add size method to return raw size of data passed-through.

Author: ctalkington

README.md

@@ -44,6 +44,10 @@ Returns the checksum digest in unsigned form.
 
 Returns the hexadecimal representation of the checksum digest. (ie E81722F0)
 
+#### size()
+
+Returns the raw size/length of passed-through data.
+
 ### Instance Options
 
 Inherits [Transform Stream](http://nodejs.org/api/stream.html#stream_class_stream_transform) options.

lib/crc32-stream.js

@@ -14,13 +14,16 @@ 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);
@@ -34,4 +37,8 @@ CRC32Stream.prototype.hex = function() {
   return this.digest().toString(16).toUpperCase();
 };
 
+CRC32Stream.prototype.size = function() {
+  return this.rawSize;
+};
+
 module.exports = CRC32Stream;

test/checksum.js

@@ -16,6 +16,7 @@ describe('CRC32Stream', function() {
     checksum.on('end', function() {
       assert.equal(checksum.digest(), 3893830384);
       assert.equal(checksum.hex(), 'E81722F0');
+      assert.equal(checksum.size(), 16384);
       done();
     });