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import { Buffer } from "./deps.ts";
/** * This stream transform will buffer the data it receives until it has enough to form * a chunk of the specified size, then pass on the data in chunks of the specified size. */export class TransformChunkSizes extends TransformStream<Uint8Array, Uint8Array> {  constructor(outChunkSize: number) {    // This large buffer holds all the incoming data we receive until we reach at least outChunkSize, which we then pass on.    const buffer = new Buffer();    buffer.grow(outChunkSize);
    super({      start() {}, // required      async transform(chunk, controller) {        buffer.write(chunk);
        while (buffer.length >= outChunkSize) {          const outChunk = new Uint8Array(outChunkSize);          const readFromBuffer = await buffer.read(outChunk);          if (readFromBuffer !== outChunkSize) {            throw new Error(              `Unexpectedly read ${readFromBuffer} bytes from transform buffer when trying to read ${outChunkSize} bytes.`,            );          }          // Now "outChunk" holds the next chunk of data - pass it on to the output:          controller.enqueue(outChunk);        }      },      flush(controller) {        if (buffer.length) {          // The buffer still contains some data, send it now even though it's smaller than the desired chunk size.          controller.enqueue(buffer.bytes());        }      },    });  }}