hash: add new jhash functions

With the jhash update, two new functions were introduced:

- rte_jhash_2hashes: Same as rte_jhash, but takes two seeds
                     and return two hashes (uint32_ts)

- rte_jhash2_2hashes: Same as rte_jhash2, but takes two seeds
                     and return two hashes (uint32_ts)

Signed-off-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
[Thomas: fix doxygen typos]

diff --git a/lib/librte_hash/rte_jhash.h b/lib/librte_hash/rte_jhash.h
index 1cb5c44..62e276c 100644 (file)
--- a/lib/librte_hash/rte_jhash.h
+++ b/lib/librte_hash/rte_jhash.h
@@ -300,6 +300,215 @@ rte_jhash2(const uint32_t *k, uint32_t length, uint32_t initval)
        return c;
 }
 
+/**
+ * Same as rte_jhash, but takes two seeds and return two uint32_ts.
+ * pc and pb must be non-null, and *pc and *pb must both be initialized
+ * with seeds. If you pass in (*pb)=0, the output (*pc) will be
+ * the same as the return value from rte_jhash.
+ *
+ * @param key
+ *   Key to calculate hash of.
+ * @param length
+ *   Length of key in bytes.
+ * @param pc
+ *   IN: seed OUT: primary hash value.
+ * @param pb
+ *   IN: second seed OUT: secondary hash value.
+ */
+static inline void
+rte_jhash_2hashes(const void *key, uint32_t length, uint32_t *pc, uint32_t *pb)
+{
+       uint32_t a, b, c;
+
+       /* Set up the internal state */
+       a = b = c = RTE_JHASH_GOLDEN_RATIO + ((uint32_t)length) + *pc;
+       c += *pb;
+
+       /* Check key alignment. For x86 architecture, first case is always optimal */
+#if defined(RTE_ARCH_X86_64) || defined(RTE_ARCH_I686) || defined(RTE_ARCH_X86_X32)
+       const uint32_t *k = key;
+       const uint32_t s = 0;
+#else
+       const uint32_t *k = (uint32_t *)(uintptr_t)key & (uintptr_t)~3);
+       const uint32_t s = ((uintptr_t)key & 3) * CHAR_BIT;
+#endif
+
+       if (s == 0) {
+               while (length > 12) {
+                       a += k[0];
+                       b += k[1];
+                       c += k[2];
+
+                       __rte_jhash_mix(a, b, c);
+
+                       k += 3;
+                       length -= 12;
+               }
+
+               switch (length) {
+               case 12:
+                       c += k[2]; b += k[1]; a += k[0]; break;
+               case 11:
+                       c += k[2] & LOWER24b_MASK; b += k[1]; a += k[0]; break;
+               case 10:
+                       c += k[2] & LOWER16b_MASK; b += k[1]; a += k[0]; break;
+               case 9:
+                       c += k[2] & LOWER8b_MASK; b += k[1]; a += k[0]; break;
+               case 8:
+                       b += k[1]; a += k[0]; break;
+               case 7:
+                       b += k[1] & LOWER24b_MASK; a += k[0]; break;
+               case 6:
+                       b += k[1] & LOWER16b_MASK; a += k[0]; break;
+               case 5:
+                       b += k[1] & LOWER8b_MASK; a += k[0]; break;
+               case 4:
+                       a += k[0]; break;
+               case 3:
+                       a += k[0] & LOWER24b_MASK; break;
+               case 2:
+                       a += k[0] & LOWER16b_MASK; break;
+               case 1:
+                       a += k[0] & LOWER8b_MASK; break;
+               /* zero length strings require no mixing */
+               case 0:
+                       *pc = c;
+                       *pb = b;
+                       return;
+               };
+       } else {
+               /* all but the last block: affect some 32 bits of (a, b, c) */
+               while (length > 12) {
+                       a += BIT_SHIFT(k[0], k[1], s);
+                       b += BIT_SHIFT(k[1], k[2], s);
+                       c += BIT_SHIFT(k[2], k[3], s);
+                       __rte_jhash_mix(a, b, c);
+
+                       k += 3;
+                       length -= 12;
+               }
+
+               /* last block: affect all 32 bits of (c) */
+               switch (length) {
+               case 12:
