+
+/*
+ * Bob Jenkins jhash
+ */
+
+#define JHASH_INITVAL GOLDEN_RATIO_32
+
+static inline uint32_t rol32(uint32_t word, uint32_t shift)
+{
+ return (word << shift) | (word >> (32 - shift));
+}
+
+/* __jhash_mix -- mix 3 32-bit values reversibly. */
+#define __jhash_mix(a, b, c) \
+{ \
+ a -= c; a ^= rol32(c, 4); c += b; \
+ b -= a; b ^= rol32(a, 6); a += c; \
+ c -= b; c ^= rol32(b, 8); b += a; \
+ a -= c; a ^= rol32(c, 16); c += b; \
+ b -= a; b ^= rol32(a, 19); a += c; \
+ c -= b; c ^= rol32(b, 4); b += a; \
+}
+
+/* __jhash_final - final mixing of 3 32-bit values (a,b,c) into c */
+#define __jhash_final(a, b, c) \
+{ \
+ c ^= b; c -= rol32(b, 14); \
+ a ^= c; a -= rol32(c, 11); \
+ b ^= a; b -= rol32(a, 25); \
+ c ^= b; c -= rol32(b, 16); \
+ a ^= c; a -= rol32(c, 4); \
+ b ^= a; b -= rol32(a, 14); \
+ c ^= b; c -= rol32(b, 24); \
+}
+
+static inline uint32_t jhash(const void *key, uint32_t length, uint32_t initval)
+{
+ const uint8_t *k = key;
+ uint32_t a, b, c;
+
+ /* Set up the internal state */
+ a = b = c = JHASH_INITVAL + length + initval;
+
+ /* All but the last block: affect some 32 bits of (a,b,c) */
+ while (length > 12) {
+ a += *k;
+ b += *(k + 4);
+ c += *(k + 8);
+ __jhash_mix(a, b, c);
+ length -= 12;
+ k += 12;
+ }
+
+ /* Last block: affect all 32 bits of (c) */
+ /* All the case statements fall through */
+ switch (length) {
+ case 12: c += (uint32_t) k[11] << 24; fallthrough;
+ case 11: c += (uint32_t) k[10] << 16; fallthrough;
+ case 10: c += (uint32_t) k[9] << 8; fallthrough;
+ case 9: c += k[8]; fallthrough;
+ case 8: b += (uint32_t) k[7] << 24; fallthrough;
+ case 7: b += (uint32_t) k[6] << 16; fallthrough;
+ case 6: b += (uint32_t) k[5] << 8; fallthrough;
+ case 5: b += k[4]; fallthrough;
+ case 4: a += (uint32_t) k[3] << 24; fallthrough;
+ case 3: a += (uint32_t) k[2] << 16; fallthrough;
+ case 2: a += (uint32_t) k[1] << 8; fallthrough;
+ case 1: a += k[0];
+ __jhash_final(a, b, c);
+ fallthrough;
+ case 0: /* Nothing left to add */
+ break;
+ }
+
+ return c;
+}
+