zlib/contrib/blast/blast.h

   1 /* blast.h -- interface for blast.c
   2   Copyright (C) 2003, 2012, 2013 Mark Adler
   3   version 1.3, 24 Aug 2013
   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  * The binary mode for stdio functions should be used to assure that the
  33  * compressed data is not corrupted when read or written.  For example:
  34  * fopen(..., "rb") and fopen(..., "wb").
  35  */
  36
  37
  38 typedef unsigned (*blast_in)(void *how, unsigned char **buf);
  39 typedef int (*blast_out)(void *how, unsigned char *buf, unsigned len);
  40 /* Definitions for input/output functions passed to blast().  See below for
  41  * what the provided functions need to do.
  42  */
  43
  44
  45 int blast(blast_in infun, void *inhow, blast_out outfun, void *outhow,
  46           unsigned *left, unsigned char **in);
  47 /* Decompress input to output using the provided infun() and outfun() calls.
  48  * On success, the return value of blast() is zero.  If there is an error in
  49  * the source data, i.e. it is not in the proper format, then a negative value
  50  * is returned.  If there is not enough input available or there is not enough
  51  * output space, then a positive error is returned.
  52  *
  53  * The input function is invoked: len = infun(how, &buf), where buf is set by
  54  * infun() to point to the input buffer, and infun() returns the number of
  55  * available bytes there.  If infun() returns zero, then blast() returns with
  56  * an input error.  (blast() only asks for input if it needs it.)  inhow is for
  57  * use by the application to pass an input descriptor to infun(), if desired.
  58  *
  59  * If left and in are not NULL and *left is not zero when blast() is called,
  60  * then the *left bytes are *in are consumed for input before infun() is used.
  61  *
  62  * The output function is invoked: err = outfun(how, buf, len), where the bytes
  63  * to be written are buf[0..len-1].  If err is not zero, then blast() returns
  64  * with an output error.  outfun() is always called with len <= 4096.  outhow
  65  * is for use by the application to pass an output descriptor to outfun(), if
  66  * desired.
  67  *
  68  * If there is any unused input, *left is set to the number of bytes that were
  69  * read and *in points to them.  Otherwise *left is set to zero and *in is set
  70  * to NULL.  If left or in are NULL, then they are not set.
  71  *
  72  * The return codes are:
  73  *
  74  *   2:  ran out of input before completing decompression
  75  *   1:  output error before completing decompression
  76  *   0:  successful decompression
  77  *  -1:  literal flag not zero or one
  78  *  -2:  dictionary size not in 4..6
  79  *  -3:  distance is too far back
  80  *
  81  * At the bottom of blast.c is an example program that uses blast() that can be
  82  * compiled to produce a command-line decompression filter by defining TEST.
  83  */