FileTokenizer.jsā¢2.28 kB
import { AbstractTokenizer } from './AbstractTokenizer.js';
import { EndOfStreamError } from './stream/index.js';
import { open as fsOpen } from 'node:fs/promises';
export class FileTokenizer extends AbstractTokenizer {
/**
* Create tokenizer from provided file path
* @param sourceFilePath File path
*/
static async fromFile(sourceFilePath) {
const fileHandle = await fsOpen(sourceFilePath, 'r');
const stat = await fileHandle.stat();
return new FileTokenizer(fileHandle, { fileInfo: { path: sourceFilePath, size: stat.size } });
}
constructor(fileHandle, options) {
super(options);
this.fileHandle = fileHandle;
this.fileInfo = options.fileInfo;
}
/**
* Read buffer from file
* @param uint8Array - Uint8Array to write result to
* @param options - Read behaviour options
* @returns Promise number of bytes read
*/
async readBuffer(uint8Array, options) {
const normOptions = this.normalizeOptions(uint8Array, options);
this.position = normOptions.position;
if (normOptions.length === 0)
return 0;
const res = await this.fileHandle.read(uint8Array, 0, normOptions.length, normOptions.position);
this.position += res.bytesRead;
if (res.bytesRead < normOptions.length && (!options || !options.mayBeLess)) {
throw new EndOfStreamError();
}
return res.bytesRead;
}
/**
* Peek buffer from file
* @param uint8Array - Uint8Array (or Buffer) to write data to
* @param options - Read behaviour options
* @returns Promise number of bytes read
*/
async peekBuffer(uint8Array, options) {
const normOptions = this.normalizeOptions(uint8Array, options);
const res = await this.fileHandle.read(uint8Array, 0, normOptions.length, normOptions.position);
if ((!normOptions.mayBeLess) && res.bytesRead < normOptions.length) {
throw new EndOfStreamError();
}
return res.bytesRead;
}
async close() {
await this.fileHandle.close();
return super.close();
}
setPosition(position) {
this.position = position;
}
supportsRandomAccess() {
return true;
}
}