+
+/* Returns an appropriate delimiter for inserting just before the 0-based item
+ * 'index' in a list that has 'total' items in it. */
+const char *
+english_list_delimiter(size_t index, size_t total)
+{
+ return (index == 0 ? ""
+ : index < total - 1 ? ", "
+ : total > 2 ? ", and "
+ : " and ");
+}
+
+/* Given a 32 bit word 'n', calculates floor(log_2('n')). This is equivalent
+ * to finding the bit position of the most significant one bit in 'n'. It is
+ * an error to call this function with 'n' == 0. */
+int
+log_2_floor(uint32_t n)
+{
+ assert(n);
+
+#if !defined(UINT_MAX) || !defined(UINT32_MAX)
+#error "Someone screwed up the #includes."
+#elif __GNUC__ >= 4 && UINT_MAX == UINT32_MAX
+ return 31 - __builtin_clz(n);
+#else
+ {
+ int log = 0;
+
+#define BIN_SEARCH_STEP(BITS) \
+ if (n >= (1 << BITS)) { \
+ log += BITS; \
+ n >>= BITS; \
+ }
+ BIN_SEARCH_STEP(16);
+ BIN_SEARCH_STEP(8);
+ BIN_SEARCH_STEP(4);
+ BIN_SEARCH_STEP(2);
+ BIN_SEARCH_STEP(1);
+#undef BIN_SEARCH_STEP
+ return log;
+ }
+#endif
+}