
2hash v 0.2 (2004-05-13)
-----------
2hash simultaneously performs a md5 and a sha1 checksum on file(s).
If you want two checksums for additionally integrity checking, you previously
had to run md5sum and sha1sum serially causing the integrity checks to 
take 100% longer than running a single check alone. 2hash runs both hashes 
in parallel, only having to read the file once. It allows you to 
get both hash values with only about an 8% time increase over md5 alone, 
and only about a 2% time increase over sha1 alone. It runs about 90%
quicker than using both md5 and sha1 one after the other... 


Author & Credits
----------------
2hash was written by Thomas Akin <takin at iss.net>, but based *heavily*
off of Christophe Devine's md5 & sha1 code at http://www.cr0.net:8040
Thanks Chris!


Downloading
-----------
The latest version of 2hash can be downloaded from 
http://www.crossrealm.com/2hash
The source code is at http://www.crossrealm.com/2hash/2hash-v0.2.tar.gz
A static Linux binary is at http://www.crossrealm.com/2hash/2hash-0.2
A WinXP/2000 binary is at http://www.crossrealm.com/2hash/2hash-v0-2wxp.exe
A Win9X binary is at http://www.crossrealm.com/2hash/2hash-v0-2w9x.exe


Compiling & Installation
------------------------
1) unzip the distro 'gunzip 2hash-v0.2.tar.gz'
2) untar the distro 'tar xf 2hash-v0.2.tar'
3) OR do both at the same time 'tar zxf 2hash-v0.2.tar.gz'
4) Change Dir into the distro 'cd 2hash-v0.2'
5) compile the binary 'make'
6) install the binary 'make install'

Note that it will probably be beneficial to play with the optimization levels.
in the Makefile. I've found that O1 or O2 tend to work best on different 
machines. Try -O0 -O1 -O2 -O3 and see which creates the fastest binary on 
your system... 

The binary is installed to /usr/local/bin/2hash. Edit the PREFIX variable in 
the Makefile to change.


Bugs & Comments
---------------
Please let me know what you think, if you find this useful, or if you
find any bugs.

Revision History
----------------
- 2hash-v0.0 - 2004/05/01 - would hash a single file in parallel
- 2hash-v0.1 - 2004/05/13 - turned 2hash into a filter type program that 
               would hash multiple files or stdin
- 2hash-v0.2 - 2004/09/14 - fixed a bug where files were never closed until 
               the program ended, causing it to error out after hashing 
               ~1000 files

Licencing
---------
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA


