deflate-crc32-stream.js•1.29 kB
/**
* 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 {DeflateRaw} = require('zlib');
const crc32 = require('crc-32');
class DeflateCRC32Stream extends DeflateRaw {
constructor(options) {
super(options);
this.checksum = Buffer.allocUnsafe(4);
this.checksum.writeInt32BE(0, 0);
this.rawSize = 0;
this.compressedSize = 0;
}
push(chunk, encoding) {
if (chunk) {
this.compressedSize += chunk.length;
}
return super.push(chunk, encoding);
}
_transform(chunk, encoding, callback) {
if (chunk) {
this.checksum = crc32.buf(chunk, this.checksum) >>> 0;
this.rawSize += chunk.length;
}
super._transform(chunk, encoding, callback)
}
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(compressed = false) {
if (compressed) {
return this.compressedSize;
} else {
return this.rawSize;
}
}
}
module.exports = DeflateCRC32Stream;