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.

All advertising materials mentioning features or use of this software must display the following acknowledgement:

This product includes software developed by the University of California, Berkeley and its contributors.

Neither the name of the University 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 REGENTS 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 THE REGENTS OR CONTRIBUTORS 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.

trvsprnf.c

The Regents of the University of California.

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.

All advertising materials mentioning features or use of this software must display the following acknowledgement: This product includes software developed by the

University of California, Berkeley and its contributors.

Neither the name of the University 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 REGENTS 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 THE REGENTS OR CONTRIBUTORS 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.

trdeflate.c

For conditions of distribution and use, see copyright notice in zlib.h

ALGORITHM

The "deflation" process depends on being able to identify portions of the input text which are identical to earlier input (within a sliding window trailing behind the input

currently being processed).

The most straightforward technique turns out to be the fastest for most input files: try all possible matches and select the longest.

The key feature of this algorithm is that insertions into the string dictionary are very simple and thus fast, and deletions are avoided completely. Insertions are performed

at each input character, whereas string matches are performed only when the previous match ends. So it is preferable to spend more time in matches to allow very fast

string insertions and avoid deletions. The matching algorithm for small strings is inspired from that of Rabin & Karp. A brute force approach is used to find longer strings

when a small match has been found.

A similar algorithm is used in comic (by Jan-Mark Wams) and freeze (by Leonid Broukhis).

A previous version of this file used a more sophisticated algorithm (by Fiala and Greene) which is guaranteed to run in linear amortized time, but has a larger average

cost, uses more memory and is patented.

However the F&G algorithm may be faster for some highly redundant files if the parameter maxChainLength (described below) is too large.

ACKNOWLEDGEMENTS

The idea of lazy evaluation of matches is due to Jan-Mark Wams, and I found it in 'freeze' written by Leonid Broukhis.

Thanks to many people for bug reports and testing.

REFERENCES

Deutsch, L.P., "DEFLATE Compressed Data Format Specification".

Available in http://www.ietf.org/rfc/rfc1951.txt

A description of the Rabin and Karp algorithm is given in the book "Algorithms" by R. Sedgewick, Addison-Wesley, p252.

Fiala,E.R., and Greene,D.H.

Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595

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:

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.

Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.

This notice may not be removed or altered from any source distribution.

Jean-loup Gailly

jloup@gzip.org

Mark Adler

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://www.ietf.org/rfc/rfc1950.txt (zlib format),

rfc1951.txt (deflate format) and rfc1952.txt (gzip format).

trinfback.c