1 files changed, 107 insertions, 0 deletions
diff --git a/gfx/ots/src/mvar.cc b/gfx/ots/src/mvar.cc
new file mode 100644
index 0000000000..e485ec0488
--- /dev/null
+++ b/gfx/ots/src/mvar.cc
@@ -0,0 +1,107 @@
+// 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 "mvar.h"
+
+#include "variations.h"
+
+namespace ots {
+
+// -----------------------------------------------------------------------------
+// OpenTypeMVAR
+// -----------------------------------------------------------------------------
+
+bool OpenTypeMVAR::Parse(const uint8_t* data, size_t length) {
+  Buffer table(data, length);
+
+  uint16_t majorVersion;
+  uint16_t minorVersion;
+  uint16_t reserved;
+  uint16_t valueRecordSize;
+  uint16_t valueRecordCount;
+  uint16_t itemVariationStoreOffset;
+
+  if (!table.ReadU16(&majorVersion) ||
+      !table.ReadU16(&minorVersion) ||
+      !table.ReadU16(&reserved) ||
+      !table.ReadU16(&valueRecordSize) ||
+      !table.ReadU16(&valueRecordCount) ||
+      !table.ReadU16(&itemVariationStoreOffset)) {
+    return DropVariations("Failed to read table header");
+  }
+
+  if (majorVersion != 1) {
+    return DropVariations("Unknown table version");
+  }
+
+  if (reserved != 0) {
+    Warning("Expected reserved=0");
+  }
+
+  // The spec says that valueRecordSize "must be greater than zero",
+  // but we don't enforce this in the case where valueRecordCount
+  // is zero.
+  // The minimum size for a valueRecord to be valid is 8, for the
+  // three fields currently defined in the record (see below).
+  if (valueRecordSize < 8) {
+    if (valueRecordCount != 0) {
+      return DropVariations("Value record size too small");
+    }
+  }
+
+  if (valueRecordCount == 0) {
+    if (itemVariationStoreOffset != 0) {
+      // The spec says "if valueRecordCount is zero, set to zero",
+      // but having a variation store even when record count is zero
+      // should be harmless -- it just won't be useful for anything.
+      // But we don't need to reject altogether.
+      Warning("Unexpected item variation store");
+    }
+  } else {
+    if (itemVariationStoreOffset < table.offset() || itemVariationStoreOffset > length) {
+      return DropVariations("Invalid item variation store offset");
+    }
+    if (!ParseItemVariationStore(GetFont(), data + itemVariationStoreOffset,
+                                 length - itemVariationStoreOffset)) {
+      return DropVariations("Failed to parse item variation store");
+    }
+  }
+
+  uint32_t prevTag = 0;
+  size_t offset = table.offset();
+  for (unsigned i = 0; i < valueRecordCount; i++) {
+    uint32_t tag;
+    uint16_t deltaSetOuterIndex, deltaSetInnerIndex;
+    if (!table.ReadU32(&tag) ||
+        !table.ReadU16(&deltaSetOuterIndex) ||
+        !table.ReadU16(&deltaSetInnerIndex)) {
+      return DropVariations("Failed to read value record");
+    }
+    if (tag <= prevTag) {
+      return DropVariations(
+        "Out-of-order value tag: '%c%c%c%c', previous tag: '%c%c%c%c'",
+        OTS_UNTAG(tag), OTS_UNTAG(prevTag));
+    }
+    prevTag = tag;
+    // Adjust offset in case additional fields have been added to the
+    // valueRecord by a new minor version (allowed by spec).
+    offset += valueRecordSize;
+    table.set_offset(offset);
+  }
+
+  this->m_data = data;
+  this->m_length = length;
+
+  return true;
+}
+
+bool OpenTypeMVAR::Serialize(OTSStream* out) {
+  if (!out->Write(this->m_data, this->m_length)) {
+    return Error("Failed to write MVAR table");
+  }
+
+  return true;
+}
+
+}  // namespace ots