source: node_modules/nodemailer/lib/mime-node/le-unix.js

'use strict';

const stream = require('stream');
const Transform = stream.Transform;

/**
 * Ensures that only <LF> is used for linebreaks
 *
 * @param {Object} options Stream options
 */
class LeWindows extends Transform {
    constructor(options) {
        super(options);
        // init Transform
        this.options = options || {};
    }

    /**
     * Escapes dots
     */
    _transform(chunk, encoding, done) {
        let buf;
        let lastPos = 0;

        for (let i = 0, len = chunk.length; i < len; i++) {
            if (chunk[i] === 0x0d) {
                // \n
                buf = chunk.slice(lastPos, i);
                lastPos = i + 1;
                this.push(buf);
            }
        }
        if (lastPos && lastPos < chunk.length) {
            buf = chunk.slice(lastPos);
            this.push(buf);
        } else if (!lastPos) {
            this.push(chunk);
        }
        done();
    }
}

module.exports = LeWindows;