typesxml/dist/FileReader.js

Open source XML library written in TypeScript

"use strict";
/*******************************************************************************
 * Copyright (c) 2023 - 2024 Maxprograms.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse   License 1.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/org/documents/epl-v10.html
 *
 * Contributors:
 *     Maxprograms - initial API and implementation
 *******************************************************************************/
Object.defineProperty(exports, "__esModule", { value: true });
exports.FileReader = void 0;
const fs_1 = require("fs");
class FileReader {
    fileHandle;
    encoding;
    blockSize;
    fileSize;
    position;
    firstRead;
    constructor(path, encoding) {
        let stats = (0, fs_1.statSync)(path, { bigint: false, throwIfNoEntry: true });
        this.fileSize = stats.size;
        this.blockSize = stats.blksize;
        this.fileHandle = (0, fs_1.openSync)(path, 'r');
        if (encoding) {
            this.encoding = encoding;
        }
        else {
            this.encoding = FileReader.detectEncoding(path);
        }
        this.position = 0;
        this.firstRead = true;
    }
    static detectEncoding(path) {
        const fd = (0, fs_1.openSync)(path, 'r');
        let buffer = Buffer.alloc(3);
        let bytesRead = (0, fs_1.readSync)(fd, buffer, 0, 3, 0);
        (0, fs_1.closeSync)(fd);
        if (bytesRead < 3) {
            throw new Error('Error reading BOM: not enough bytes');
        }
        const UTF8 = Buffer.from([-17, -69, -65]);
        const UTF16 = Buffer.from([-2, -1]);
        if (buffer.toString().startsWith(UTF8.toString())) {
            return 'utf8';
        }
        if (buffer.toString().startsWith(UTF16.toString())) {
            return 'utf16le';
        }
        return 'utf8';
    }
    getEncoding() {
        return this.encoding;
    }
    setEncoding(encoding) {
        this.encoding = encoding;
    }
    read() {
        let buffer = Buffer.alloc(this.blockSize, this.encoding);
        let amount = this.blockSize <= this.fileSize - this.position ? this.blockSize : this.fileSize - this.position;
        let bytesRead = (0, fs_1.readSync)(this.fileHandle, buffer, 0, amount, this.position);
        this.position += bytesRead;
        return this.firstRead ? this.skipBOM(buffer, bytesRead) : buffer.toString(this.encoding, 0, bytesRead);
    }
    skipBOM(buffer, bytesRead) {
        this.firstRead = false;
        const utf8Bom = Buffer.from([-17, -69, -65]).toString();
        const utf16Bom = Buffer.from([-2, -1]).toString();
        let result = buffer.toString(this.encoding, 0, bytesRead);
        if (result.startsWith(utf8Bom)) {
            return result.substring(utf8Bom.length);
        }
        if (result.startsWith(utf16Bom)) {
            return result.substring(utf16Bom.length);
        }
        return buffer.toString(this.encoding, 0, bytesRead);
    }
    dataAvailable() {
        return this.position < this.fileSize;
    }
    getFileSize() {
        return this.fileSize;
    }
    closeFile() {
        (0, fs_1.closeSync)(this.fileHandle);
    }
}
exports.FileReader = FileReader;
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