<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>JSDoc: Source: packet/packet.js</title>
<script src="scripts/prettify/prettify.js"> </script>
<script src="scripts/prettify/lang-css.js"> </script>
<!--[if lt IE 9]>
<script src="//html5shiv.googlecode.com/svn/trunk/html5.js"></script>
<![endif]-->
<link type="text/css" rel="stylesheet" href="styles/prettify-tomorrow.css">
<link type="text/css" rel="stylesheet" href="styles/jsdoc-default.css">
</head>
<body>
<div id="main">
<h1 class="page-title">Source: packet/packet.js</h1>
<section>
<article>
<pre class="prettyprint source"><code>// GPG4Browsers - An OpenPGP implementation in javascript
// Copyright (C) 2011 Recurity Labs GmbH
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
/**
* @requires enums
* @requires util
* @module packet/packet
*/
var enums = require('../enums.js'),
util = require('../util.js');
module.exports = {
readSimpleLength: function(bytes) {
var len = 0,
offset,
type = bytes.charCodeAt(0);
if (type < 192) {
len = bytes.charCodeAt(0);
offset = 1;
} else if (type < 255) {
len = ((bytes.charCodeAt(0) - 192) << 8) + (bytes.charCodeAt(1)) + 192;
offset = 2;
} else if (type == 255) {
len = util.readNumber(bytes.substr(1, 4));
offset = 5;
}
return {
len: len,
offset: offset
};
},
/**
* Encodes a given integer of length to the openpgp length specifier to a
* string
*
* @param {Integer} length The length to encode
* @return {String} String with openpgp length representation
*/
writeSimpleLength: function(length) {
var result = "";
if (length < 192) {
result += String.fromCharCode(length);
} else if (length > 191 && length < 8384) {
/*
* let a = (total data packet length) - 192 let bc = two octet
* representation of a let d = b + 192
*/
result += String.fromCharCode(((length - 192) >> 8) + 192);
result += String.fromCharCode((length - 192) & 0xFF);
} else {
result += String.fromCharCode(255);
result += util.writeNumber(length, 4);
}
return result;
},
/**
* Writes a packet header version 4 with the given tag_type and length to a
* string
*
* @param {Integer} tag_type Tag type
* @param {Integer} length Length of the payload
* @return {String} String of the header
*/
writeHeader: function(tag_type, length) {
/* we're only generating v4 packet headers here */
var result = "";
result += String.fromCharCode(0xC0 | tag_type);
result += this.writeSimpleLength(length);
return result;
},
/**
* Writes a packet header Version 3 with the given tag_type and length to a
* string
*
* @param {Integer} tag_type Tag type
* @param {Integer} length Length of the payload
* @return {String} String of the header
*/
writeOldHeader: function(tag_type, length) {
var result = "";
if (length < 256) {
result += String.fromCharCode(0x80 | (tag_type << 2));
result += String.fromCharCode(length);
} else if (length < 65536) {
result += String.fromCharCode(0x80 | (tag_type << 2) | 1);
result += util.writeNumber(length, 2);
} else {
result += String.fromCharCode(0x80 | (tag_type << 2) | 2);
result += util.writeNumber(length, 4);
}
return result;
},
/**
* Generic static Packet Parser function
*
* @param {String} input Input stream as string
* @param {integer} position Position to start parsing
* @param {integer} len Length of the input from position on
* @return {Object} Returns a parsed module:packet/packet
*/
read: function(input, position, len) {
// some sanity checks
if (input === null || input.length <= position || input.substring(position).length < 2 || (input.charCodeAt(position) &
0x80) === 0) {
throw new Error("Error during parsing. This message / key is probably not containing a valid OpenPGP format.");
}
var mypos = position;
var tag = -1;
var format = -1;
var packet_length;
format = 0; // 0 = old format; 1 = new format
if ((input.charCodeAt(mypos) & 0x40) !== 0) {
format = 1;
}
var packet_length_type;
if (format) {
// new format header
tag = input.charCodeAt(mypos) & 0x3F; // bit 5-0
} else {
// old format header
tag = (input.charCodeAt(mypos) & 0x3F) >> 2; // bit 5-2
packet_length_type = input.charCodeAt(mypos) & 0x03; // bit 1-0
}
// header octet parsing done
mypos++;
// parsed length from length field
var bodydata = null;
// used for partial body lengths
var real_packet_length = -1;
if (!format) {
// 4.2.1. Old Format Packet Lengths
switch (packet_length_type) {
case 0:
// The packet has a one-octet length. The header is 2 octets
// long.
packet_length = input.charCodeAt(mypos++);
break;
case 1:
// The packet has a two-octet length. The header is 3 octets
// long.
packet_length = (input.charCodeAt(mypos++) << 8) | input.charCodeAt(mypos++);
break;
case 2:
// The packet has a four-octet length. The header is 5
// octets long.
