1
/* minigzip.c -- simulate gzip using the zlib compression library
2
* Copyright (C) 1995-2002 Jean-loup Gailly.
3
* For conditions of distribution and use, see copyright notice in zlib.h
7
* minigzip is a minimal implementation of the gzip utility. This is
8
* only an example of using zlib and isn't meant to replace the
9
* full-featured gzip. No attempt is made to deal with file systems
10
* limiting names to 14 or 8+3 characters, etc... Error checking is
11
* very limited. So use minigzip only for testing; use gzip for the
12
* real thing. On MSDOS, use only on file names without extension
25
extern void exit OF((int));
29
# include <sys/types.h>
30
# include <sys/mman.h>
31
# include <sys/stat.h>
34
#if defined(MSDOS) || defined(OS2) || defined(WIN32) || defined(__CYGWIN__)
37
# define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY)
39
# define SET_BINARY_MODE(file)
43
# define unlink delete
44
# define GZ_SUFFIX "-gz"
47
# define unlink remove
48
# define GZ_SUFFIX "-gz"
49
# define fileno(file) file->__file
51
#if defined(__MWERKS__) && __dest_os != __be_os && __dest_os != __win32_os
52
# include <unix.h> /* for fileno */
55
#ifndef WIN32 /* unlink already in stdio.h for WIN32 */
56
extern int unlink OF((const char *));
60
# define GZ_SUFFIX ".gz"
62
#define SUFFIX_LEN (sizeof(GZ_SUFFIX)-1)
65
#define MAX_NAME_LEN 1024
69
/* Needed for systems with limitation on stack size. */
76
void error OF((const char *msg));
77
void gz_compress OF((FILE *in, gzFile out));
79
int gz_compress_mmap OF((FILE *in, gzFile out));
81
void gz_uncompress OF((gzFile in, FILE *out));
82
void file_compress OF((char *file, char *mode));
83
void file_uncompress OF((char *file));
84
int main OF((int argc, char *argv[]));
86
/* ===========================================================================
87
* Display error message and exit
92
fprintf(stderr, "%s: %s\n", prog, msg);
96
/* ===========================================================================
97
* Compress input to output then close both files.
100
void gz_compress(in, out)
104
local char buf[BUFLEN];
109
/* Try first compressing with mmap. If mmap fails (minigzip used in a
110
* pipe), use the normal fread loop.
112
if (gz_compress_mmap(in, out) == Z_OK) return;
115
len = (int)fread(buf, 1, sizeof(buf), in);
122
if (gzwrite(out, buf, (unsigned)len) != len) error(gzerror(out, &err));
125
if (gzclose(out) != Z_OK) error("failed gzclose");
128
#ifdef USE_MMAP /* MMAP version, Miguel Albrecht <malbrech@eso.org> */
130
/* Try compressing the input file at once using mmap. Return Z_OK if
131
* if success, Z_ERRNO otherwise.
133
int gz_compress_mmap(in, out)
139
int ifd = fileno(in);
140
caddr_t buf; /* mmap'ed buffer for the entire input file */
141
off_t buf_len; /* length of the input file */
144
/* Determine the size of the file, needed for mmap: */
145
if (fstat(ifd, &sb) < 0) return Z_ERRNO;
146
buf_len = sb.st_size;
147
if (buf_len <= 0) return Z_ERRNO;
149
/* Now do the actual mmap: */
150
buf = mmap((caddr_t) 0, buf_len, PROT_READ, MAP_SHARED, ifd, (off_t)0);
151
if (buf == (caddr_t)(-1)) return Z_ERRNO;
153
/* Compress the whole file at once: */
154
len = gzwrite(out, (char *)buf, (unsigned)buf_len);
156
if (len != (int)buf_len) error(gzerror(out, &err));
158
munmap(buf, buf_len);
160
if (gzclose(out) != Z_OK) error("failed gzclose");
163
#endif /* USE_MMAP */
165
/* ===========================================================================
166
* Uncompress input to output then close both files.
168
void gz_uncompress(in, out)
172
local char buf[BUFLEN];
177
len = gzread(in, buf, sizeof(buf));
178
if (len < 0) error (gzerror(in, &err));
181
if ((int)fwrite(buf, 1, (unsigned)len, out) != len) {
182
error("failed fwrite");
185
if (fclose(out)) error("failed fclose");
187
if (gzclose(in) != Z_OK) error("failed gzclose");
191
/* ===========================================================================
192
* Compress the given file: create a corresponding .gz file and remove the
195
void file_compress(file, mode)
199
local char outfile[MAX_NAME_LEN];
203
strcpy(outfile, file);
204
strcat(outfile, GZ_SUFFIX);
206
in = fopen(file, "rb");
211
out = gzopen(outfile, mode);
213
fprintf(stderr, "%s: can't gzopen %s\n", prog, outfile);
216
gz_compress(in, out);
222
/* ===========================================================================
223
* Uncompress the given file and remove the original.
225
void file_uncompress(file)
228
local char buf[MAX_NAME_LEN];
229
char *infile, *outfile;
232
uInt len = (uInt)strlen(file);
236
if (len > SUFFIX_LEN && strcmp(file+len-SUFFIX_LEN, GZ_SUFFIX) == 0) {
239
outfile[len-3] = '\0';
243
strcat(infile, GZ_SUFFIX);
245
in = gzopen(infile, "rb");
247
fprintf(stderr, "%s: can't gzopen %s\n", prog, infile);
250
out = fopen(outfile, "wb");
256
gz_uncompress(in, out);
262
/* ===========================================================================
263
* Usage: minigzip [-d] [-f] [-h] [-r] [-1 to -9] [files...]
265
* -f : compress with Z_FILTERED
266
* -h : compress with Z_HUFFMAN_ONLY
267
* -r : compress with Z_RLE
268
* -1 to -9 : compression level
279
strcpy(outmode, "wb6 ");
285
if (strcmp(*argv, "-d") == 0)
287
else if (strcmp(*argv, "-f") == 0)
289
else if (strcmp(*argv, "-h") == 0)
291
else if (strcmp(*argv, "-r") == 0)
293
else if ((*argv)[0] == '-' && (*argv)[1] >= '1' && (*argv)[1] <= '9' &&
295
outmode[2] = (*argv)[1];
301
SET_BINARY_MODE(stdin);
302
SET_BINARY_MODE(stdout);
304
file = gzdopen(fileno(stdin), "rb");
305
if (file == NULL) error("can't gzdopen stdin");
306
gz_uncompress(file, stdout);
308
file = gzdopen(fileno(stdout), outmode);
309
if (file == NULL) error("can't gzdopen stdout");
310
gz_compress(stdin, file);
315
file_uncompress(*argv);
317
file_compress(*argv, outmode);
319
} while (argv++, --argc);