source: trip-planner-front/node_modules/sshpk/lib/formats/x509-pem.js

// Copyright 2016 Joyent, Inc.

var x509 = require('./x509');

module.exports = {
        read: read,
        verify: x509.verify,
        sign: x509.sign,
        write: write
};

var assert = require('assert-plus');
var asn1 = require('asn1');
var Buffer = require('safer-buffer').Buffer;
var algs = require('../algs');
var utils = require('../utils');
var Key = require('../key');
var PrivateKey = require('../private-key');
var pem = require('./pem');
var Identity = require('../identity');
var Signature = require('../signature');
var Certificate = require('../certificate');

function read(buf, options) {
        if (typeof (buf) !== 'string') {
                assert.buffer(buf, 'buf');
                buf = buf.toString('ascii');
        }

        var lines = buf.trim().split(/[\r\n]+/g);

        var m;
        var si = -1;
        while (!m && si < lines.length) {
                m = lines[++si].match(/*JSSTYLED*/
                    /[-]+[ ]*BEGIN CERTIFICATE[ ]*[-]+/);
        }
        assert.ok(m, 'invalid PEM header');

        var m2;
        var ei = lines.length;
        while (!m2 && ei > 0) {
                m2 = lines[--ei].match(/*JSSTYLED*/
                    /[-]+[ ]*END CERTIFICATE[ ]*[-]+/);
        }
        assert.ok(m2, 'invalid PEM footer');

        lines = lines.slice(si, ei + 1);

        var headers = {};
        while (true) {
                lines = lines.slice(1);
                m = lines[0].match(/*JSSTYLED*/
                    /^([A-Za-z0-9-]+): (.+)$/);
                if (!m)
                        break;
                headers[m[1].toLowerCase()] = m[2];
        }

        /* Chop off the first and last lines */
        lines = lines.slice(0, -1).join('');
        buf = Buffer.from(lines, 'base64');

        return (x509.read(buf, options));
}

function write(cert, options) {
        var dbuf = x509.write(cert, options);

        var header = 'CERTIFICATE';
        var tmp = dbuf.toString('base64');
        var len = tmp.length + (tmp.length / 64) +
            18 + 16 + header.length*2 + 10;
        var buf = Buffer.alloc(len);
        var o = 0;
        o += buf.write('-----BEGIN ' + header + '-----\n', o);
        for (var i = 0; i < tmp.length; ) {
                var limit = i + 64;
                if (limit > tmp.length)
                        limit = tmp.length;
                o += buf.write(tmp.slice(i, limit), o);
                buf[o++] = 10;
                i = limit;
        }
        o += buf.write('-----END ' + header + '-----\n', o);

        return (buf.slice(0, o));
}