publishing v1 of action

node_modules/unzipper/lib/Decrypt.js

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+var bigInt = require('big-integer');
+var Stream = require('stream');
+
+// Backwards compatibility for node versions < 8
+if (!Stream.Writable || !Stream.Writable.prototype.destroy)
+  Stream = require('readable-stream');
+
+var table;
+
+function generateTable() {
+  var poly = 0xEDB88320,c,n,k;
+  table = [];
+  for (n = 0; n < 256; n++) {
+    c = n;
+    for (k = 0; k < 8; k++)
+      c = (c & 1) ? poly ^ (c >>> 1) :  c = c >>> 1;
+    table[n] = c >>> 0;
+  }
+}
+
+function crc(ch,crc) {
+  if (!table)
+    generateTable();
+
+  if (ch.charCodeAt)
+    ch = ch.charCodeAt(0);        
+
+  return (bigInt(crc).shiftRight(8).and(0xffffff)).xor(table[bigInt(crc).xor(ch).and(0xff)]).value;
+}
+
+function Decrypt() {
+  if (!(this instanceof Decrypt))
+    return new Decrypt();
+
+  this.key0 = 305419896;
+  this.key1 = 591751049;
+  this.key2 = 878082192;
+}
+
+Decrypt.prototype.update = function(h) {            
+  this.key0 = crc(h,this.key0);
+  this.key1 = bigInt(this.key0).and(255).and(4294967295).add(this.key1)
+  this.key1 = bigInt(this.key1).multiply(134775813).add(1).and(4294967295).value;
+  this.key2 = crc(bigInt(this.key1).shiftRight(24).and(255), this.key2);
+}
+
+
+Decrypt.prototype.decryptByte = function(c) {
+  var k = bigInt(this.key2).or(2);
+  c = c ^ bigInt(k).multiply(bigInt(k^1)).shiftRight(8).and(255);
+  this.update(c);
+  return c;
+};
+
+ Decrypt.prototype.stream = function() {
+  var stream = Stream.Transform(),
+      self = this;
+
+  stream._transform = function(d,e,cb) {
+    for (var i = 0; i<d.length;i++) {
+      d[i] = self.decryptByte(d[i]);
+    }
+    this.push(d);
+    cb();
+  };
+  return stream;
+};
+
+
+
+
+module.exports = Decrypt;