54 lines
1.8 KiB
JavaScript
54 lines
1.8 KiB
JavaScript
import { EndOfStreamError } from './stream/index.js';
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import { AbstractTokenizer } from './AbstractTokenizer.js';
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export class BlobTokenizer extends AbstractTokenizer {
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/**
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* Construct BufferTokenizer
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* @param blob - Uint8Array to tokenize
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* @param options Tokenizer options
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*/
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constructor(blob, options) {
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super(options);
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this.blob = blob;
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this.fileInfo = { ...options?.fileInfo ?? {}, ...{ size: blob.size, mimeType: blob.type } };
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}
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/**
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* Read buffer from tokenizer
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* @param uint8Array - Uint8Array to tokenize
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* @param options - Read behaviour options
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* @returns {Promise<number>}
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*/
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async readBuffer(uint8Array, options) {
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if (options?.position) {
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this.position = options.position;
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}
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const bytesRead = await this.peekBuffer(uint8Array, options);
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this.position += bytesRead;
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return bytesRead;
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}
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/**
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* Peek (read ahead) buffer from tokenizer
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* @param buffer
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* @param options - Read behaviour options
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* @returns {Promise<number>}
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*/
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async peekBuffer(buffer, options) {
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const normOptions = this.normalizeOptions(buffer, options);
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const bytes2read = Math.min(this.blob.size - normOptions.position, normOptions.length);
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if ((!normOptions.mayBeLess) && bytes2read < normOptions.length) {
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throw new EndOfStreamError();
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}
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const arrayBuffer = await this.blob.slice(normOptions.position, normOptions.position + bytes2read).arrayBuffer();
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buffer.set(new Uint8Array(arrayBuffer));
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return bytes2read;
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}
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close() {
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return super.close();
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}
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supportsRandomAccess() {
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return true;
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}
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setPosition(position) {
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this.position = position;
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}
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}
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