1 /* blast.h -- interface for blast.c

     2   Copyright (C) 2003 Mark Adler

     3   version 1.1, 16 Feb 2003

     4 

     5   This software is provided 'as-is', without any express or implied

     6   warranty.  In no event will the author be held liable for any damages

     7   arising from the use of this software.

     8 

     9   Permission is granted to anyone to use this software for any purpose,

    10   including commercial applications, and to alter it and redistribute it

    11   freely, subject to the following restrictions:

    12 

    13   1. The origin of this software must not be misrepresented; you must not

    14      claim that you wrote the original software. If you use this software

    15      in a product, an acknowledgment in the product documentation would be

    16      appreciated but is not required.

    17   2. Altered source versions must be plainly marked as such, and must not be

    18      misrepresented as being the original software.

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

    20 

    21   Mark Adler    madler@alumni.caltech.edu

    22  */

    23 

    24 

    25 /*

    26  * blast() decompresses the PKWare Data Compression Library (DCL) compressed

    27  * format.  It provides the same functionality as the explode() function in

    28  * that library.  (Note: PKWare overused the "implode" verb, and the format

    29  * used by their library implode() function is completely different and

    30  * incompatible with the implode compression method supported by PKZIP.)

    31  */

    32 

    33 

    34 typedef unsigned (*blast_in)(void *how, unsigned char **buf);

    35 typedef int (*blast_out)(void *how, unsigned char *buf, unsigned len);

    36 /* Definitions for input/output functions passed to blast().  See below for

    37  * what the provided functions need to do.

    38  */

    39 

    40 

    41 int blast(blast_in infun, void *inhow, blast_out outfun, void *outhow);

    42 /* Decompress input to output using the provided infun() and outfun() calls.

    43  * On success, the return value of blast() is zero.  If there is an error in

    44  * the source data, i.e. it is not in the proper format, then a negative value

    45  * is returned.  If there is not enough input available or there is not enough

    46  * output space, then a positive error is returned.

    47  *

    48  * The input function is invoked: len = infun(how, &buf), where buf is set by

    49  * infun() to point to the input buffer, and infun() returns the number of

    50  * available bytes there.  If infun() returns zero, then blast() returns with

    51  * an input error.  (blast() only asks for input if it needs it.)  inhow is for

    52  * use by the application to pass an input descriptor to infun(), if desired.

    53  *

    54  * The output function is invoked: err = outfun(how, buf, len), where the bytes

    55  * to be written are buf[0..len-1].  If err is not zero, then blast() returns

    56  * with an output error.  outfun() is always called with len <= 4096.  outhow

    57  * is for use by the application to pass an output descriptor to outfun(), if

    58  * desired.

    59  *

    60  * The return codes are:

    61  *

    62  *   2:  ran out of input before completing decompression

    63  *   1:  output error before completing decompression

    64  *   0:  successful decompression

    65  *  -1:  literal flag not zero or one

    66  *  -2:  dictionary size not in 4..6

    67  *  -3:  distance is too far back

    68  *

    69  * At the bottom of blast.c is an example program that uses blast() that can be

    70  * compiled to produce a command-line decompression filter by defining TEST.

    71  */