Fix MSVC warnings about possible value truncation.

src/ltsh.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 "ltsh.h"
 
 #include "maxp.h"
 
 // LTSH - Linear Threshold
 // http://www.microsoft.com/typography/otspec/ltsh.htm
@@ skipping 43 matching lines @@
   return true;
 }
 
 bool ots_ltsh_should_serialise(OpenTypeFile *file) {
   if (!file->glyf) return false;  // this table is not for CFF fonts.
   return file->ltsh != NULL;
 }
 
 bool ots_ltsh_serialise(OTSStream *out, OpenTypeFile *file) {
   const OpenTypeLTSH *ltsh = file->ltsh;
-
-  if (!out->WriteU16(ltsh->version) ||
-      !out->WriteU16(ltsh->ypels.size())) {
+  const uint16_t num_ypels = static_cast<uint16_t>(ltsh->ypels.size());
+  if (num_ypels != ltsh->ypels.size() ||
+      !out->WriteU16(ltsh->version) ||
+      !out->WriteU16(num_ypels)) {
     return OTS_FAILURE();
   }
-  for (unsigned i = 0; i < ltsh->ypels.size(); ++i) {
+  for (uint16_t i = 0; i < num_ypels; ++i) {
     if (!out->Write(&(ltsh->ypels[i]), 1)) {
       return OTS_FAILURE();
     }
   }
 
   return true;
 }
 
 void ots_ltsh_free(OpenTypeFile *file) {
   delete file->ltsh;
 }
 
 }  // namespace ots