/* gun.c -- simple gunzip to give an example of the use of inflateBack()
 * Copyright (C) 2003, 2005, 2008, 2010, 2012 Mark Adler
 * For conditions of distribution and use, see copyright notice in zlib.h
   Version 1.7  12 August 2012  Mark Adler */

/* Version history:
   1.0  16 Feb 2003  First version for testing of inflateBack()
   1.1  21 Feb 2005  Decompress concatenated gzip streams
                     Remove use of "this" variable (C++ keyword)
                     Fix return value for in()
                     Improve allocation failure checking
                     Add typecasting for void * structures
                     Add -h option for command version and usage
                     Add a bunch of comments
   1.2  20 Mar 2005  Add Unix compress (LZW) decompression
                     Copy file attributes from input file to output file
   1.3  12 Jun 2005  Add casts for error messages [Oberhumer]
   1.4   8 Dec 2006  LZW decompression speed improvements
   1.5   9 Feb 2008  Avoid warning in latest version of gcc
   1.6  17 Jan 2010  Avoid signed/unsigned comparison warnings
   1.7  12 Aug 2012  Update for z_const usage in zlib 1.2.8
 */

/*
   gun [ -t ] [ name ... ]

   decompresses the data in the named gzip files.  If no arguments are given,
   gun will decompress from stdin to stdout.  The names must end in .gz, -gz,

    int infile;
    unsigned char *inbuf;
};

/* Load input buffer, assumed to be empty, and return bytes loaded and a
   pointer to them.  read() is called until the buffer is full, or until it
   returns end-of-file or error.  Return 0 on error. */
local unsigned in(void *in_desc, z_const unsigned char **buf)
{
    int ret;
    unsigned len;
    unsigned char *next;
    struct ind *me = (struct ind *)in_desc;

    next = me->inbuf;

   of buffered input at next.  strm is used for passing error information back
   to gunpipe().

   lunpipe() will return Z_OK on success, Z_BUF_ERROR for an unexpected end of
   file, read error, or write error (a write error indicated by strm->next_in
   not equal to Z_NULL), or Z_DATA_ERROR for invalid input.
 */
local int lunpipe(unsigned have, z_const unsigned char *next, struct ind *indp,
                  int outfile, z_stream *strm)
{
    int last;                   /* last byte read by NEXT(), or -1 if EOF */
    unsigned chunk;             /* bytes left in current chunk */
    int left;                   /* bits left in rem */
    unsigned rem;               /* unused bits from input */
    int bits;                   /* current bits per code */

   prematurely or a write error occurs, or Z_ERRNO if junk (not a another gzip
   stream) follows a valid gzip stream.
 */
local int gunpipe(z_stream *strm, int infile, int outfile)
{
    int ret, first, last;
    unsigned have, flags, len;
    z_const unsigned char *next = NULL;
    struct ind ind, *indp;
    struct outd outd;

    /* setup input buffer */
    ind.infile = infile;
    ind.inbuf = inbuf;
    indp = &ind;