Current Dev State

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

@@ -0,0 +1,69 @@
+/**
+ * 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 zlib = require('zlib');
+var inherits = require('util').inherits;
+
+var crc32 = require('crc').crc32;
+
+var DeflateCRC32Stream = module.exports = function (options) {
+  zlib.DeflateRaw.call(this, options);
+
+  this.checksum = new Buffer(4);
+  this.checksum.writeInt32BE(0, 0);
+
+  this.rawSize = 0;
+  this.compressedSize = 0;
+
+  // BC v0.8
+  if (typeof zlib.DeflateRaw.prototype.push !== 'function') {
+    this.on('data', function(chunk) {
+      if (chunk) {
+        this.compressedSize += chunk.length;
+      }
+    });
+  }
+};
+
+inherits(DeflateCRC32Stream, zlib.DeflateRaw);
+
+DeflateCRC32Stream.prototype.push = function(chunk, encoding) {
+  if (chunk) {
+    this.compressedSize += chunk.length;
+  }
+
+  return zlib.DeflateRaw.prototype.push.call(this, chunk, encoding);
+};
+
+DeflateCRC32Stream.prototype.write = function(chunk, enc, cb) {
+  if (chunk) {
+    this.checksum = crc32(chunk, this.checksum);
+    this.rawSize += chunk.length;
+  }
+
+  return zlib.DeflateRaw.prototype.write.call(this, chunk, enc, cb);
+};
+
+DeflateCRC32Stream.prototype.digest = function(encoding) {
+  var checksum = new Buffer(4);
+  checksum.writeUInt32BE(this.checksum >>> 0, 0);
+  return encoding ? checksum.toString(encoding) : checksum;
+};
+
+DeflateCRC32Stream.prototype.hex = function() {
+  return this.digest('hex').toUpperCase();
+};
+
+DeflateCRC32Stream.prototype.size = function(compressed) {
+  compressed = compressed || false;
+
+  if (compressed) {
+    return this.compressedSize;
+  } else {
+    return this.rawSize;
+  }
+};