions, 0 deletions
diff --git a/gfx/ots/src/gvar.cc b/gfx/ots/src/gvar.cc
new file mode 100644
index 0000000000..33e55ff5ef
--- /dev/null
+++ b/gfx/ots/src/gvar.cc
@@ -0,0 +1,209 @@
+// 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"
+#include "ots-memory-stream.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;
+}
+
+#ifdef OTS_SYNTHESIZE_MISSING_GVAR
+bool OpenTypeGVAR::InitEmpty() {
+  // Generate an empty but well-formed 'gvar' table for the font.
+  const ots::Font* font = GetFont();
+
+  OpenTypeFVAR* fvar = static_cast<OpenTypeFVAR*>(font->GetTypedTable(OTS_TAG_FVAR));
+  if (!fvar) {
+    return DropVariations("Required fvar table missing");
+  }
+
+  OpenTypeMAXP* maxp = static_cast<OpenTypeMAXP*>(font->GetTypedTable(OTS_TAG_MAXP));
+  if (!maxp) {
+    return DropVariations("Required maxp table missing");
+  }
+
+  uint16_t majorVersion = 1;
+  uint16_t minorVersion = 0;
+  uint16_t axisCount = fvar->AxisCount();
+  uint16_t sharedTupleCount = 0;
+  uint32_t sharedTuplesOffset = 0;
+  uint16_t glyphCount = maxp->num_glyphs;
+  uint16_t flags = 0;
+  uint32_t glyphVariationDataArrayOffset = 0;
+
+  size_t length = 6 * sizeof(uint16_t) + 2 * sizeof(uint32_t)  // basic header fields
+      + (glyphCount + 1) * sizeof(uint16_t);  // glyphVariationDataOffsets[] array
+
+  uint8_t* data = new uint8_t[length];
+  MemoryStream stream(data, length);
+  if (!stream.WriteU16(majorVersion) ||
+      !stream.WriteU16(minorVersion) ||
+      !stream.WriteU16(axisCount) ||
+      !stream.WriteU16(sharedTupleCount) ||
+      !stream.WriteU32(sharedTuplesOffset) ||
+      !stream.WriteU16(glyphCount) ||
+      !stream.WriteU16(flags) ||
+      !stream.WriteU32(glyphVariationDataArrayOffset) ||
+      !stream.Pad((glyphCount + 1) * sizeof(uint16_t))) {
+    delete[] data;
+    return DropVariations("Failed to generate dummy gvar table");
+  }
+
+  this->m_data = data;
+  this->m_length = length;
+  this->m_ownsData = true;
+
+  return true;
+}
+#endif
+
+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