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-rw-r--r--libs/lmo/src/lmo_hash.c53
1 files changed, 53 insertions, 0 deletions
diff --git a/libs/lmo/src/lmo_hash.c b/libs/lmo/src/lmo_hash.c
new file mode 100644
index 000000000..bc8e6fe4e
--- /dev/null
+++ b/libs/lmo/src/lmo_hash.c
@@ -0,0 +1,53 @@
+/*
+ * Hash function from http://www.azillionmonkeys.com/qed/hash.html
+ * Copyright (C) 2004-2008 by Paul Hsieh
+ */
+
+#include "lmo.h"
+
+uint32_t sfh_hash(const char * data, int len)
+{
+ uint32_t hash = len, tmp;
+ int rem;
+
+ if (len <= 0 || data == NULL) return 0;
+
+ rem = len & 3;
+ len >>= 2;
+
+ /* Main loop */
+ for (;len > 0; len--) {
+ hash += sfh_get16(data);
+ tmp = (sfh_get16(data+2) << 11) ^ hash;
+ hash = (hash << 16) ^ tmp;
+ data += 2*sizeof(uint16_t);
+ hash += hash >> 11;
+ }
+
+ /* Handle end cases */
+ switch (rem) {
+ case 3: hash += sfh_get16(data);
+ hash ^= hash << 16;
+ hash ^= data[sizeof(uint16_t)] << 18;
+ hash += hash >> 11;
+ break;
+ case 2: hash += sfh_get16(data);
+ hash ^= hash << 11;
+ hash += hash >> 17;
+ break;
+ case 1: hash += *data;
+ hash ^= hash << 10;
+ hash += hash >> 1;
+ }
+
+ /* Force "avalanching" of final 127 bits */
+ hash ^= hash << 3;
+ hash += hash >> 5;
+ hash ^= hash << 4;
+ hash += hash >> 17;
+ hash ^= hash << 25;
+ hash += hash >> 6;
+
+ return hash;
+}
+