Fix reading and writing format 13 cmap tables

src/cmap.cc

Index: src/cmap.cc
diff --git a/src/cmap.cc b/src/cmap.cc
index 66be75de24fabe517c7060d773d4844309807e97..03ba7e1505aed38073a491affa9e4621114f202a 100644
--- a/src/cmap.cc
+++ b/src/cmap.cc
@@ -351,8 +351,8 @@ bool Parse31013(ots::OpenTypeFile *file,
   if (!subtable.Skip(8)) {
     return OTS_FAILURE();
   }
-  uint16_t language = 0;
-  if (!subtable.ReadU16(&language)) {
+  uint32_t language = 0;
+  if (!subtable.ReadU32(&language)) {
     return OTS_FAILURE();
   }
   if (language) {
@@ -982,7 +982,7 @@ bool ots_cmap_serialise(OTSStream *out, OpenTypeFile *file) {
     const unsigned num_groups = groups.size();
     if (!out->WriteU16(13) ||
         !out->WriteU16(0) ||
-        !out->WriteU32(num_groups * 12 + 14) ||
+        !out->WriteU32(num_groups * 12 + 16) ||
         !out->WriteU32(0) ||
         !out->WriteU32(num_groups)) {
       return OTS_FAILURE();