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zcat.c revision 1.4 
      1 /*	$NetBSD: zcat.c,v 1.4 2011/05/19 22:23:12 tsutsui Exp $	*/
      2 
      3 /* mini zcat.c -- a minimal zcat using the zlib compression library
      4  * Copyright (C) 1995-1996 Jean-loup Gailly.
      5  * For conditions of distribution and use, see copyright notice in zlib.h
      6  */
      7 
      8 /*
      9  * Credits, History:
     10  * This program is a reduced version of the minigzip.c
     11  * program originally written by Jean-loup Gailly.
     12  * This reduction is the work of Gordon Ross.
     13  */
     14 
     15 #include <stdio.h>
     16 #include <string.h>
     17 #include <stdlib.h>
     18 
     19 #include "zlib.h"
     20 
     21 #define BUFLEN 4096
     22 
     23 char *prog;
     24 
     25 void error(const char *msg);
     26 void gz_uncompress(gzFile in, FILE   *out);
     27 int  main(int argc, char *argv[]);
     28 
     29 /* ===========================================================================
     30  * Display error message and exit
     31  */
     32 void error(const char *msg)
     33 {
     34 
     35 	fprintf(stderr, "%s: %s\n", prog, msg);
     36 	exit(EXIT_SUCCESS);
     37 }
     38 
     39 /* ===========================================================================
     40  * Uncompress input to output then close both files.
     41  */
     42 void gz_uncompress(gzFile in, FILE *out)
     43 {
     44 	char buf[BUFLEN];
     45 	int len;
     46 	int err;
     47 
     48 	for (;;) {
     49 		len = gzread(in, buf, sizeof(buf));
     50 		if (len < 0)
     51 			error (gzerror(in, &err));
     52 		if (len == 0)
     53 			break;
     54 
     55 		if ((int)fwrite(buf, 1, (unsigned)len, out) != len) {
     56 			error("failed fwrite");
     57 		}
     58 	}
     59 	if (fclose(out))
     60 		error("failed fclose");
     61 
     62 	if (gzclose(in) != Z_OK)
     63 		error("failed gzclose");
     64 }
     65 
     66 
     67 /* ===========================================================================
     68  * Usage:  zcat [files...]
     69  */
     70 
     71 int main(int argc, char *argv[])
     72 {
     73 	gzFile zfp;
     74 
     75 	/* save program name and skip */
     76 	prog = argv[0];
     77 	argc--, argv++;
     78 
     79 	/* ignore any switches */
     80 	while (*argv && (**argv == '-')) {
     81 		argc--, argv++;
     82 	}
     83 
     84 	if (argc == 0) {
     85 		zfp = gzdopen(fileno(stdin), "rb");
     86 		if (zfp == NULL)
     87 			error("can't gzdopen stdin");
     88 		gz_uncompress(zfp, stdout);
     89 		return 0;
     90 	}
     91 
     92 	do {
     93 		/* file_uncompress(*argv); */
     94 		zfp = gzopen(*argv, "rb");
     95 		if (zfp == NULL) {
     96 			fprintf(stderr, "%s: can't gzopen %s\n", prog, *argv);
     97 			exit(EXIT_FAILURE);
     98 		}
     99 		gz_uncompress(zfp, stdout);
    100 	} while (argv++, --argc);
    101 	return 0; /* to avoid warning */
    102 }
    103 
    104 
    105 /*
    106  * XXX: hacks to keep gzio.c from pulling in deflate stuff
    107  */
    108 
    109 int deflateInit2_(z_streamp strm, int  level, int  method,
    110     int windowBits, int memLevel, int strategy,
    111     const char *version, int stream_size)
    112 {
    113 
    114 	return -1;
    115 }
    116 
    117 int deflate(z_streamp strm, int flush)
    118 {
    119 
    120 	return -1;
    121 }
    122 
    123 int deflateEnd(z_streamp strm)
    124 {
    125 
    126 	return -1;
    127 }
    128 
    129 int deflateParams(z_streamp strm, int level, int strategy)
    130 {
    131 
    132 	return Z_STREAM_ERROR;
    133 }
    134