1 files changed, 132 insertions, 0 deletions
diff --git a/gfx/ots/src/head.cc b/gfx/ots/src/head.cc
new file mode 100644
index 0000000000..6088504c8b
--- /dev/null
+++ b/gfx/ots/src/head.cc
@@ -0,0 +1,132 @@
+// Copyright (c) 2009-2017 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 "head.h"
+
+#include <cstring>
+
+// head - Font Header
+// http://www.microsoft.com/typography/otspec/head.htm
+
+namespace ots {
+
+bool OpenTypeHEAD::Parse(const uint8_t *data, size_t length) {
+  Buffer table(data, length);
+
+  uint32_t version = 0;
+  if (!table.ReadU32(&version) ||
+      !table.ReadU32(&this->revision)) {
+    return Error("Failed to read table header");
+  }
+
+  if (version >> 16 != 1) {
+    return Error("Unsupported majorVersion: %d", version >> 16);
+  }
+
+  // Skip the checksum adjustment
+  if (!table.Skip(4)) {
+    return Error("Failed to read checksum");
+  }
+
+  uint32_t magic;
+  if (!table.ReadU32(&magic) || magic != 0x5F0F3CF5) {
+    return Error("Failed to read or incorrect magicNumber");
+  }
+
+  if (!table.ReadU16(&this->flags)) {
+    return Error("Failed to read flags");
+  }
+
+  // We allow bits 0..4, 11..13
+  this->flags &= 0x381f;
+
+  if (!table.ReadU16(&this->upem)) {
+    return Error("Failed to read unitsPerEm");
+  }
+
+  // upem must be in range
+  if (this->upem < 16 ||
+      this->upem > 16384) {
+    return Error("unitsPerEm on in the range [16, 16384]: %d", this->upem);
+  }
+
+  if (!table.ReadR64(&this->created) ||
+      !table.ReadR64(&this->modified)) {
+    return Error("Can't read font dates");
+  }
+
+  if (!table.ReadS16(&this->xmin) ||
+      !table.ReadS16(&this->ymin) ||
+      !table.ReadS16(&this->xmax) ||
+      !table.ReadS16(&this->ymax)) {
+    return Error("Failed to read font bounding box");
+  }
+
+  if (this->xmin > this->xmax) {
+    return Error("Bad x dimension in the font bounding box (%d, %d)",
+                  this->xmin, this->xmax);
+  }
+  if (this->ymin > this->ymax) {
+    return Error("Bad y dimension in the font bounding box (%d, %d)",
+                  this->ymin, this->ymax);
+  }
+
+  if (!table.ReadU16(&this->mac_style)) {
+    return Error("Failed to read macStyle");
+  }
+
+  // We allow bits 0..6
+  this->mac_style &= 0x7f;
+
+  if (!table.ReadU16(&this->min_ppem)) {
+    return Error("Failed to read lowestRecPPEM");
+  }
+
+  // We don't care about the font direction hint
+  if (!table.Skip(2)) {
+    return Error("Failed to read fontDirectionHint");
+  }
+
+  if (!table.ReadS16(&this->index_to_loc_format)) {
+    return Error("Failed to read indexToLocFormat");
+  }
+  if (this->index_to_loc_format < 0 ||
+      this->index_to_loc_format > 1) {
+    return Error("Bad indexToLocFormat %d", this->index_to_loc_format);
+  }
+
+  int16_t glyph_data_format;
+  if (!table.ReadS16(&glyph_data_format) ||
+      glyph_data_format) {
+    return Error("Failed to read or bad glyphDataFormat");
+  }
+
+  return true;
+}
+
+bool OpenTypeHEAD::Serialize(OTSStream *out) {
+  if (!out->WriteU32(0x00010000) ||
+      !out->WriteU32(this->revision) ||
+      !out->WriteU32(0) ||  // check sum not filled in yet
+      !out->WriteU32(0x5F0F3CF5) ||
+      !out->WriteU16(this->flags) ||
+      !out->WriteU16(this->upem) ||
+      !out->WriteR64(this->created) ||
+      !out->WriteR64(this->modified) ||
+      !out->WriteS16(this->xmin) ||
+      !out->WriteS16(this->ymin) ||
+      !out->WriteS16(this->xmax) ||
+      !out->WriteS16(this->ymax) ||
+      !out->WriteU16(this->mac_style) ||
+      !out->WriteU16(this->min_ppem) ||
+      !out->WriteS16(2) ||
+      !out->WriteS16(this->index_to_loc_format) ||
+      !out->WriteS16(0)) {
+    return Error("Failed to write table");
+  }
+
+  return true;
+}
+
+}  // namespace