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mc_test/node_modules/crc32-stream/lib/crc32-stream.js

@@ -0,0 +1,48 @@
+/**
+ * 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
+ */
+
+ 'use strict';
+
+const {Transform} = require('readable-stream');
+
+const crc32 = require('crc-32');
+
+class CRC32Stream extends Transform {
+  constructor(options) {
+    super(options);
+    this.checksum = Buffer.allocUnsafe(4);
+    this.checksum.writeInt32BE(0, 0);
+
+    this.rawSize = 0;
+  }
+
+  _transform(chunk, encoding, callback) {
+    if (chunk) {
+      this.checksum = crc32.buf(chunk, this.checksum) >>> 0;
+      this.rawSize += chunk.length;
+    }
+
+    callback(null, chunk);
+  }
+
+  digest(encoding) {
+    const checksum = Buffer.allocUnsafe(4);
+    checksum.writeUInt32BE(this.checksum >>> 0, 0);
+    return encoding ? checksum.toString(encoding) : checksum;
+  }
+
+  hex() {
+    return this.digest('hex').toUpperCase();
+  }
+
+  size() {
+    return this.rawSize;
+  }
+}
+
+module.exports = CRC32Stream;