jiapengyu
30 lines
756 B
JavaScript
30 lines
756 B
JavaScript
import { Transform } from "readable-stream";
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import crc32 from "crc-32";
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export default class CRC32Stream extends Transform {
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constructor(options) {
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super(options);
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this.checksum = Buffer.allocUnsafe(4);
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this.checksum.writeInt32BE(0, 0);
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this.rawSize = 0;
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}
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_transform(chunk, encoding, callback) {
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if (chunk) {
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this.checksum = crc32.buf(chunk, this.checksum) >>> 0;
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this.rawSize += chunk.length;
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}
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callback(null, chunk);
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}
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digest(encoding) {
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const checksum = Buffer.allocUnsafe(4);
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checksum.writeUInt32BE(this.checksum >>> 0, 0);
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return encoding ? checksum.toString(encoding) : checksum;
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}
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hex() {
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return this.digest("hex").toUpperCase();
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}
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size() {
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return this.rawSize;
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}
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}
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