mirror of
https://github.com/arcodange-org/mediabunny.git
synced 2026-09-29 03:43:50 +02:00
Reorder stuff, rename stuff, add license header
This commit is contained in:
Vanilagy
+280
@@ -0,0 +1,280 @@
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/*!
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* Copyright (c) 2025-present, Vanilagy and contributors
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at https://mozilla.org/MPL/2.0/.
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*/
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import { clamp, MaybePromise, toDataView } from './misc';
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import { Source } from './source';
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export class FileSlice {
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bufferPos: number;
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constructor(
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public readonly bytes: Uint8Array,
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public readonly view: DataView,
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private readonly offset: number,
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public readonly start: number,
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public readonly end: number,
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) {
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this.bufferPos = start - offset;
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}
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static tempFromBytes(bytes: Uint8Array) {
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return new FileSlice(
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bytes,
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toDataView(bytes),
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0,
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0,
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bytes.length,
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);
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}
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get length() {
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return this.end - this.start;
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}
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get filePos() {
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return this.offset + this.bufferPos;
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}
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set filePos(value: number) {
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this.bufferPos = value - this.offset;
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}
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skip(byteCount: number) {
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this.bufferPos += byteCount;
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}
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slice(filePos: number, length = this.end - filePos) {
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if (filePos < this.start || filePos + length > this.end) {
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throw new RangeError('Slicing outside of original slice.');
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}
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return new FileSlice(
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this.bytes,
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this.view,
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this.offset,
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filePos,
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filePos + length,
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);
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}
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}
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export class Reader {
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fileSize!: number;
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constructor(public source: Source) {}
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requestSlice(start: number, length: number): MaybePromise<FileSlice | null> {
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if (start + length > this.fileSize) {
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return null;
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}
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const end = start + length;
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const result = this.source._read(start, end);
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if (result instanceof Promise) {
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return result.then((x) => {
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if (!x) {
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return null;
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}
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return new FileSlice(x.bytes, x.view, x.offset, start, end);
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});
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} else {
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if (!result) {
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return null;
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}
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return new FileSlice(result.bytes, result.view, result.offset, start, end);
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}
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}
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requestSliceRange(start: number, minLength: number, maxLength: number): MaybePromise<FileSlice | null> {
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return this.requestSlice(
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start,
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clamp(this.fileSize - start, minLength, maxLength),
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);
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}
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}
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export const readBytes = (slice: FileSlice, length: number) => {
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const bytes = slice.bytes.subarray(slice.bufferPos, slice.bufferPos + length);
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slice.bufferPos += length;
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return bytes;
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};
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export const readU8 = (slice: FileSlice) => slice.view.getUint8(slice.bufferPos++);
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export const readU16 = (slice: FileSlice, littleEndian: boolean) => {
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const value = slice.view.getUint16(slice.bufferPos, littleEndian);
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slice.bufferPos += 2;
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return value;
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};
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export const readU16Be = (slice: FileSlice) => {
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const value = slice.view.getUint16(slice.bufferPos, false);
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slice.bufferPos += 2;
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return value;
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};
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export const readU24Be = (slice: FileSlice) => {
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const high = readU16Be(slice);
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const low = readU8(slice);
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return high * 0x100 + low;
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};
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export const readI16Be = (slice: FileSlice) => {
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const value = slice.view.getInt16(slice.bufferPos, false);
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slice.bufferPos += 2;
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return value;
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};
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export const readU32 = (slice: FileSlice, littleEndian: boolean) => {
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const value = slice.view.getUint32(slice.bufferPos, littleEndian);
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slice.bufferPos += 4;
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return value;
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};
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export const readU32Be = (slice: FileSlice) => {
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const value = slice.view.getUint32(slice.bufferPos, false);
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slice.bufferPos += 4;
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return value;
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};
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export const readU32Le = (slice: FileSlice) => {
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const value = slice.view.getUint32(slice.bufferPos, true);
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slice.bufferPos += 4;
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return value;
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};
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export const readI32Be = (slice: FileSlice) => {
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const value = slice.view.getInt32(slice.bufferPos, false);
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slice.bufferPos += 4;
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return value;
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};
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export const readI32Le = (slice: FileSlice) => {
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const value = slice.view.getInt32(slice.bufferPos, true);
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slice.bufferPos += 4;
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return value;
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};
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export const readU64 = (slice: FileSlice, littleEndian: boolean) => {
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let low: number;
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let high: number;
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if (littleEndian) {
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low = readU32(slice, true);
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high = readU32(slice, true);
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} else {
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high = readU32(slice, false);
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low = readU32(slice, false);
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}
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return high * 0x100000000 + low;
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};
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export const readU64Be = (slice: FileSlice) => {
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const high = readU32Be(slice);
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const low = readU32Be(slice);
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return high * 0x100000000 + low;
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};
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export const readI64Be = (slice: FileSlice) => {
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const high = readI32Be(slice);
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const low = readU32Be(slice);
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return high * 0x100000000 + low;
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};
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export const readI64Le = (slice: FileSlice) => {
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const low = readU32Le(slice);
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const high = readI32Le(slice);
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return high * 0x100000000 + low;
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};
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export const readF32Be = (slice: FileSlice) => {
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const value = slice.view.getFloat32(slice.bufferPos, false);
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slice.bufferPos += 4;
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return value;
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};
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export const readF64Be = (slice: FileSlice) => {
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const value = slice.view.getFloat64(slice.bufferPos, false);
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slice.bufferPos += 8;
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return value;
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};
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export const readAscii = (slice: FileSlice, length: number) => {
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if (slice.bufferPos + length > slice.bytes.length) {
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throw new RangeError('Reading past end of slice.');
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}
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let str = '';
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for (let i = 0; i < length; i++) {
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str += String.fromCharCode(slice.bytes[slice.bufferPos++]!);
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}
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return str;
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};
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export class ReturnValue<T> {
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isPending = true;
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value!: T;
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set(value: T): typeof symbol {
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this.isPending = false;
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this.value = value;
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return symbol;
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}
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}
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const symbol: unique symbol = Symbol();
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export type Uh = Promise<typeof symbol>;
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/*
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class ReturnValue<T> {
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isSet = false;
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value!: T;
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set(value: T) {
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this.isSet = true;
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this.value = value;
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}
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}
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const maybeWait = async (ret: ReturnValue<number>) => {
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if (Math.random() < 0.5) {
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await new Promise(resolve => setTimeout(resolve, 1000));
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}
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ret.set(Math.random());
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};
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const yo = async () => {
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const waitResult = new ReturnValue<number>();
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const promise = maybeWait(waitResult);
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if (!waitResult.isSet) await promise;
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console.log(waitResult.value);
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};
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yo();
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*/
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