The original adler32.c file contained the following copyright notice:

> Copyright (C) 1995-2013 Jean-loup Gailly and Mark Adler
>
> This software is provided 'as-is', without any express or implied
> warranty.  In no event will the authors be held liable for any damages
> arising from the use of this software.
>
> Permission is granted to anyone to use this software for any purpose,
> including commercial applications, and to alter it and redistribute it
> freely, subject to the following restrictions:
>
> 1. The origin of this software must not be misrepresented; you must not
>  claim that you wrote the original software. If you use this software
>  in a product, an acknowledgment in the product documentation would be
>  appreciated but is not required.
> 2. Altered source versions must be plainly marked as such, and must not be
>  misrepresented as being the original software.
> 3. This notice may not be removed or altered from any source distribution.
>
> Jean-loup Gailly        Mark Adler
> jloup@gzip.org          madler@alumni.caltech.edu
>
>
> The data format used by the zlib library is described by RFCs (Request for
> Comments) 1950 to 1952 in the files http://tools.ietf.org/html/rfc1950
> (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format).

The coffee-script port is copyright 2014, Jason Walton, and licensed under the same terms.