Fix MSVC warnings about possible value truncation.

src/vorg.cc

 // Copyright (c) 2009 The Chromium 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 "vorg.h"
 
 #include <vector>
 
 // VORG - Vertical Origin Table
 // http://www.microsoft.com/opentype/otspec/vorg.htm
@@ skipping 53 matching lines @@
   return true;
 }
 
 bool ots_vorg_should_serialise(OpenTypeFile *file) {
   if (!file->cff) return false;  // this table is not for fonts with TT glyphs.
   return file->vorg != NULL;
 }
 
 bool ots_vorg_serialise(OTSStream *out, OpenTypeFile *file) {
   OpenTypeVORG * const vorg = file->vorg;
-
-  if (!out->WriteU16(vorg->major_version) ||
+  
+  const uint16_t num_metrics = static_cast<uint16_t>(vorg->metrics.size());
+  if (num_metrics != vorg->metrics.size() ||
+      !out->WriteU16(vorg->major_version) ||
       !out->WriteU16(vorg->minor_version) ||
       !out->WriteS16(vorg->default_vert_origin_y) ||
-      !out->WriteU16(vorg->metrics.size())) {
+      !out->WriteU16(num_metrics)) {
     return OTS_FAILURE();
   }
 
-  for (unsigned i = 0; i < vorg->metrics.size(); ++i) {
+  for (uint16_t i = 0; i < num_metrics; ++i) {
     const OpenTypeVORGMetrics& rec = vorg->metrics[i];
     if (!out->WriteU16(rec.glyph_index) ||
         !out->WriteS16(rec.vert_origin_y)) {
       return OTS_FAILURE();
     }
   }
 
   return true;
 }
 
 void ots_vorg_free(OpenTypeFile *file) {
   delete file->vorg;
 }
 
 }  // namespace ots