/*      $NetBSD: zcat.c,v 1.5 2017/01/12 01:58:03 christos Exp $        */

/* mini zcat.c -- a minimal zcat using the zlib compression library
 * Copyright (C) 1995-1996 Jean-loup Gailly.
 * For conditions of distribution and use, see copyright notice in zlib.h 
 */

/*
 * Credits, History:
 * This program is a reduced version of the minigzip.c
 * program originally written by Jean-loup Gailly.
 * This reduction is the work of Gordon Ross.
 */

#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>

#include "zlib.h"

#define BUFLEN 4096

char *prog;

static void error(const char *, ...) __printflike(1, 2);
static void gz_uncompress(gzFile, int);

/* ===========================================================================
 * Display error message and exit
 */
static void
error(const char *fmt, ...)
{
        char buf[1024];
        va_list ap;
        int l;

        l = snprintf_ss(buf, sizeof(buf), "%s: ", prog);
        write(STDERR_FILENO, buf, l);
        va_start(ap, fmt);
        l = vsnprintf_ss(buf, sizeof(buf), fmt, ap);
        va_end(ap);
        write(STDERR_FILENO, buf, l);
        _exit(EXIT_SUCCESS);
}

/* ===========================================================================
 * Uncompress input to output then close both files.
 */
static void
gz_uncompress(gzFile in, int out)
{
        char buf[BUFLEN];
        int len;
        int err;

        for (;;) {
                len = gzread(in, buf, sizeof(buf));
                if (len < 0)
                        error ("%s", gzerror(in, &err));
                if (len == 0)
                        break;

                if ((int)write(out, buf, (size_t)len) != len) {
                        error("failed fwrite");
                }
        }
        if (close(out))
                error("failed fclose");

        if (gzclose(in) != Z_OK)
                error("failed gzclose");
}


/* ===========================================================================
 * Usage:  zcat [files...]
 */

int
main(int argc, char *argv[])
{
        gzFile zfp;

        /* save program name and skip */
        prog = argv[0];
        argc--, argv++;

        /* ignore any switches */
        while (*argv && (**argv == '-')) {
                argc--, argv++;
        }

        if (argc == 0) {
                zfp = gzdopen(STDIN_FILENO, "rb");
                if (zfp == NULL)
                        error("can't gzdopen stdin");
                gz_uncompress(zfp, STDOUT_FILENO);
                return 0;
        }

        do {
                /* file_uncompress(*argv); */
                zfp = gzopen(*argv, "rb");
                if (zfp == NULL) {
                        error("can't gzopen `%s'", *argv);
                        _exit(EXIT_FAILURE);
                }
                gz_uncompress(zfp, STDOUT_FILENO);
        } while (argv++, --argc);
        return 0; /* to avoid warning */
}


/*
 * XXX: hacks to keep gzio.c from pulling in deflate stuff
 */

int deflateInit2_(z_streamp strm, int  level, int  method,
    int windowBits, int memLevel, int strategy,
    const char *version, int stream_size)
{

        return -1;
}

int deflate(z_streamp strm, int flush)
{

        return -1;
}

int deflateEnd(z_streamp strm)
{

        return -1;
}

int deflateParams(z_streamp strm, int level, int strategy)
{

        return Z_STREAM_ERROR;
}