packet_length = (input.charCodeAt(mypos++) << 24) | (input.charCodeAt(mypos++) << 16) | (input.charCodeAt(mypos++) <<
8) | input.charCodeAt(mypos++);
break;
default:
// 3 - The packet is of indeterminate length. The header is 1
// octet long, and the implementation must determine how long
// the packet is. If the packet is in a file, this means that
// the packet extends until the end of the file. In general,
// an implementation SHOULD NOT use indeterminate-length
// packets except where the end of the data will be clear
// from the context, and even then it is better to use a
// definite length, or a new format header. The new format
// headers described below have a mechanism for precisely
// encoding data of indeterminate length.
packet_length = len;
break;
}
} else // 4.2.2. New Format Packet Lengths
{
// 4.2.2.1. One-Octet Lengths
if (input.charCodeAt(mypos) < 192) {
packet_length = input.charCodeAt(mypos++);
util.print_debug("1 byte length:" + packet_length);
// 4.2.2.2. Two-Octet Lengths
} else if (input.charCodeAt(mypos) >= 192 && input.charCodeAt(mypos) < 224) {
packet_length = ((input.charCodeAt(mypos++) - 192) << 8) + (input.charCodeAt(mypos++)) + 192;
util.print_debug("2 byte length:" + packet_length);
// 4.2.2.4. Partial Body Lengths
} else if (input.charCodeAt(mypos) > 223 && input.charCodeAt(mypos) < 255) {
packet_length = 1 << (input.charCodeAt(mypos++) & 0x1F);
util.print_debug("4 byte length:" + packet_length);
// EEEK, we're reading the full data here...
var mypos2 = mypos + packet_length;
bodydata = input.substring(mypos, mypos + packet_length);
var tmplen;
while (true) {
if (input.charCodeAt(mypos2) < 192) {
tmplen = input.charCodeAt(mypos2++);
packet_length += tmplen;
bodydata += input.substring(mypos2, mypos2 + tmplen);
mypos2 += tmplen;
break;
} else if (input.charCodeAt(mypos2) >= 192 && input.charCodeAt(mypos2) < 224) {
tmplen = ((input.charCodeAt(mypos2++) - 192) << 8) + (input.charCodeAt(mypos2++)) + 192;
packet_length += tmplen;
bodydata += input.substring(mypos2, mypos2 + tmplen);
mypos2 += tmplen;
break;
} else if (input.charCodeAt(mypos2) > 223 && input.charCodeAt(mypos2) < 255) {
tmplen = 1 << (input.charCodeAt(mypos2++) & 0x1F);
packet_length += tmplen;
bodydata += input.substring(mypos2, mypos2 + tmplen);
mypos2 += tmplen;
} else {
mypos2++;
tmplen = (input.charCodeAt(mypos2++) << 24) | (input.charCodeAt(mypos2++) << 16) | (input[mypos2++]
.charCodeAt() << 8) | input.charCodeAt(mypos2++);
bodydata += input.substring(mypos2, mypos2 + tmplen);
packet_length += tmplen;
mypos2 += tmplen;
break;
}
}
real_packet_length = mypos2;
// 4.2.2.3. Five-Octet Lengths
} else {
mypos++;
packet_length = (input.charCodeAt(mypos++) << 24) | (input.charCodeAt(mypos++) << 16) | (input.charCodeAt(mypos++) <<
8) | input.charCodeAt(mypos++);
}
}
// if there was'nt a partial body length: use the specified
// packet_length
if (real_packet_length == -1) {
real_packet_length = packet_length;
}
if (bodydata === null) {
bodydata = input.substring(mypos, mypos + real_packet_length);
}
return {
tag: tag,
packet: bodydata,
offset: mypos + real_packet_length
};
}
};
</code></pre>
</article>
</section>
</div>
<nav>
<h2><a href="index.html">Index</a></h2><h3>Modules</h3><ul><li><a href="module-async_proxy.html">async_proxy</a></li><li><a href="module-cleartext.html">cleartext</a></li><li><a href="module-config.html">config</a></li><li><a href="config.html">config/config</a></li><li><a href="localStorage.html">config/localStorage</a></li><li><a href="module-crypto.html">crypto</a></li><li><a href="cfb.html">crypto/cfb</a></li><li><a href="cipher.html">crypto/cipher</a></li><li><a href="aes.html">crypto/cipher/aes</a></li><li><a href="blowfish.html">crypto/cipher/blowfish</a></li><li><a href="cast5.html">crypto/cipher/cast5</a></li><li><a href="des.html">crypto/cipher/des</a></li><li><a href="twofish.html">crypto/cipher/twofish</a></li><li><a href="crypto.html">crypto/crypto</a></li><li><a href="hash.html">crypto/hash</a></li><li><a href="md5.html">crypto/hash/md5</a></li><li><a href="ripe-md.html">crypto/hash/ripe-md</a></li><li><a href="sha.html">crypto/hash/sha</a></li><li><a href="pkcs1.html">crypto/pkcs1</a></li><li><a href="public_key.html">crypto/public_key</a></li><li><a href="dsa.html">crypto/public_key/dsa</a></li><li><a href="elgamal.html">crypto/public_key/elgamal</a></li><li><a href="jsbn.html">crypto/public_key/jsbn</a></li><li><a href="rsa.html">crypto/public_key/rsa</a></li><li><a href="random.html">crypto/random</a></li><li><a