42 lines
1.1 KiB
JavaScript
42 lines
1.1 KiB
JavaScript
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const streams = require('web-streams-polyfill');
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class BlobSlicer {
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constructor(blob, size, decrypt) {
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this.blob = blob;
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this.size = size;
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this.index = 0;
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this.decrypt = decrypt;
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}
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pull(controller) {
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return new Promise((resolve, reject) => {
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const bytesLeft = this.blob.size - this.index;
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if (bytesLeft <= 0) {
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controller.close();
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return resolve();
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}
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let size = 0;
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if (this.decrypt && this.index === 0) {
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size = Math.min(21, bytesLeft);
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} else {
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size = Math.min(this.size, bytesLeft);
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}
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const blob = this.blob.slice(this.index, this.index + size);
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const reader = new FileReader();
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reader.onload = function() {
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controller.enqueue(new Uint8Array(this.result));
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resolve();
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};
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reader.onerror = reject;
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reader.readAsArrayBuffer(blob);
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this.index += size;
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});
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}
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}
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export default class BlobSliceStream extends streams.ReadableStream {
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constructor(blob, size, decrypt) {
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super(new BlobSlicer(blob, size, decrypt));
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}
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}
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