[dpdk-dev] [PATCH v3 4/6] hash: add two new functions to jhash library
Pablo de Lara
pablo.de.lara.guarch at intel.com
Tue May 5 16:43:52 CEST 2015
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 at intel.com>
---
lib/librte_hash/rte_jhash.h | 195 +++++++++++++++++++++++++++++++++++++++++++
1 files changed, 195 insertions(+), 0 deletions(-)
diff --git a/lib/librte_hash/rte_jhash.h b/lib/librte_hash/rte_jhash.h
index 0e96b7c..9e82d06 100644
--- a/lib/librte_hash/rte_jhash.h
+++ b/lib/librte_hash/rte_jhash.h
@@ -292,6 +292,201 @@ 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 k
+ * Key to calculate hash of.
+ * @param length
+ * Length of key in bytes.
+ * @param pc
+ * IN: seed OUT: primary hash value.
+ * @param pc
+ * 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;
+ union {
+ const void *ptr;
+ size_t i;
+ } u;
+
+ /* Set up the internal state */
+ a = b = c = RTE_JHASH_GOLDEN_RATIO + ((uint32_t)length) + *pc;
+ c += *pb;
+
+ u.ptr = key;
+
+ /* Check key alignment. For x86 architecture, first case is always optimal */
+ if (!strcmp(RTE_ARCH,"x86_64") || !strcmp(RTE_ARCH,"i686") || (u.i & 0x3) == 0) {
+ const uint32_t *k = (const uint32_t *)key;
+
+ 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 {
+ const uint8_t *k = (const uint8_t *)key;
+
+ /* all but the last block: affect some 32 bits of (a, b, c) */
+ while (length > 12) {
+ a += ((uint32_t)k[0]) << RTE_JHASH_BYTE0_SHIFT;
+ a += ((uint32_t)k[1]) << RTE_JHASH_BYTE1_SHIFT;
+ a += ((uint32_t)k[2]) << RTE_JHASH_BYTE2_SHIFT;
+ a += ((uint32_t)k[3]) << RTE_JHASH_BYTE3_SHIFT;
+ b += ((uint32_t)k[4]) << RTE_JHASH_BYTE0_SHIFT;
+ b += ((uint32_t)k[5]) << RTE_JHASH_BYTE1_SHIFT;
+ b += ((uint32_t)k[6]) << RTE_JHASH_BYTE2_SHIFT;
+ b += ((uint32_t)k[7]) << RTE_JHASH_BYTE3_SHIFT;
+ c += ((uint32_t)k[8]) << RTE_JHASH_BYTE0_SHIFT;
+ c += ((uint32_t)k[9]) << RTE_JHASH_BYTE1_SHIFT;
+ c += ((uint32_t)k[10]) << RTE_JHASH_BYTE2_SHIFT;
+ c += ((uint32_t)k[11]) << RTE_JHASH_BYTE3_SHIFT;
+
+ __rte_jhash_mix(a, b, c);
+
+ k += 12;
+ length -= 12;
+ }
+
+ /* last block: affect all 32 bits of (c) */
+ /* all the case statements fall through */
+ switch (length) {
+ case 12:
+ c += ((uint32_t)k[11]) << RTE_JHASH_BYTE3_SHIFT;
+ case 11:
+ c += ((uint32_t)k[10]) << RTE_JHASH_BYTE2_SHIFT;
+ case 10:
+ c += ((uint32_t)k[9]) << RTE_JHASH_BYTE1_SHIFT;
+ case 9:
+ c += ((uint32_t)k[8]) << RTE_JHASH_BYTE0_SHIFT;
+ case 8:
+ b += ((uint32_t)k[7]) << RTE_JHASH_BYTE3_SHIFT;
+ case 7:
+ b += ((uint32_t)k[6]) << RTE_JHASH_BYTE2_SHIFT;
+ case 6:
+ b += ((uint32_t)k[5]) << RTE_JHASH_BYTE1_SHIFT;
+ case 5:
+ b += ((uint32_t)k[4]) << RTE_JHASH_BYTE0_SHIFT;
+ case 4:
+ a += ((uint32_t)k[3]) << RTE_JHASH_BYTE3_SHIFT;
+ case 3:
+ a += ((uint32_t)k[2]) << RTE_JHASH_BYTE2_SHIFT;
+ case 2:
+ a += ((uint32_t)k[1]) << RTE_JHASH_BYTE1_SHIFT;
+ case 1:
+ a += ((uint32_t)k[0]) << RTE_JHASH_BYTE0_SHIFT;
+ break;
+ 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 pc
+ * 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];
+ case 2:
+ b += k[1];
+ case 1:
+ a += k[0];
+ __rte_jhash_final(a, b, c);
+ /* 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)
{
--
1.7.4.1
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