1 files changed, 52 insertions, 0 deletions
diff --git a/toolkit/components/resistfingerprinting/tests/browser/head.js b/toolkit/components/resistfingerprinting/tests/browser/head.js
new file mode 100644
index 0000000000..a5a0b7ef55
--- /dev/null
+++ b/toolkit/components/resistfingerprinting/tests/browser/head.js
@@ -0,0 +1,52 @@
+// Number of bits in the canvas that we randomize when canvas randomization is
+// enabled.
+const NUM_RANDOMIZED_CANVAS_BITS = 256;
+
+/**
+ * Compares two Uint8Arrays and returns the number of bits that are different.
+ *
+ * @param {Uint8ClampedArray} arr1 - The first Uint8ClampedArray to compare.
+ * @param {Uint8ClampedArray} arr2 - The second Uint8ClampedArray to compare.
+ * @returns {number} - The number of bits that are different between the two
+ *                     arrays.
+ */
+function compareUint8Arrays(arr1, arr2) {
+  let count = 0;
+  for (let i = 0; i < arr1.length; i++) {
+    let diff = arr1[i] ^ arr2[i];
+    while (diff > 0) {
+      count += diff & 1;
+      diff >>= 1;
+    }
+  }
+  return count;
+}
+
+/**
+ * Compares two ArrayBuffer objects to see if they are different.
+ *
+ * @param {ArrayBuffer} buffer1 - The first buffer to compare.
+ * @param {ArrayBuffer} buffer2 - The second buffer to compare.
+ * @returns {boolean} True if the buffers are different, false if they are the
+ *                    same.
+ */
+function compareArrayBuffer(buffer1, buffer2) {
+  // compare the byte lengths of the two buffers
+  if (buffer1.byteLength !== buffer2.byteLength) {
+    return true;
+  }
+
+  // create typed arrays to represent the two buffers
+  const view1 = new DataView(buffer1);
+  const view2 = new DataView(buffer2);
+
+  // compare the byte values of the two typed arrays
+  for (let i = 0; i < buffer1.byteLength; i++) {
+    if (view1.getUint8(i) !== view2.getUint8(i)) {
+      return true;
+    }
+  }
+
+  // the two buffers are the same
+  return false;
+}