jiapengyu
41 lines
1.0 KiB
JavaScript
41 lines
1.0 KiB
JavaScript
import { DeflateRaw } from "zlib";
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import crc32 from "crc-32";
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export default class DeflateCRC32Stream extends DeflateRaw {
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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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this.compressedSize = 0;
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}
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push(chunk, encoding) {
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if (chunk) {
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this.compressedSize += chunk.length;
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}
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return super.push(chunk, encoding);
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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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super._transform(chunk, encoding, callback);
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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(compressed = false) {
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if (compressed) {
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return this.compressedSize;
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} else {
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return this.rawSize;
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}
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}
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}
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