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blast.h revision 1.1 
      1 /*	$NetBSD: blast.h,v 1.1 2006/01/14 20:10:46 christos Exp $	*/
      2 
      3 /* blast.h -- interface for blast.c
      4   Copyright (C) 2003 Mark Adler
      5   version 1.1, 16 Feb 2003
      6 
      7   This software is provided 'as-is', without any express or implied
      8   warranty.  In no event will the author be held liable for any damages
      9   arising from the use of this software.
     10 
     11   Permission is granted to anyone to use this software for any purpose,
     12   including commercial applications, and to alter it and redistribute it
     13   freely, subject to the following restrictions:
     14 
     15   1. The origin of this software must not be misrepresented; you must not
     16      claim that you wrote the original software. If you use this software
     17      in a product, an acknowledgment in the product documentation would be
     18      appreciated but is not required.
     19   2. Altered source versions must be plainly marked as such, and must not be
     20      misrepresented as being the original software.
     21   3. This notice may not be removed or altered from any source distribution.
     22 
     23   Mark Adler    madler (at) alumni.caltech.edu
     24  */
     25 
     26 
     27 /*
     28  * blast() decompresses the PKWare Data Compression Library (DCL) compressed
     29  * format.  It provides the same functionality as the explode() function in
     30  * that library.  (Note: PKWare overused the "implode" verb, and the format
     31  * used by their library implode() function is completely different and
     32  * incompatible with the implode compression method supported by PKZIP.)
     33  */
     34 
     35 
     36 typedef unsigned (*blast_in)(void *how, unsigned char **buf);
     37 typedef int (*blast_out)(void *how, unsigned char *buf, unsigned len);
     38 /* Definitions for input/output functions passed to blast().  See below for
     39  * what the provided functions need to do.
     40  */
     41 
     42 
     43 int blast(blast_in infun, void *inhow, blast_out outfun, void *outhow);
     44 /* Decompress input to output using the provided infun() and outfun() calls.
     45  * On success, the return value of blast() is zero.  If there is an error in
     46  * the source data, i.e. it is not in the proper format, then a negative value
     47  * is returned.  If there is not enough input available or there is not enough
     48  * output space, then a positive error is returned.
     49  *
     50  * The input function is invoked: len = infun(how, &buf), where buf is set by
     51  * infun() to point to the input buffer, and infun() returns the number of
     52  * available bytes there.  If infun() returns zero, then blast() returns with
     53  * an input error.  (blast() only asks for input if it needs it.)  inhow is for
     54  * use by the application to pass an input descriptor to infun(), if desired.
     55  *
     56  * The output function is invoked: err = outfun(how, buf, len), where the bytes
     57  * to be written are buf[0..len-1].  If err is not zero, then blast() returns
     58  * with an output error.  outfun() is always called with len <= 4096.  outhow
     59  * is for use by the application to pass an output descriptor to outfun(), if
     60  * desired.
     61  *
     62  * The return codes are:
     63  *
     64  *   2:  ran out of input before completing decompression
     65  *   1:  output error before completing decompression
     66  *   0:  successful decompression
     67  *  -1:  literal flag not zero or one
     68  *  -2:  dictionary size not in 4..6
     69  *  -3:  distance is too far back
     70  *
     71  * At the bottom of blast.c is an example program that uses blast() that can be
     72  * compiled to produce a command-line decompression filter by defining TEST.
     73  */
     74