Current Dev State

static/js/ketcher2/node_modules/crc32-stream/lib/crc32-stream.js

@@ -0,0 +1,44 @@
+/**
+ * node-crc32-stream
+ *
+ * Copyright (c) 2014 Chris Talkington, contributors.
+ * Licensed under the MIT license.
+ * https://github.com/archiverjs/node-crc32-stream/blob/master/LICENSE-MIT
+ */
+var inherits = require('util').inherits;
+var Transform = require('readable-stream').Transform;
+
+var crc32 = require('crc').crc32;
+
+var CRC32Stream = module.exports = function CRC32Stream(options) {
+  Transform.call(this, options);
+  this.checksum = new Buffer(4);
+  this.checksum.writeInt32BE(0, 0);
+
+  this.rawSize = 0;
+};
+
+inherits(CRC32Stream, Transform);
+
+CRC32Stream.prototype._transform = function(chunk, encoding, callback) {
+  if (chunk) {
+    this.checksum = crc32(chunk, this.checksum);
+    this.rawSize += chunk.length;
+  }
+
+  callback(null, chunk);
+};
+
+CRC32Stream.prototype.digest = function(encoding) {
+  var checksum = new Buffer(4);
+  checksum.writeUInt32BE(this.checksum >>> 0, 0);
+  return encoding ? checksum.toString(encoding) : checksum;
+};
+
+CRC32Stream.prototype.hex = function() {
+  return this.digest('hex').toUpperCase();
+};
+
+CRC32Stream.prototype.size = function() {
+  return this.rawSize;
+};