1 files changed, 155 insertions, 0 deletions
diff --git a/gfx/ots/src/vdmx.cc b/gfx/ots/src/vdmx.cc
new file mode 100644
index 0000000000..54055777a8
--- /dev/null
+++ b/gfx/ots/src/vdmx.cc
@@ -0,0 +1,155 @@
+// 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 "vdmx.h"
+
+// VDMX - Vertical Device Metrics
+// http://www.microsoft.com/typography/otspec/vdmx.htm
+
+namespace ots {
+
+bool OpenTypeVDMX::Parse(const uint8_t *data, size_t length) {
+  Buffer table(data, length);
+
+  if (!table.ReadU16(&this->version) ||
+      !table.ReadU16(&this->num_recs) ||
+      !table.ReadU16(&this->num_ratios)) {
+    return Error("Failed to read table header");
+  }
+
+  if (this->version > 1) {
+    return Drop("Unsupported table version: %u", this->version);
+  }
+
+  this->rat_ranges.reserve(this->num_ratios);
+  for (unsigned i = 0; i < this->num_ratios; ++i) {
+    OpenTypeVDMXRatioRecord rec;
+
+    if (!table.ReadU8(&rec.charset) ||
+        !table.ReadU8(&rec.x_ratio) ||
+        !table.ReadU8(&rec.y_start_ratio) ||
+        !table.ReadU8(&rec.y_end_ratio)) {
+      return Error("Failed to read RatioRange record %d", i);
+    }
+
+    if (rec.charset > 1) {
+      return Drop("Unsupported character set: %u", rec.charset);
+    }
+
+    if (rec.y_start_ratio > rec.y_end_ratio) {
+      return Drop("Bad y ratio");
+    }
+
+    // All values set to zero signal the default grouping to use;
+    // if present, this must be the last Ratio group in the table.
+    if ((i < this->num_ratios - 1u) &&
+        (rec.x_ratio == 0) &&
+        (rec.y_start_ratio == 0) &&
+        (rec.y_end_ratio == 0)) {
+      // workaround for fonts which have 2 or more {0, 0, 0} terminators.
+      return Drop("Superfluous terminator found");
+    }
+
+    this->rat_ranges.push_back(rec);
+  }
+
+  this->offsets.reserve(this->num_ratios);
+  const size_t current_offset = table.offset();
+  // current_offset is less than (2 bytes * 3) + (4 bytes * USHRT_MAX) = 256k.
+  for (unsigned i = 0; i < this->num_ratios; ++i) {
+    uint16_t offset;
+    if (!table.ReadU16(&offset)) {
+      return Error("Failed to read ratio offset %d", i);
+    }
+    if (current_offset + offset >= length) {  // thus doesn't overflow.
+      return Error("Bad ratio offset %d for ration %d", offset, i);
+    }
+
+    this->offsets.push_back(offset);
+  }
+
+  this->groups.reserve(this->num_recs);
+  for (unsigned i = 0; i < this->num_recs; ++i) {
+    OpenTypeVDMXGroup group;
+    if (!table.ReadU16(&group.recs) ||
+        !table.ReadU8(&group.startsz) ||
+        !table.ReadU8(&group.endsz)) {
+      return Error("Failed to read record header %d", i);
+    }
+    group.entries.reserve(group.recs);
+    for (unsigned j = 0; j < group.recs; ++j) {
+      OpenTypeVDMXVTable vt;
+      if (!table.ReadU16(&vt.y_pel_height) ||
+          !table.ReadS16(&vt.y_max) ||
+          !table.ReadS16(&vt.y_min)) {
+        return Error("Failed to read reacord %d group %d", i, j);
+      }
+      if (vt.y_max < vt.y_min) {
+        return Drop("bad y min/max");
+      }
+
+      // This table must appear in sorted order (sorted by yPelHeight),
+      // but need not be continuous.
+      if ((j != 0) && (group.entries[j - 1].y_pel_height >= vt.y_pel_height)) {
+        return Drop("The table is not sorted");
+      }
+
+      group.entries.push_back(vt);
+    }
+    this->groups.push_back(group);
+  }
+
+  return true;
+}
+
+bool OpenTypeVDMX::ShouldSerialize() {
+  return Table::ShouldSerialize() &&
+         // this table is not for CFF fonts.
+         GetFont()->GetTable(OTS_TAG_GLYF) != NULL;
+}
+
+bool OpenTypeVDMX::Serialize(OTSStream *out) {
+  if (!out->WriteU16(this->version) ||
+      !out->WriteU16(this->num_recs) ||
+      !out->WriteU16(this->num_ratios)) {
+    return Error("Failed to write table header");
+  }
+
+  for (unsigned i = 0; i < this->rat_ranges.size(); ++i) {
+    const OpenTypeVDMXRatioRecord& rec = this->rat_ranges[i];
+    if (!out->Write(&rec.charset, 1) ||
+        !out->Write(&rec.x_ratio, 1) ||
+        !out->Write(&rec.y_start_ratio, 1) ||
+        !out->Write(&rec.y_end_ratio, 1)) {
+      return Error("Failed to write RatioRange record %d", i);
+    }
+  }
+
+  for (unsigned i = 0; i < this->offsets.size(); ++i) {
+    if (!out->WriteU16(this->offsets[i])) {
+      return Error("Failed to write ratio offset %d", i);
+    }
+  }
+
+  for (unsigned i = 0; i < this->groups.size(); ++i) {
+    const OpenTypeVDMXGroup& group = this->groups[i];
+    if (!out->WriteU16(group.recs) ||
+        !out->Write(&group.startsz, 1) ||
+        !out->Write(&group.endsz, 1)) {
+      return Error("Failed to write group %d", i);
+    }
+    for (unsigned j = 0; j < group.entries.size(); ++j) {
+      const OpenTypeVDMXVTable& vt = group.entries[j];
+      if (!out->WriteU16(vt.y_pel_height) ||
+          !out->WriteS16(vt.y_max) ||
+          !out->WriteS16(vt.y_min)) {
+        return Error("Failed to write group %d entry %d", i, j);
+      }
+    }
+  }
+
+  return true;
+}
+
+}  // namespace ots