href="signature.html">crypto/signature</a></li><li><a href="armor.html">encoding/armor</a></li><li><a href="base64.html">encoding/base64</a></li><li><a href="module-enums.html">enums</a></li><li><a href="module-key.html">key</a></li><li><a href="module-keyring.html">keyring</a></li><li><a href="keyring.html">keyring/keyring</a></li><li><a href="localstore.html">keyring/localstore</a></li><li><a href="module-message.html">message</a></li><li><a href="module-openpgp.html">openpgp</a></li><li><a href="module-packet.html">packet</a></li><li><a href="compressed.html">packet/compressed</a></li><li><a href="literal.html">packet/literal</a></li><li><a href="marker.html">packet/marker</a></li><li><a href="one_pass_signature.html">packet/one_pass_signature</a></li><li><a href="packet.html">packet/packet</a></li><li><a href="packetlist.html">packet/packetlist</a></li><li><a href="public_key_.html">packet/public_key</a></li><li><a href="public_key_encrypted_session_key.html">packet/public_key_encrypted_session_key</a></li><li><a href="public_subkey.html">packet/public_subkey</a></li><li><a href="secret_key.html">packet/secret_key</a></li><li><a href="secret_subkey.html">packet/secret_subkey</a></li><li><a href="signature_.html">packet/signature</a></li><li><a href="sym_encrypted_integrity_protected.html">packet/sym_encrypted_integrity_protected</a></li><li><a href="sym_encrypted_session_key.html">packet/sym_encrypted_session_key</a></li><li><a href="symmetrically_encrypted.html">packet/symmetrically_encrypted</a></li><li><a href="trust.html">packet/trust</a></li><li><a href="user_attribute.html">packet/user_attribute</a></li><li><a href="userid.html">packet/userid</a></li><li><a href="keyid.html">type/keyid</a></li><li><a href="mpi.html">type/mpi</a></li><li><a href="s2k.html">type/s2k</a></li><li><a href="module-util.html">util</a></li></ul><h3>Classes</h3><ul><li><a href="JXG.Util.html">JXG.Util</a></li><li><a href="module-async_proxy-AsyncProxy.html">async_proxy~AsyncProxy</a></li><li><a href="module-cleartext-CleartextMessage.html">cleartext~CleartextMessage</a></li><li><a href="localStorage-LocalStorage.html">config/localStorage~LocalStorage</a></li><li><a href="keyring-Keyring.html">keyring/keyring~Keyring</a></li><li><a href="module-key-Key.html">key~Key</a></li><li><a href="module-key-SubKey.html">key~SubKey</a></li><li><a href="module-key-User.html">key~User</a></li><li><a href="module-message-Message.html">message~Message</a></li><li><a href="compressed-Compressed.html">packet/compressed~Compressed</a></li><li><a href="literal-Literal.html">packet/literal~Literal</a></li><li><a href="marker-Marker.html">packet/marker~Marker</a></li><li><a href="one_pass_signature-OnePassSignature.html">packet/one_pass_signature~OnePassSignature</a></li><li><a href="packetlist-Packetlist.html">packet/packetlist~Packetlist</a></li><li><a href="public_key_encrypted_session_key-PublicKeyEncryptedSessionKey.html">packet/public_key_encrypted_session_key~PublicKeyEncryptedSessionKey</a></li><li><a href="public_key-PublicKey.html">packet/public_key~PublicKey</a></li><li><a href="public_subkey-PublicSubkey.html">packet/public_subkey~PublicSubkey</a></li><li><a href="secret_key-SecretKey.html">packet/secret_key~SecretKey</a></li><li><a href="secret_subkey-SecretSubkey.html">packet/secret_subkey~SecretSubkey</a></li><li><a href="signature-Signature.html">packet/signature~Signature</a></li><li><a href="sym_encrypted_integrity_protected-SymEncryptedIntegrityProtected.html">packet/sym_encrypted_integrity_protected~SymEncryptedIntegrityProtected</a></li><li><a href="sym_encrypted_session_key-SymEncryptedSessionKey.html">packet/sym_encrypted_session_key~SymEncryptedSessionKey</a></li><li><a href="symmetrically_encrypted-SymmetricallyEncrypted.html">packet/symmetrically_encrypted~SymmetricallyEncrypted</a></li><li><a href="trust-Trust.html">packet/trust~Trust</a></li><li><a href="user_attribute-UserAttribute.html">packet/user_attribute~UserAttribute</a></li><li><a href="userid-Userid.html">packet/userid~Userid</a></li><li><a href="keyid-Keyid.html">type/keyid~Keyid</a></li><li><a href="mpi-MPI.html">type/mpi~MPI</a></li><li><a href="s2k-S2K.html">type/s2k~S2K</a></li></ul>
</nav>
<br clear="both">
<footer>
Documentation generated by <a href="https://github.com/jsdoc3/jsdoc">JSDoc 3.2.2</a> on Wed Feb 12 2014 15:09:01 GMT+0100 (MEZ)
</footer>
<script> prettyPrint(); </script>
<script src="scripts/linenumber.js"> </script>
</body>
</html>