How to use the asn1.BerReader function in asn1

throw (e);
		});
		cipherStream.write(buf);
		cipherStream.end();
		while ((chunk = cipherStream.read()) !== null)
			chunks.push(chunk);
		buf = Buffer.concat(chunks);
	}

	/* The new OpenSSH internal format abuses PEM headers */
	if (alg && alg.toLowerCase() === 'openssh')
		return (sshpriv.readSSHPrivate(type, buf, options));
	if (alg && alg.toLowerCase() === 'ssh2')
		return (rfc4253.readType(type, buf, options));

	var der = new asn1.BerReader(buf);
	der.originalInput = input;

	/*
	 * All of the PEM file types start with a sequence tag, so chop it
	 * off here
	 */
	der.readSequence();

	/* PKCS#1 type keys name an algorithm in the banner explicitly */
	if (alg) {
		if (forceType)
			assert.strictEqual(forceType, 'pkcs1');
		return (pkcs1.readPkcs1(alg, type, der));
	} else {
		if (forceType)
			assert.strictEqual(forceType, 'pkcs8');

throw (e);
		});
		cipherStream.write(buf);
		cipherStream.end();
		while ((chunk = cipherStream.read()) !== null)
			chunks.push(chunk);
		buf = Buffer.concat(chunks);
	}

	/* The new OpenSSH internal format abuses PEM headers */
	if (alg && alg.toLowerCase() === 'openssh')
		return (sshpriv.readSSHPrivate(type, buf, options));
	if (alg && alg.toLowerCase() === 'ssh2')
		return (rfc4253.readType(type, buf, options));

	var der = new asn1.BerReader(buf);
	der.originalInput = input;

	/*
	 * All of the PEM file types start with a sequence tag, so chop it
	 * off here
	 */
	der.readSequence();

	/* PKCS#1 type keys name an algorithm in the banner explicitly */
	if (alg) {
		if (forceType)
			assert.strictEqual(forceType, 'pkcs1');
		return (pkcs1.readPkcs1(alg, type, der));
	} else {
		if (forceType)
			assert.strictEqual(forceType, 'pkcs8');

function read(buf, options) {
	if (typeof (buf) === 'string') {
		buf = Buffer.from(buf, 'binary');
	}
	assert.buffer(buf, 'buf');

	var der = new asn1.BerReader(buf);

	der.readSequence();
	if (Math.abs(der.length - der.remain) > 1) {
		throw (new Error('DER sequence does not contain whole byte ' +
		    'stream'));
	}

	var tbsStart = der.offset;
	der.readSequence();
	var sigOffset = der.offset + der.length;
	var tbsEnd = sigOffset;

	if (der.peek() === Local(0)) {
		der.readSequence(Local(0));
		var version = der.readInt();
		assert.ok(version <= 3,

function parseDSAasn1(data, type, format, opts) {
	var der = new asn1.BerReader(data);
	der.readSequence();
	var r = der.readString(asn1.Ber.Integer, true);
	var s = der.readString(asn1.Ber.Integer, true);

	opts.parts.push({name: 'r', data: utils.mpNormalize(r)});
	opts.parts.push({name: 's', data: utils.mpNormalize(s)});

	return (new Signature(opts));
}

function parseDSAasn1(data, type, format, opts) {
	var der = new asn1.BerReader(data);
	der.readSequence();
	var r = der.readString(asn1.Ber.Integer, true);
	var s = der.readString(asn1.Ber.Integer, true);

	opts.parts.push({name: 'r', data: utils.mpNormalize(r)});
	opts.parts.push({name: 's', data: utils.mpNormalize(s)});

	return (new Signature(opts));
}

function parseDSAasn1(data, type, format, opts) {
	var der = new asn1.BerReader(data);
	der.readSequence();
	var r = der.readString(asn1.Ber.Integer, true);
	var s = der.readString(asn1.Ber.Integer, true);

	opts.parts.push({name: 'r', data: utils.mpNormalize(r)});
	opts.parts.push({name: 's', data: utils.mpNormalize(s)});

	return (new Signature(opts));
}

function parseDSAasn1(data, type, format, opts) {
	var der = new asn1.BerReader(data);
	der.readSequence();
	var r = der.readString(asn1.Ber.Integer, true);
	var s = der.readString(asn1.Ber.Integer, true);

	opts.parts.push({name: 'r', data: utils.mpNormalize(r)});
	opts.parts.push({name: 's', data: utils.mpNormalize(s)});

	return (new Signature(opts));
}

function read(buf, options) {
	if (typeof (buf) === 'string') {
		buf = new Buffer(buf, 'binary');
	}
	assert.buffer(buf, 'buf');

	var der = new asn1.BerReader(buf);

	der.readSequence();
	if (Math.abs(der.length - der.remain) > 1) {
		throw (new Error('DER sequence does not contain whole byte ' +
		    'stream'));
	}

	var tbsStart = der.offset;
	der.readSequence();
	var sigOffset = der.offset + der.length;
	var tbsEnd = sigOffset;

	if (der.peek() === Local(0)) {
		der.readSequence(Local(0));
		var version = der.readInt();
		assert.ok(version <= 3,