Replace murmurhash algorithm with Robert Jenkin's hash algorithm
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Upstream-Status: Pending
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From test result, murmurhash algorithm does not work in big endian
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processor, so replace it with Robert Jenkin's hash which has worked
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in linux kernel for many years and has more adaptability.
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Signed-off-by: Roy.Li <rongqing.li@windriver.com>
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---
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libfdproto/ostr.c | 192 +++++++++++++++++++++--------------------------------
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1 file changed, 74 insertions(+), 118 deletions(-)
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diff --git a/libfdproto/ostr.c b/libfdproto/ostr.c
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index 8f29b48..ce1f4dd 100644
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--- a/libfdproto/ostr.c
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+++ b/libfdproto/ostr.c
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@@ -430,128 +430,84 @@ after_proto:
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/********************************************************************************************************/
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-/* Hash function -- credits to Austin Appleby, thank you ^^ */
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-/* See http://murmurhash.googlepages.com for more information on this function */
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-
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-/* the strings are NOT always aligned properly (ex: received in RADIUS message), so we use the aligned MurmurHash2 function as needed */
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-#define _HASH_MIX(h,k,m) { k *= m; k ^= k >> r; k *= m; h *= m; h ^= k; }
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-uint32_t fd_os_hash ( uint8_t * string, size_t len )
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+/*
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+ * Robert Jenkin's hash function.
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+ * http://burtleburtle.net/bob/hash/evahash.html
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+ * This is in the public domain.
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+ */
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+#define mix(a, b, c) \
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+ do { \
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+ a = a - b; a = a - c; a = a ^ (c >> 13); \
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+ b = b - c; b = b - a; b = b ^ (a << 8); \
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+ c = c - a; c = c - b; c = c ^ (b >> 13); \
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+ a = a - b; a = a - c; a = a ^ (c >> 12); \
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+ b = b - c; b = b - a; b = b ^ (a << 16); \
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+ c = c - a; c = c - b; c = c ^ (b >> 5); \
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+ a = a - b; a = a - c; a = a ^ (c >> 3); \
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+ b = b - c; b = b - a; b = b ^ (a << 10); \
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+ c = c - a; c = c - b; c = c ^ (b >> 15); \
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+ } while (0)
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+
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+unsigned hash_rjenkins(const char *str, unsigned length)
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{
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- uint32_t hash = len;
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- uint8_t * data = string;
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-
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- const unsigned int m = 0x5bd1e995;
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- const int r = 24;
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- int align = (long)string & 3;
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-
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- if (!align || (len < 4)) {
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- /* In case data is aligned, MurmurHash2 function */
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- while(len >= 4)
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- {
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- /* Mix 4 bytes at a time into the hash */
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- uint32_t k = *(uint32_t *)data; /* We don't care about the byte order */
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-
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- _HASH_MIX(hash, k, m);
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-
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- data += 4;
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- len -= 4;
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- }
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-
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- /* Handle the last few bytes of the input */
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- switch(len) {
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- case 3: hash ^= data[2] << 16;
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- case 2: hash ^= data[1] << 8;
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- case 1: hash ^= data[0];
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- hash *= m;
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- }
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-
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- } else {
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- /* Unaligned data, use alignment-safe slower version */
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-
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- /* Pre-load the temp registers */
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- uint32_t t = 0, d = 0;
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- switch(align)
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- {
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- case 1: t |= data[2] << 16;
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- case 2: t |= data[1] << 8;
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- case 3: t |= data[0];
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- }
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- t <<= (8 * align);
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-
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- data += 4-align;
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- len -= 4-align;
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-
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- /* From this point, "data" can be read by chunks of 4 bytes */
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-
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- int sl = 8 * (4-align);
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- int sr = 8 * align;
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-
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- /* Mix */
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- while(len >= 4)
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- {
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- uint32_t k;
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-
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- d = *(unsigned int *)data;
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- k = (t >> sr) | (d << sl);
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-
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- _HASH_MIX(hash, k, m);
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-
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- t = d;
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-
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- data += 4;
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- len -= 4;
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- }
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-
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- /* Handle leftover data in temp registers */
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- d = 0;
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- if(len >= align)
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- {
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- uint32_t k;
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-
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- switch(align)
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- {
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- case 3: d |= data[2] << 16;
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- case 2: d |= data[1] << 8;
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- case 1: d |= data[0];
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- }
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-
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- k = (t >> sr) | (d << sl);
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- _HASH_MIX(hash, k, m);
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-
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- data += align;
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- len -= align;
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-
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- /* Handle tail bytes */
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-
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- switch(len)
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- {
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- case 3: hash ^= data[2] << 16;
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- case 2: hash ^= data[1] << 8;
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- case 1: hash ^= data[0];
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- hash *= m;
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- };
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- }
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- else
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- {
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- switch(len)
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- {
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- case 3: d |= data[2] << 16;
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- case 2: d |= data[1] << 8;
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- case 1: d |= data[0];
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- case 0: hash ^= (t >> sr) | (d << sl);
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- hash *= m;
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- }
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- }
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-
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+ const unsigned char *k = (const unsigned char *)str;
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+ uint32_t a, b, c; /* the internal state */
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+ uint32_t len; /* how many key bytes still need mixing */
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+
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+ /* Set up the internal state */
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+ len = length;
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+ a = 0x9e3779b9; /* the golden ratio; an arbitrary value */
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+ b = a;
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+ c = 0; /* variable initialization of internal state */
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+
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+ /* handle most of the key */
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+ while (len >= 12) {
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+ a = a + (k[0] + ((uint32_t)k[1] << 8) + ((uint32_t)k[2] << 16) +
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+ ((uint32_t)k[3] << 24));
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+ b = b + (k[4] + ((uint32_t)k[5] << 8) + ((uint32_t)k[6] << 16) +
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+ ((uint32_t)k[7] << 24));
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+ c = c + (k[8] + ((uint32_t)k[9] << 8) + ((uint32_t)k[10] << 16) +
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+ ((uint32_t)k[11] << 24));
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+ mix(a, b, c);
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+ k = k + 12;
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+ len = len - 12;
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+ }
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+ /* handle the last 11 bytes */
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+ c = c + length;
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+ switch (len) { /* all the case statements fall through */
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+ case 11:
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+ c = c + ((uint32_t)k[10] << 24);
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+ case 10:
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+ c = c + ((uint32_t)k[9] << 16);
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+ case 9:
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+ c = c + ((uint32_t)k[8] << 8);
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+ /* the first byte of c is reserved for the length */
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+ case 8:
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+ b = b + ((uint32_t)k[7] << 24);
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+ case 7:
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+ b = b + ((uint32_t)k[6] << 16);
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+ case 6:
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+ b = b + ((uint32_t)k[5] << 8);
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+ case 5:
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+ b = b + k[4];
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+ case 4:
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+ a = a + ((uint32_t)k[3] << 24);
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+ case 3:
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+ a = a + ((uint32_t)k[2] << 16);
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+ case 2:
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+ a = a + ((uint32_t)k[1] << 8);
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+ case 1:
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+ a = a + k[0];
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+ /* case 0: nothing left to add */
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}
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+ mix(a, b, c);
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- /* Do a few final mixes of the hash to ensure the last few
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- bytes are well-incorporated. */
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- hash ^= hash >> 13;
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- hash *= m;
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- hash ^= hash >> 15;
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+ return c;
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+}
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- return hash;
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+uint32_t fd_os_hash ( uint8_t * string, size_t len )
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+{
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+ return hash_rjenkins(string, len);
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}
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--
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1.7.10.4
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