1 files changed, 27 insertions, 0 deletions
diff --git a/klm/util/bit_packing.cc b/klm/util/bit_packing.cc
new file mode 100644
index 00000000..dd14ffe1
--- /dev/null
+++ b/klm/util/bit_packing.cc
@@ -0,0 +1,27 @@
+#include "util/bit_packing.hh"
+#include "util/exception.hh"
+
+namespace util {
+
+namespace {
+template <bool> struct StaticCheck {};
+template <> struct StaticCheck<true> { typedef bool StaticAssertionPassed; };
+
+typedef StaticCheck<sizeof(float) == 4>::StaticAssertionPassed FloatSize;
+
+} // namespace
+
+uint8_t RequiredBits(uint64_t max_value) {
+  if (!max_value) return 0;
+  uint8_t ret = 1;
+  while (max_value >>= 1) ++ret;
+  return ret;
+}
+
+void BitPackingSanity() {
+  const detail::FloatEnc neg1 = { -1.0 }, pos1 = { 1.0 };
+  if ((neg1.i ^ pos1.i) != 0x80000000) UTIL_THROW(Exception, "Sign bit is not 0x80000000");
+  // TODO: more checks.  
+}
+
+} // namespace util