From c447a5da8c8087d94867560764b59f03d0e70b1d Mon Sep 17 00:00:00 2001
From: Simon Howard
Date: Sat, 16 Jun 2007 16:02:46 +0000
Subject: Switch to djb2 hash function and shut up compiler warnings

Subversion-branch: /trunk/chocolate-doom
Subversion-revision: 908
---
 src/w_wad.c | 28 ++++++++++++----------------
 1 file changed, 12 insertions(+), 16 deletions(-)

diff --git a/src/w_wad.c b/src/w_wad.c
index 892086d7..598794c4 100644
--- a/src/w_wad.c
+++ b/src/w_wad.c
@@ -98,25 +98,21 @@ static void ExtractFileBase(char *path, char *dest)
 }
 
 // Hash function used for lump names.
-// Must be mod'ed with table size.
-// Can be used for any 8-character names.
-// by Lee Killough
 
 unsigned int W_LumpNameHash(const char *s)
 {
-  unsigned int hash;
-
-  ((hash =        toupper(s[0]), s[1]) &&
-   (hash = hash*3+toupper(s[1]), s[2]) &&
-   (hash = hash*2+toupper(s[2]), s[3]) &&
-   (hash = hash*2+toupper(s[3]), s[4]) &&
-   (hash = hash*2+toupper(s[4]), s[5]) &&
-   (hash = hash*2+toupper(s[5]), s[6]) &&
-   (hash = hash*2+toupper(s[6]),
-    hash = hash*2+toupper(s[7]))
-  );
-
-  return hash;
+    // This is the djb2 string hash function, modded to work on strings
+    // that have a maximum length of 8.
+
+    unsigned int result = 5381;
+    unsigned int i;
+
+    for (i=0; i < 8 && s[i] != '\0'; ++i)
+    {
+        result = ((result << 5) ^ result ) ^ toupper(s[i]);
+    }
+
+    return result;
 }
 
 //
-- 
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