51 lines
1.9 KiB
JavaScript
51 lines
1.9 KiB
JavaScript
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import { AbstractTokenizer } from './AbstractTokenizer.js';
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import { EndOfStreamError } from 'peek-readable';
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import * as fs from './FsPromise.js';
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export class FileTokenizer extends AbstractTokenizer {
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constructor(fd, fileInfo) {
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super(fileInfo);
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this.fd = fd;
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}
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/**
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* Read buffer from file
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* @param uint8Array - Uint8Array to write result to
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* @param options - Read behaviour options
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* @returns Promise number of bytes read
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*/
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async readBuffer(uint8Array, options) {
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const normOptions = this.normalizeOptions(uint8Array, options);
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this.position = normOptions.position;
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const res = await fs.read(this.fd, uint8Array, normOptions.offset, normOptions.length, normOptions.position);
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this.position += res.bytesRead;
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if (res.bytesRead < normOptions.length && (!options || !options.mayBeLess)) {
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throw new EndOfStreamError();
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}
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return res.bytesRead;
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}
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/**
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* Peek buffer from file
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* @param uint8Array - Uint8Array (or Buffer) to write data to
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* @param options - Read behaviour options
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* @returns Promise number of bytes read
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*/
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async peekBuffer(uint8Array, options) {
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const normOptions = this.normalizeOptions(uint8Array, options);
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const res = await fs.read(this.fd, uint8Array, normOptions.offset, normOptions.length, normOptions.position);
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if ((!normOptions.mayBeLess) && res.bytesRead < normOptions.length) {
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throw new EndOfStreamError();
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}
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return res.bytesRead;
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}
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async close() {
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return fs.close(this.fd);
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}
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}
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export async function fromFile(sourceFilePath) {
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const stat = await fs.stat(sourceFilePath);
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if (!stat.isFile) {
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throw new Error(`File not a file: ${sourceFilePath}`);
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}
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const fd = await fs.open(sourceFilePath, 'r');
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return new FileTokenizer(fd, { path: sourceFilePath, size: stat.size });
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}
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