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/* minigzip.c -- simulate gzip using the zlib compression library
* Copyright (C) 1995-1996 Jean-loup Gailly.
* For conditions of distribution and use, see copyright notice in zlib.h
*/
/*
* minigzip is a minimal implementation of the gzip utility. This is
* only an example of using zlib and isn't meant to replace the
* full-featured gzip. No attempt is made to deal with file systems
* limiting names to 14 or 8+3 characters, etc... Error checking is
* very limited. So use minigzip only for testing; use gzip for the
* real thing. On MSDOS, use only on file names without extension
* or in pipe mode.
*/
/* $Id: minigzip.c,v 1.10 1996/07/24 13:41:04 me Exp $ */
#include <stdio.h>
#include "zlib.h"
#ifdef STDC
# include <string.h>
# include <stdlib.h>
#else
extern void exit OF((int));
#endif
#if defined(MSDOS) || defined(OS2) || defined(WIN32)
# include <fcntl.h>
# include <io.h>
# define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY)
#else
# define SET_BINARY_MODE(file)
#endif
#ifdef VMS
# define unlink delete
# define GZ_SUFFIX "-gz"
#endif
#ifdef RISCOS
# define unlink remove
# define GZ_SUFFIX "-gz"
# define fileno(file) file->__file
#endif
#ifndef GZ_SUFFIX
# define GZ_SUFFIX ".gz"
#endif
#define SUFFIX_LEN sizeof(GZ_SUFFIX)
extern int unlink OF((const char *));
#define BUFLEN 4096
#define MAX_NAME_LEN 1024
#define local static
/* For MSDOS and other systems with limitation on stack size. For Unix,
#define local
works also.
*/
char *prog;
void error OF((const char *msg));
void gz_compress OF((FILE *in, gzFile out));
void gz_uncompress OF((gzFile in, FILE *out));
void file_compress OF((char *file));
void file_uncompress OF((char *file));
int main OF((int argc, char *argv[]));
/* ===========================================================================
* Display error message and exit
*/
void error(msg)
const char *msg;
{
fprintf(stderr, "%s: %s\n", prog, msg);
exit(1);
}
/* ===========================================================================
* Compress input to output then close both files.
*/
void gz_compress(in, out)
FILE *in;
gzFile out;
{
local char buf[BUFLEN];
int len;
int err;
for (;;) {
len = fread(buf, 1, sizeof(buf), in);
if (ferror(in)) {
perror("fread");
exit(1);
}
if (len == 0) break;
if (gzwrite(out, buf, (unsigned)len) != len) error(gzerror(out, &err));
}
fclose(in);
if (gzclose(out) != Z_OK) error("failed gzclose");
}
/* ===========================================================================
* Uncompress input to output then close both files.
*/
void gz_uncompress(in, out)
gzFile in;
FILE *out;
{
local char buf[BUFLEN];
int len;
int err;
for (;;) {
len = gzread(in, buf, sizeof(buf));
if (len < 0) error (gzerror(in, &err));
if (len == 0) break;
if ((int)fwrite(buf, 1, (unsigned)len, out) != len) {
error("failed fwrite");
}
}
if (fclose(out)) error("failed fclose");
if (gzclose(in) != Z_OK) error("failed gzclose");
}
/* ===========================================================================
* Compress the given file: create a corresponding .gz file and remove the
* original.
*/
void file_compress(file)
char *file;
{
local char outfile[MAX_NAME_LEN];
FILE *in;
gzFile out;
strcpy(outfile, file);
strcat(outfile, GZ_SUFFIX);
in = fopen(file, "rb");
if (in == NULL) {
perror(file);
exit(1);
}
out = gzopen(outfile, "wb"); /* use "wb9" for maximal compression */
if (out == NULL) {
fprintf(stderr, "%s: can't gzopen %s\n", prog, outfile);
exit(1);
}
gz_compress(in, out);
unlink(file);
}
/* ===========================================================================
* Uncompress the given file and remove the original.
*/
void file_uncompress(file)
char *file;
{
local char buf[MAX_NAME_LEN];
char *infile, *outfile;
FILE *out;
gzFile in;
int len = strlen(file);
strcpy(buf, file);
if (len > SUFFIX_LEN && strcmp(file+len-SUFFIX_LEN, GZ_SUFFIX) == 0) {
infile = file;
outfile = buf;
outfile[len-3] = '\0';
} else {
outfile = file;
infile = buf;
strcat(infile, GZ_SUFFIX);
}
in = gzopen(infile, "rb");
if (in == NULL) {
fprintf(stderr, "%s: can't gzopen %s\n", prog, infile);
exit(1);
}
out = fopen(outfile, "wb");
if (out == NULL) {
perror(file);
exit(1);
}
gz_uncompress(in, out);
unlink(infile);
}
/* ===========================================================================
* Usage: minigzip [-d] [files...]
*/
int main(argc, argv)
int argc;
char *argv[];
{
int uncompr = 0;
gzFile file;
prog = argv[0];
argc--, argv++;
if (argc > 0) {
uncompr = (strcmp(*argv, "-d") == 0);
if (uncompr) {
argc--, argv++;
}
}
if (argc == 0) {
SET_BINARY_MODE(stdin);
SET_BINARY_MODE(stdout);
if (uncompr) {
file = gzdopen(fileno(stdin), "rb");
if (file == NULL) error("can't gzdopen stdin");
gz_uncompress(file, stdout);
} else {
file = gzdopen(fileno(stdout), "wb"); /* "wb9" for max compr. */
if (file == NULL) error("can't gzdopen stdout");
gz_compress(stdin, file);
}
} else {
do {
if (uncompr) {
file_uncompress(*argv);
} else {
file_compress(*argv);
}
} while (argv++, --argc);
}
exit(0);
return 0; /* to avoid warning */
}
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