1 files changed, 85 insertions, 0 deletions
diff --git a/lib/hash.c b/lib/hash.c
new file mode 100644
index 000000000..af8f21bb1
--- /dev/null
+++ b/lib/hash.c
@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2008, 2009 Nicira Networks.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+#include <config.h>
+#include "hash.h"
+#include <string.h>
+
+/* Returns the hash of the 'n' 32-bit words at 'p', starting from 'basis'.
+ * 'p' must be properly aligned. */
+uint32_t
+hash_words(const uint32_t *p, size_t n, uint32_t basis)
+{
+    uint32_t a, b, c;
+
+    a = b = c = 0xdeadbeef + (((uint32_t) n) << 2) + basis;
+
+    while (n > 3) {
+        a += p[0];
+        b += p[1];
+        c += p[2];
+        HASH_MIX(a, b, c);
+        n -= 3;
+        p += 3;
+    }
+
+    switch (n) {
+    case 3:
+        c += p[2];
+        /* fall through */
+    case 2:
+        b += p[1];
+        /* fall through */
+    case 1:
+        a += p[0];
+        HASH_FINAL(a, b, c);
+        /* fall through */
+    case 0:
+        break;
+    }
+    return c;
+}
+
+/* Returns the hash of the 'n' bytes at 'p', starting from 'basis'. */
+uint32_t
+hash_bytes(const void *p_, size_t n, uint32_t basis)
+{
+    const uint8_t *p = p_;
+    uint32_t a, b, c;
+    uint32_t tmp[3];
+
+    a = b = c = 0xdeadbeef + n + basis;
+
+    while (n >= sizeof tmp) {
+        memcpy(tmp, p, sizeof tmp);
+        a += tmp[0];
+        b += tmp[1];
+        c += tmp[2];
+        HASH_MIX(a, b, c);
+        n -= sizeof tmp;
+        p += sizeof tmp;
+    }
+
+    if (n) {
+        tmp[0] = tmp[1] = tmp[2] = 0;
+        memcpy(tmp, p, n);
+        a += tmp[0];
+        b += tmp[1];
+        c += tmp[2];
+        HASH_FINAL(a, b, c);
+    }
+
+    return c;
+}