Add _hb_bit_storage()
diff --git a/src/hb-private.h b/src/hb-private.h
index f017bf9..78d2bf1 100644
--- a/src/hb-private.h
+++ b/src/hb-private.h
@@ -136,27 +136,36 @@
#endif
-/* Return the number of 1 bits in mask.
- *
- * GCC 3.4 supports a "population count" builtin, which on many targets is
- * implemented with a single instruction. There is a fallback definition
- * in libgcc in case a target does not have one, which should be just as
- * good as the open-coded solution below, (which is "HACKMEM 169").
- */
+/* Return the number of 1 bits in mask. */
static inline HB_CONST_FUNC unsigned int
_hb_popcount32 (uint32_t mask)
{
#if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)
- return __builtin_popcount (mask);
+ return __builtin_popcount (mask);
#else
- register uint32_t y;
-
- y = (mask >> 1) &033333333333;
- y = mask - y - ((y >>1) & 033333333333);
- return (((y + (y >> 3)) & 030707070707) % 077);
+ /* "HACKMEM 169" */
+ register uint32_t y;
+ y = (mask >> 1) &033333333333;
+ y = mask - y - ((y >>1) & 033333333333);
+ return (((y + (y >> 3)) & 030707070707) % 077);
#endif
}
+/* Returns the number of bits needed to store number */
+static inline HB_CONST_FUNC unsigned int
+_hb_bit_storage (unsigned int number)
+{
+#if defined(__GNUC__) && (__GNUC__ >= 4) && defined(__OPTIMIZE__)
+ return likely (number) ? (sizeof (unsigned int) * 8 - __builtin_clzl(number)) : 0;
+#else
+ register unsigned int n_bits = 0;
+ while (number) {
+ n_bits++;
+ number >>= 1;
+ }
+ return n_bits;
+#endif
+}
/* We need external help for these */
