96 lines
2.8 KiB
TypeScript
96 lines
2.8 KiB
TypeScript
import { Queue, Stack } from 'mnemonist';
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import { EbmlTagTrait } from './models/tag-trait';
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import { EbmlTagPosition } from './models/enums';
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import { EbmlMasterTag } from './models/tag-master';
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import { EbmlTreeMasterNotMatchError, UnreachableOrLogicError } from './errors';
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import type { EbmlTagType } from './models/tag';
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export class EbmlEncodeStreamTransformer
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implements Transformer<EbmlTagTrait | EbmlTagType, Uint8Array>
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{
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stack = new Stack<[EbmlMasterTag, Uint8Array[]]>();
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_writeBuffer = new Queue<Uint8Array>();
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_writeBufferTask: Promise<void> | undefined;
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closed = false;
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tryEnqueueToBuffer(...frag: Uint8Array[]) {
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const top = this.stack.peek();
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if (top) {
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top[1].push(...frag);
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} else {
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for (const f of frag) {
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this._writeBuffer.enqueue(f);
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}
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}
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}
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waitBufferRelease(
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ctrl: TransformStreamDefaultController<Uint8Array>,
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isFlush: boolean
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) {
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while (this._writeBuffer.size) {
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if (ctrl.desiredSize! <= 0 && !isFlush) {
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break;
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}
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const pop = this._writeBuffer.dequeue();
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ctrl.enqueue(pop);
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}
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}
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// biome-ignore lint/complexity/noExcessiveCognitiveComplexity: <explanation>
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async transform(
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tag: EbmlTagTrait | EbmlTagType,
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ctrl: TransformStreamDefaultController<Uint8Array>
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) {
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if (!(tag instanceof EbmlTagTrait)) {
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throw new UnreachableOrLogicError('should only accept embl tag but not');
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}
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if (tag instanceof EbmlMasterTag) {
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if (tag.contentLength === Number.POSITIVE_INFINITY) {
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if (tag.position === EbmlTagPosition.Start) {
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this.tryEnqueueToBuffer(...tag.encodeHeader());
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}
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} else {
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// biome-ignore lint/style/useCollapsedElseIf: <explanation>
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if (tag.position === EbmlTagPosition.Start) {
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this.stack.push([tag, []]);
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} else {
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const pop = this.stack.pop();
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if (!pop) {
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throw new EbmlTreeMasterNotMatchError(tag);
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}
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const [startTag, fragments] = pop;
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const size = fragments.reduce(
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(acc, curr) => acc + curr.byteLength,
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0
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);
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startTag.contentLength = size;
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this.tryEnqueueToBuffer(...startTag.encodeHeader());
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this.tryEnqueueToBuffer(...fragments);
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}
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}
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} else {
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this.tryEnqueueToBuffer(...tag.encode());
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}
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this.waitBufferRelease(ctrl, false);
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}
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flush(ctrl: TransformStreamDefaultController<Uint8Array>) {
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this.waitBufferRelease(ctrl, true);
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}
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}
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export class EbmlStreamEncoder extends TransformStream<
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EbmlTagTrait | EbmlTagType,
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Uint8Array
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> {
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public readonly transformer: EbmlEncodeStreamTransformer;
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constructor() {
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const transformer = new EbmlEncodeStreamTransformer();
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super(transformer);
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this.transformer = transformer;
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}
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}
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