Fleshed out README.md with BNF grammar

README.md

@@ -0,0 +1,85 @@
+# otr-message #
+
+otr-message is a Javascript parser for the message format used in the [Off-the-Record Messaging](http://www.cypherpunks.ca/otr/) instant messaging encryption system, [version 2](http://www.cypherpunks.ca/otr/Protocol-v2-3.0.0.html).
+
+## Installation ##
+
+Coming soon. FIXME
+
+### Dependencies ###
+ReParse. Or possibly the Javascript port of Parsec. Watch this space for updates.
+
+## API ##
+
+Coming soon. FIXME
+
+## Grammar ##
+
+otr-message uses the following (incomplete!) grammar to describe the format of OTR messages:
+
+```
+otr ::= query | error | encoded | tagged_plaintext | plaintext
+query ::= query_prefix versions '?'
+query_prefix ::= '?OTR'
+versions ::= v1_p vN_p
+v1_p ::= '?' | /* empty */
+vN_p ::= 'v' version*
+tagged_plaintext ::= opt_string whitespace_tag opt_string
+opt_string ::= string | /* empty */
+whitespace_tag ::= mandatory_tag opt_v1_tag opt_v2_tag
+mandatory_tag ::= 'x20\x09\x20\x20\x09\x09\x09\x09\x20\x09\x20\x09\x20\x09\x20\x20'
+opt_v1_tag ::= '\x20\x09\x20\x09\x20\x20\x09\x20' | /* empty */
+opt_v2_tag ::= '\x20\x20\x09\x09\x20\x20\x09\x20' | /* empty */
+error ::= error_prefix string
+error_prefix ::= '?OTR Error:'
+plaintext ::= string
+encoded ::= otr_prefix (dh_commit | dh_key | reveal_signature | signature | v1_kem | data) '.'
+otr_prefix ::= '?OTR:'
+otr_byte ::= char
+otr_short ::= byte{2}
+otr_int ::= byte{4}
+otr_mpi ::= otr_int [^\x00]{otr_int_val}
+otr_data ::= otr_int byte{otr_int_val}
+otr_ctr ::= byte{8}
+otr_mac ::= byte{20}
+otr_pubkey ::= otr_short otr_mpi{4}
+otr_sig ::= /* difficult, since this depends on an outside parameter... FIXME */
+dh_commit ::= otr_short otr_byte otr_data otr_data
+dh_key ::= otr_short otr_byte otr_mpi
+reveal_signature ::= otr_short otr_byte otr_data otr_data otr_mac
+signature ::= otr_short otr_byte otr_data otr_mac
+v1_kem ::= FIXME
+data ::= otr_short otr_byte otr_int otr_int otr_int otr_ctr otr_data otr_mac otr_data
+```
+
+## License ##
+
+Copyright (c) 2011, Meredith L. Patterson <clonearmy@gmail.com>
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+* Redistributions of source code must retain the above copyright
+  notice, this list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright
+  notice, this list of conditions and the following disclaimer in the
+  documentation and/or other materials provided with the distribution.
+
+* Neither the name of the <organization> nor the names of its
+  contributors may be used to endorse or promote products derived from
+  this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT
+HOLDER> BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

lib/main.js

@@ -94,11 +94,12 @@ define(["require", "exports", "module"], function(require, exports. module) {
 
   function otr_mpi() {
       var len = this.produce(otr_int);
+      /* need to make sure that no leading zeroes, so otr_byte here is wrong. FIXME. */
       return this.count(otr_byte, len);
   }
 
   function otr_data() {
-      var len = this.produce(otr_len);
+      var len = this.produce(otr_int);
       return this.count(otr_byte, len);
   }