+                       a += BIT_SHIFT(k[0], k[1], s);
+                       b += BIT_SHIFT(k[1], k[2], s);
+                       c += BIT_SHIFT(k[2], k[3], s);
+                       break;
+               case 11:
+                       a += BIT_SHIFT(k[0], k[1], s);
+                       b += BIT_SHIFT(k[1], k[2], s);
+                       c += BIT_SHIFT(k[2], k[3], s) & LOWER24b_MASK;
+                       break;
+               case 10:
+                       a += BIT_SHIFT(k[0], k[1], s);
+                       b += BIT_SHIFT(k[1], k[2], s);
+                       c += BIT_SHIFT(k[2], k[3], s) & LOWER16b_MASK;
+                       break;
+               case 9:
+                       a += BIT_SHIFT(k[0], k[1], s);
+                       b += BIT_SHIFT(k[1], k[2], s);
+                       c += BIT_SHIFT(k[2], k[3], s) & LOWER8b_MASK;
+                       break;
+               case 8:
+                       a += BIT_SHIFT(k[0], k[1], s);
+                       b += BIT_SHIFT(k[1], k[2], s);
+                       break;
+               case 7:
+                       a += BIT_SHIFT(k[0], k[1], s);
+                       b += BIT_SHIFT(k[1], k[2], s) & LOWER24b_MASK;
+                       break;
+               case 6:
+                       a += BIT_SHIFT(k[0], k[1], s);
+                       b += BIT_SHIFT(k[1], k[2], s) & LOWER16b_MASK;
+                       break;
+               case 5:
+                       a += BIT_SHIFT(k[0], k[1], s);
+                       b += BIT_SHIFT(k[1], k[2], s) & LOWER8b_MASK;
+                       break;
+               case 4:
+                       a += BIT_SHIFT(k[0], k[1], s);
+                       break;
+               case 3:
+                       a += BIT_SHIFT(k[0], k[1], s) & LOWER24b_MASK;
+                       break;
+               case 2:
+                       a += BIT_SHIFT(k[0], k[1], s) & LOWER16b_MASK;
+                       break;
+               case 1:
+                       a += BIT_SHIFT(k[0], k[1], s) & LOWER8b_MASK;
+                       break;
+               /* zero length strings require no mixing */
+               case 0:
+                       *pc = c;
+                       *pb = b;
+                       return;
+               }
+       }
+
+       __rte_jhash_final(a, b, c);
+
+       *pc = c;
+       *pb = b;
+}
+
+/**
+ * Same as rte_jhash2, but takes two seeds and return two uint32_ts.
+ * pc and pb must be non-null, and *pc and *pb must both be initialized
+ * with seeds. If you pass in (*pb)=0, the output (*pc) will be
+ * the same as the return value from rte_jhash2.
+ *
+ * @param k
+ *   Key to calculate hash of.
+ * @param length
+ *   Length of key in units of 4 bytes.
+ * @param pc
+ *   IN: seed OUT: primary hash value.
+ * @param pb
+ *   IN: second seed OUT: secondary hash value.
+ */
+static inline void
+rte_jhash2_2hashes(const uint32_t *k, uint32_t length, uint32_t *pc, uint32_t *pb)
+{
+       uint32_t a, b, c;
+
+       /* Set up the internal state */
+       a = b = c = RTE_JHASH_GOLDEN_RATIO + (((uint32_t)length) << 2) + *pc;
+       c += *pb;
+
+       /* Handle most of the key */
+       while (length > 3) {
+               a += k[0];
+               b += k[1];
+               c += k[2];
+
+               __rte_jhash_mix(a, b, c);
+
+               k += 3;
+               length -= 3;
+       }
+
+       /* Handle the last 3 uint32_t's */
+       switch (length) {
+       case 3:
+               c += k[2];
+               /* Fallthrough */
+       case 2:
+               b += k[1];
+               /* Fallthrough */
+       case 1:
+               a += k[0];
+               __rte_jhash_final(a, b, c);
+               /* Fallthrough */
+       /* case 0: nothing left to add */
+       case 0:
+               break;
+       };
+
+       *pc = c;
+       *pb = b;
+}
+
 static inline uint32_t
 __rte_jhash_3words(uint32_t a, uint32_t b, uint32_t c, uint32_t initval)
 {