1 files changed, 120 insertions, 0 deletions
diff --git a/gfx/ots/src/hdmx.cc b/gfx/ots/src/hdmx.cc
new file mode 100644
index 0000000000..42ac9de8de
--- /dev/null
+++ b/gfx/ots/src/hdmx.cc
@@ -0,0 +1,120 @@
+// 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 "hdmx.h"
+#include "head.h"
+#include "maxp.h"
+
+// hdmx - Horizontal Device Metrics
+// http://www.microsoft.com/typography/otspec/hdmx.htm
+
+namespace ots {
+
+bool OpenTypeHDMX::Parse(const uint8_t *data, size_t length) {
+  Buffer table(data, length);
+
+  OpenTypeMAXP *maxp = static_cast<OpenTypeMAXP*>(
+      GetFont()->GetTypedTable(OTS_TAG_MAXP));
+  OpenTypeHEAD *head = static_cast<OpenTypeHEAD*>(
+      GetFont()->GetTypedTable(OTS_TAG_HEAD));
+  if (!head || !maxp) {
+    return Error("Missing maxp or head tables in font, needed by hdmx");
+  }
+
+  if ((head->flags & 0x14) == 0) {
+    // http://www.microsoft.com/typography/otspec/recom.htm#hdmx
+    return Drop("the table should not be present when bit 2 and 4 of the "
+                "head->flags are not set");
+  }
+
+  int16_t num_recs;
+  if (!table.ReadU16(&this->version) ||
+      !table.ReadS16(&num_recs) ||
+      !table.ReadS32(&this->size_device_record)) {
+    return Error("Failed to read table header");
+  }
+  if (this->version != 0) {
+    return Drop("Unsupported version: %u", this->version);
+  }
+  if (num_recs <= 0) {
+    return Drop("Bad numRecords: %d", num_recs);
+  }
+  const int32_t actual_size_device_record = maxp->num_glyphs + 2;
+  if (this->size_device_record < actual_size_device_record) {
+    return Drop("Bad sizeDeviceRecord: %d", this->size_device_record);
+  }
+
+  this->pad_len = this->size_device_record - actual_size_device_record;
+  if (this->pad_len > 3) {
+    return Error("Bad DeviceRecord padding %d", this->pad_len);
+  }
+
+  uint8_t last_pixel_size = 0;
+  this->records.reserve(num_recs);
+  for (int i = 0; i < num_recs; ++i) {
+    OpenTypeHDMXDeviceRecord rec;
+
+    if (!table.ReadU8(&rec.pixel_size) ||
+        !table.ReadU8(&rec.max_width)) {
+      return Error("Failed to read DeviceRecord %d", i);
+    }
+    if ((i != 0) &&
+        (rec.pixel_size <= last_pixel_size)) {
+      return Drop("DeviceRecord's are not sorted");
+    }
+    last_pixel_size = rec.pixel_size;
+
+    rec.widths.reserve(maxp->num_glyphs);
+    for (unsigned j = 0; j < maxp->num_glyphs; ++j) {
+      uint8_t width;
+      if (!table.ReadU8(&width)) {
+        return Error("Failed to read glyph width %d in DeviceRecord %d", j, i);
+      }
+      rec.widths.push_back(width);
+    }
+
+    if ((this->pad_len > 0) &&
+        !table.Skip(this->pad_len)) {
+      return Error("DeviceRecord %d should be padded by %d", i, this->pad_len);
+    }
+
+    this->records.push_back(rec);
+  }
+
+  return true;
+}
+
+bool OpenTypeHDMX::ShouldSerialize() {
+  return Table::ShouldSerialize() &&
+         // this table is not for CFF fonts.
+         GetFont()->GetTable(OTS_TAG_GLYF) != NULL;
+}
+
+bool OpenTypeHDMX::Serialize(OTSStream *out) {
+  const int16_t num_recs = static_cast<int16_t>(this->records.size());
+  if (this->records.size() >
+          static_cast<size_t>(std::numeric_limits<int16_t>::max()) ||
+      !out->WriteU16(this->version) ||
+      !out->WriteS16(num_recs) ||
+      !out->WriteS32(this->size_device_record)) {
+    return Error("Failed to write table header");
+  }
+
+  for (int16_t i = 0; i < num_recs; ++i) {
+    const OpenTypeHDMXDeviceRecord& rec = this->records[i];
+    if (!out->Write(&rec.pixel_size, 1) ||
+        !out->Write(&rec.max_width, 1) ||
+        !out->Write(&rec.widths[0], rec.widths.size())) {
+      return Error("Failed to write DeviceRecord %d", i);
+    }
+    if ((this->pad_len > 0) &&
+        !out->Write((const uint8_t *)"\x00\x00\x00", this->pad_len)) {
+      return Error("Failed to write padding of length %d", this->pad_len);
+    }
+  }
+
+  return true;
+}
+
+}  // namespace ots