+struct prime_ent
+{
+ hashval_t prime;
+ hashval_t inv;
+ hashval_t inv_m2; /* inverse of prime-2 */
+ hashval_t shift;
+};
+
+static struct prime_ent const prime_tab[] = {
+ { 7, 0x24924925, 0x9999999b, 2 },
+ { 13, 0x3b13b13c, 0x745d1747, 3 },
+ { 31, 0x08421085, 0x1a7b9612, 4 },
+ { 61, 0x0c9714fc, 0x15b1e5f8, 5 },
+ { 127, 0x02040811, 0x0624dd30, 6 },
+ { 251, 0x05197f7e, 0x073260a5, 7 },
+ { 509, 0x01824366, 0x02864fc8, 8 },
+ { 1021, 0x00c0906d, 0x014191f7, 9 },
+ { 2039, 0x0121456f, 0x0161e69e, 10 },
+ { 4093, 0x00300902, 0x00501908, 11 },
+ { 8191, 0x00080041, 0x00180241, 12 },
+ { 16381, 0x000c0091, 0x00140191, 13 },
+ { 32749, 0x002605a5, 0x002a06e6, 14 },
+ { 65521, 0x000f00e2, 0x00110122, 15 },
+ { 131071, 0x00008001, 0x00018003, 16 },
+ { 262139, 0x00014002, 0x0001c004, 17 },
+ { 524287, 0x00002001, 0x00006001, 18 },
+ { 1048573, 0x00003001, 0x00005001, 19 },
+ { 2097143, 0x00004801, 0x00005801, 20 },
+ { 4194301, 0x00000c01, 0x00001401, 21 },
+ { 8388593, 0x00001e01, 0x00002201, 22 },
+ { 16777213, 0x00000301, 0x00000501, 23 },
+ { 33554393, 0x00001381, 0x00001481, 24 },
+ { 67108859, 0x00000141, 0x000001c1, 25 },
+ { 134217689, 0x000004e1, 0x00000521, 26 },
+ { 268435399, 0x00000391, 0x000003b1, 27 },
+ { 536870909, 0x00000019, 0x00000029, 28 },
+ { 1073741789, 0x0000008d, 0x00000095, 29 },
+ { 2147483647, 0x00000003, 0x00000007, 30 },
+ /* Avoid "decimal constant so large it is unsigned" for 4294967291. */
+ { 0xfffffffb, 0x00000006, 0x00000008, 31 }
+};
+
+/* The following function returns an index into the above table of the
+ nearest prime number which is greater than N, and near a power of two. */
+
+static unsigned int
+higher_prime_index (unsigned long n)
+{
+ unsigned int low = 0;
+ unsigned int high = sizeof(prime_tab) / sizeof(prime_tab[0]);