Move kenlm up one level, simplify compilation

1 files changed, 40 insertions, 0 deletions

diff --git a/util/bit_packing.cc b/util/bit_packing.cc
new file mode 100644
index 000000000..41999b726
--- /dev/null
+++ b/util/bit_packing.cc
@@ -0,0 +1,40 @@
+#include "util/bit_packing.hh"
+#include "util/exception.hh"
+
+#include <string.h>
+
+namespace util {
+
+namespace {
+template <bool> struct StaticCheck {};
+template <> struct StaticCheck<true> { typedef bool StaticAssertionPassed; };
+
+// If your float isn't 4 bytes, we're hosed.  
+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 FloatEnc neg1 = { -1.0 }, pos1 = { 1.0 };
+  if ((neg1.i ^ pos1.i) != 0x80000000) UTIL_THROW(Exception, "Sign bit is not 0x80000000");
+  char mem[57+8];
+  memset(mem, 0, sizeof(mem));
+  const uint64_t test57 = 0x123456789abcdefULL;
+  for (uint64_t b = 0; b < 57 * 8; b += 57) {
+    WriteInt57(mem, b, 57, test57);
+  }
+  for (uint64_t b = 0; b < 57 * 8; b += 57) {
+    if (test57 != ReadInt57(mem, b, 57, (1ULL << 57) - 1))
+      UTIL_THROW(Exception, "The bit packing routines are failing for your architecture.  Please send a bug report with your architecture, operating system, and compiler.");
+  }
+  // TODO: more checks.  
+}
+
+} // namespace util