From: Florian Festi <ffesti@redhat.com>
Date: Thu, 16 Oct 2008 07:59:54 +0000 (+0200)
Subject: Switch to a better hash functions for strings: Jenkins One-at-a-time hash
X-Git-Tag: rpm-4.7.0-beta1~398
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=ecc8ff93740f1cc733350016b9b4304c4f14e9d6;p=platform%2Fupstream%2Frpm.git

Switch to a better hash functions for strings: Jenkins One-at-a-time hash
---

diff --git a/lib/rpmhash.c b/lib/rpmhash.c
index 5d5d6a7..34be313 100644
--- a/lib/rpmhash.c
+++ b/lib/rpmhash.c
@@ -5,19 +5,20 @@
 
 #include "lib/rpmhash.h"
 
-unsigned int hashFunctionString(const char * string)
-{
-    char xorValue = 0;
-    char sum = 0;
-    short len;
-    int i;
-    const char * chp = string;
 
-    len = strlen(string);
-    for (i = 0; i < len; i++, chp++) {
-	xorValue ^= *chp;
-	sum += *chp;
-    }
+unsigned int hashFunctionString(const char * string) {
+    /* Jenkins One-at-a-time hash */
+
+    unsigned int hash = 0xe4721b68;
 
-    return ((((unsigned)len) << 16) + (((unsigned)sum) << 8) + xorValue);
+    while (*string != '\0') {
+      hash += *string;
+      hash += (hash << 10);
+      hash ^= (hash >> 6);
+      string++;
+    }
+    hash += (hash << 3);
+    hash ^= (hash >> 11);
+    hash += (hash << 15);
+    return hash;
 }