Updated hashing function. Updated readme file

bottiger · Jun 21, 2024 · 9794052 · 9794052
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diff --git a/README.md b/README.md
@@ -1,4 +1,4 @@
-# Trolling with Love Firefox Extension
+# Trolling with Love ❤️ Firefox Extension
 
 **Trolling with Love** is a Firefox extension designed for mischief and humor among friends. It replaces a small percentage of images on web pages with images of Nicolas Cage or ponies, based on user settings. This playful tool allows you to surprise and amuse your friends as they browse the web.
 
@@ -13,12 +13,8 @@
 
 ## Installation
 
-To install the extension, follow these steps:
-
-1. Download the extension package (`trolling-with-love.xpi`).
-2. Open Firefox and navigate to `about:addons`.
-3. Click on the gear icon and select "Install Add-on From File".
-4. Choose the downloaded `trolling-with-love.xpi` file and click "Install".
+Get the latest version here: https://addons.mozilla.org/en-US/firefox/addon/trolling-with-love/
+Be nice and write you name in the settings for the extension in order to identify yourself ❤️
 
 ## Usage
 

diff --git a/src/optimize.js b/src/optimize.js
@@ -27,6 +27,67 @@ var totalImages = images.length;
 
 var replacementImages = [];
 
+function fnv1a(str) {
+    let hash = 0x811c9dc5;
+    for (let i = 0; i < str.length; i++) {
+        hash ^= str.charCodeAt(i);
+        hash = (hash * 0x01000193) >>> 0;
+    }
+    return hash >>> 0;
+}
+
+function murmurhash3_32_gc(key, seed) {
+    let remainder, bytes, h1, h1b, c1, c2, k1, i;
+
+    remainder = key.length & 3; // key.length % 4
+    bytes = key.length - remainder;
+    h1 = seed;
+    c1 = 0xcc9e2d51;
+    c2 = 0x1b873593;
+    i = 0;
+
+    while (i < bytes) {
+        k1 = 
+          ((key.charCodeAt(i) & 0xff)) |
+          ((key.charCodeAt(++i) & 0xff) << 8) |
+          ((key.charCodeAt(++i) & 0xff) << 16) |
+          ((key.charCodeAt(++i) & 0xff) << 24);
+        ++i;
+
+        k1 = (((k1 & 0xffff) * c1) + ((((k1 >>> 16) * c1) & 0xffff) << 16)) & 0xffffffff;
+        k1 = (k1 << 15) | (k1 >>> 17);
+        k1 = (((k1 & 0xffff) * c2) + ((((k1 >>> 16) * c2) & 0xffff) << 16)) & 0xffffffff;
+
+        h1 ^= k1;
+        h1 = (h1 << 13) | (h1 >>> 19);
+        h1b = (((h1 & 0xffff) * 5) + ((((h1 >>> 16) * 5) & 0xffff) << 16)) & 0xffffffff;
+        h1 = (((h1b & 0xffff) + 0x6b64) + ((((h1b >>> 16) + 0xe654) & 0xffff) << 16));
+    }
+
+    k1 = 0;
+
+    switch (remainder) {
+        case 3: k1 ^= (key.charCodeAt(i + 2) & 0xff) << 16;
+        case 2: k1 ^= (key.charCodeAt(i + 1) & 0xff) << 8;
+        case 1: k1 ^= (key.charCodeAt(i) & 0xff);
+
+        k1 = (((k1 & 0xffff) * c1) + ((((k1 >>> 16) * c1) & 0xffff) << 16)) & 0xffffffff;
+        k1 = (k1 << 15) | (k1 >>> 17);
+        k1 = (((k1 & 0xffff) * c2) + ((((k1 >>> 16) * c2) & 0xffff) << 16)) & 0xffffffff;
+        h1 ^= k1;
+    }
+
+    h1 ^= key.length;
+
+    h1 ^= h1 >>> 16;
+    h1 = (((h1 & 0xffff) * 0x85ebca6b) + ((((h1 >>> 16) * 0x85ebca6b) & 0xffff) << 16)) & 0xffffffff;
+    h1 ^= h1 >>> 13;
+    h1 = (((h1 & 0xffff) * 0xc2b2ae35) + ((((h1 >>> 16) * 0xc2b2ae35) & 0xffff) << 16)) & 0xffffffff;
+    h1 ^= h1 >>> 16;
+
+    return h1 >>> 0;
+}
+
 // DJB2 hash function
 function djb2Hash(str) {
     let hash = 5381;
@@ -42,9 +103,8 @@ function scaleHashToNumber(hash) {
 }
 
 // Function to pick a random element from the array using imgHashVal
-function pickRandomElement(replacement_urls, imgHashVal) {
-    const index = Math.floor(imgHashVal * replacement_urls.length);
-    return replacement_urls[index];
+function pickRandomElement(replacement_urls, imgIndex) {
+    return replacement_urls[imgIndex];
 }
 
 
@@ -62,7 +122,7 @@ function isNumber(value) {
 
 function replaceImage(image_url, replacement_urls) {
 
-    var imgHashVal = scaleHashToNumber(djb2Hash(image_url));
+    var imgHashVal = scaleHashToNumber(murmurhash3_32_gc(image_url, 0x12399678));
 
     if (isDebug)
         console.log(imgHashVal + ': ' + image_url);
@@ -77,7 +137,11 @@ function replaceImage(image_url, replacement_urls) {
         return image_url;
     }
 
-    var newImageIdx = cachedTotalProbability > 0 ? imgHashVal / cachedTotalProbability : 0;
+    var newImageIdx = cachedTotalProbability > 0 ? (imgHashVal / cachedTotalProbability) * replacement_urls.length : 0;
+    newImageIdx = Math.floor(newImageIdx);
+
+    console.log("imgHashVal" + imgHashVal + " scaled: " + (imgHashVal / cachedTotalProbability) +  " New image idx: " + newImageIdx + " cachedTotalProbability: " + cachedTotalProbability);
+
     return pickRandomElement(replacement_urls, newImageIdx);
 }