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27 lines
678 B
27 lines
678 B
import BaseDecoder from './basedecoder.js';
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export default class PackbitsDecoder extends BaseDecoder {
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decodeBlock(buffer) {
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const dataView = new DataView(buffer);
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const out = [];
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for (let i = 0; i < buffer.byteLength; ++i) {
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let header = dataView.getInt8(i);
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if (header < 0) {
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const next = dataView.getUint8(i + 1);
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header = -header;
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for (let j = 0; j <= header; ++j) {
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out.push(next);
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}
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i += 1;
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} else {
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for (let j = 0; j <= header; ++j) {
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out.push(dataView.getUint8(i + j + 1));
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}
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i += header + 1;
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}
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}
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return new Uint8Array(out).buffer;
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}
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}
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