From 9305f4e11b085eb5fe82fd706bb93c556ff50ae3 Mon Sep 17 00:00:00 2001
From: codedread <codedread@gmail.com>
Date: Sun, 19 Feb 2017 09:22:47 -0800
Subject: [PATCH] Add factory method to archive.js that returns an
 Unrarrer/Unzipper/Untarrer

---
 archive.js | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/archive.js b/archive.js
index 1596b74..bc2ab78 100644
--- a/archive.js
+++ b/archive.js
@@ -350,4 +350,25 @@ bitjs.archive.Untarrer = function(arrayBuffer, opt_pathToBitJS) {
 bitjs.inherits(bitjs.archive.Untarrer, bitjs.archive.Unarchiver);
 bitjs.archive.Untarrer.prototype.getScriptFileName = function() { return 'untar.js' };
 
+/**
+ * Factory method that creates an unarchiver based on the byte signature found
+ * in the arrayBuffer.
+ * @param {ArrayBuffer} ab
+ * @param {string=} opt_pathToBitJS Path to the unarchiver script files.
+ * @return {bitjs.archive.Unarchiver}
+ */
+bitjs.archive.GetUnarchiver = function(ab, opt_pathToBitJS) {
+  var unarchiver = null;
+  var pathToBitJS = opt_pathToBitJS || '';
+  var h = new Uint8Array(ab, 0, 10);
+  if (h[0] == 0x52 && h[1] == 0x61 && h[2] == 0x72 && h[3] == 0x21) { //Rar!
+    unarchiver = new bitjs.archive.Unrarrer(ab, pathToBitJS);
+  } else if (h[0] == 80 && h[1] == 75) { // PK (Zip)
+    unarchiver = new bitjs.archive.Unzipper(ab, pathToBitJS);
+  } else { // Try with tar
+    unarchiver = new bitjs.archive.Untarrer(ab, pathToBitJS);
+  }
+  return unarchiver;
+};
+
 })();
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