[OTS] Integrate WOFF 2.0 algorithm into OTS

src/ots.h

Index: src/ots.h
===================================================================
--- src/ots.h	(revision 99)
+++ src/ots.h	(working copy)
@@ -11,9 +11,15 @@
 #include <cstdio>
 #include <cstdlib>
 #include <cstring>
+#include <limits>
 
 #include "opentype-sanitiser.h"
 
+// arraysize borrowed from base/basictypes.h
+template <typename T, size_t N>
+char (&ArraySizeHelper(T (&array)[N]))[N];
+#define arraysize(array) (sizeof(ArraySizeHelper(array)))
+
 namespace ots {
 
 #if defined(_MSC_VER) || !defined(OTS_DEBUG)
@@ -158,6 +164,17 @@
   size_t offset_;
 };
 
+// Round a value up to the nearest multiple of 4. Don't round the value in the
+// case that rounding up overflows.
+template<typename T> T Round4(T value) {
+  if (std::numeric_limits<T>::max() - value < 3) {
+    return value;
+  }
+  return (value + 3) & ~3;
+}
+
+bool IsValidVersionTag(uint32_t tag);
+
 #define FOR_EACH_TABLE_TYPE \
   F(cff, CFF) \
   F(cmap, CMAP) \