use 137 as seed2 to reduce hash collisions, fixes #16

zenozeng · Mar 2, 2015 · 7f0bb7a · 7f0bb7a
1 parent 155ef10
commit 7f0bb7a
Show file tree

Hide file tree

Showing 4 changed files with 10 additions and 6 deletions.
diff --git a/bower.json b/bower.json
@@ -1,6 +1,6 @@
 {
   "name": "color-hash",
-  "version": "1.0.0",
+  "version": "1.0.1",
   "homepage": "https://github.com/zenozeng/color-hash",
   "authors": [
     "Zeno Zeng <[email protected]>"

diff --git a/dist/color-hash.js b/dist/color-hash.js
@@ -7,11 +7,13 @@
  */
 var BKDRHash = function(str) {
     var seed = 131;
+    var seed2 = 137;
     var hash = 0;
-    var MAX_SAFE_INTEGER = parseInt(9007199254740991 / seed / seed); // Number.MAX_SAFE_INTEGER equals  9007199254740991
+    // Note: Number.MAX_SAFE_INTEGER equals 9007199254740991
+    var MAX_SAFE_INTEGER = parseInt(9007199254740991 / seed2);
     for(var i = 0; i < str.length; i++) {
         if(hash > MAX_SAFE_INTEGER) {
-            hash = parseInt(hash / seed);
+            hash = parseInt(hash / seed2);
         }
         hash = hash * seed + str.charCodeAt(i);
     }

diff --git a/lib/bkdr-hash.js b/lib/bkdr-hash.js
@@ -6,11 +6,13 @@
  */
 var BKDRHash = function(str) {
     var seed = 131;
+    var seed2 = 137;
     var hash = 0;
-    var MAX_SAFE_INTEGER = parseInt(9007199254740991 / seed / seed); // Number.MAX_SAFE_INTEGER equals  9007199254740991
+    // Note: Number.MAX_SAFE_INTEGER equals 9007199254740991
+    var MAX_SAFE_INTEGER = parseInt(9007199254740991 / seed2);
     for(var i = 0; i < str.length; i++) {
         if(hash > MAX_SAFE_INTEGER) {
-            hash = parseInt(hash / seed);
+            hash = parseInt(hash / seed2);
         }
         hash = hash * seed + str.charCodeAt(i);
     }

diff --git a/package.json b/package.json
@@ -1,6 +1,6 @@
 {
     "name": "color-hash",
-    "version": "1.0.0",
+    "version": "1.0.1",
     "description": "Generate color based on the given string (using HSL color space and BKDRHash).",
     "main": "lib/color-hash.js",
     "scripts": {