1 /* minigzip.c -- simulate gzip using the zlib compression library
2 * Copyright (C) 1995-2006, 2010 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
27 # include <sys/types.h>
28 # include <sys/mman.h>
29 # include <sys/stat.h>
32 #if defined(MSDOS) || defined(OS2) || defined(WIN32) || defined(__CYGWIN__)
38 # define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY)
40 # define SET_BINARY_MODE(file)
44 # define unlink delete
45 # define GZ_SUFFIX "-gz"
48 # define unlink remove
49 # define GZ_SUFFIX "-gz"
50 # define fileno(file) file->__file
52 #if defined(__MWERKS__) && __dest_os != __be_os && __dest_os != __win32_os
53 # include <unix.h> /* for fileno */
56 #if !defined(Z_HAVE_UNISTD_H) && !defined(_LARGEFILE64_SOURCE)
57 #ifndef WIN32 /* unlink already in stdio.h for WIN32 */
58 extern int unlink
OF((const char *));
64 # define perror(s) pwinerror(s)
66 /* Map the Windows error number in ERROR to a locale-dependent error
67 message string and return a pointer to it. Typically, the values
68 for ERROR come from GetLastError.
70 The string pointed to shall not be modified by the application,
71 but may be overwritten by a subsequent call to strwinerror
73 The strwinerror function does not change the current setting
76 static char *strwinerror (error
)
79 static char buf
[1024];
82 DWORD lasterr
= GetLastError();
83 DWORD chars
= FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM
84 | FORMAT_MESSAGE_ALLOCATE_BUFFER
,
87 0, /* Default language */
92 /* If there is an \r\n appended, zap it. */
94 && msgbuf
[chars
- 2] == '\r' && msgbuf
[chars
- 1] == '\n') {
99 if (chars
> sizeof (buf
) - 1) {
100 chars
= sizeof (buf
) - 1;
104 wcstombs(buf
, msgbuf
, chars
+ 1);
108 sprintf(buf
, "unknown win32 error (%ld)", error
);
111 SetLastError(lasterr
);
115 static void pwinerror (s
)
119 fprintf(stderr
, "%s: %s\n", s
, strwinerror(GetLastError ()));
121 fprintf(stderr
, "%s\n", strwinerror(GetLastError ()));
124 #endif /* UNDER_CE */
127 # define GZ_SUFFIX ".gz"
129 #define SUFFIX_LEN (sizeof(GZ_SUFFIX)-1)
132 #define MAX_NAME_LEN 1024
135 # define local static
136 /* Needed for systems with limitation on stack size. */
143 void error
OF((const char *msg
));
144 void gz_compress
OF((FILE *in
, gzFile out
));
146 int gz_compress_mmap
OF((FILE *in
, gzFile out
));
148 void gz_uncompress
OF((gzFile in
, FILE *out
));
149 void file_compress
OF((char *file
, char *mode
));
150 void file_uncompress
OF((char *file
));
151 int main
OF((int argc
, char *argv
[]));
153 /* ===========================================================================
154 * Display error message and exit
159 fprintf(stderr
, "%s: %s\n", prog
, msg
);
163 /* ===========================================================================
164 * Compress input to output then close both files.
167 void gz_compress(in
, out
)
171 local
char buf
[BUFLEN
];
176 /* Try first compressing with mmap. If mmap fails (minigzip used in a
177 * pipe), use the normal fread loop.
179 if (gz_compress_mmap(in
, out
) == Z_OK
) return;
182 len
= (int)fread(buf
, 1, sizeof(buf
), in
);
189 if (gzwrite(out
, buf
, (unsigned)len
) != len
) error(gzerror(out
, &err
));
192 if (gzclose(out
) != Z_OK
) error("failed gzclose");
195 #ifdef USE_MMAP /* MMAP version, Miguel Albrecht <malbrech@eso.org> */
197 /* Try compressing the input file at once using mmap. Return Z_OK if
198 * if success, Z_ERRNO otherwise.
200 int gz_compress_mmap(in
, out
)
206 int ifd
= fileno(in
);
207 caddr_t buf
; /* mmap'ed buffer for the entire input file */
208 off_t buf_len
; /* length of the input file */
211 /* Determine the size of the file, needed for mmap: */
212 if (fstat(ifd
, &sb
) < 0) return Z_ERRNO
;
213 buf_len
= sb
.st_size
;
214 if (buf_len
<= 0) return Z_ERRNO
;
216 /* Now do the actual mmap: */
217 buf
= mmap((caddr_t
) 0, buf_len
, PROT_READ
, MAP_SHARED
, ifd
, (off_t
)0);
218 if (buf
== (caddr_t
)(-1)) return Z_ERRNO
;
220 /* Compress the whole file at once: */
221 len
= gzwrite(out
, (char *)buf
, (unsigned)buf_len
);
223 if (len
!= (int)buf_len
) error(gzerror(out
, &err
));
225 munmap(buf
, buf_len
);
227 if (gzclose(out
) != Z_OK
) error("failed gzclose");
230 #endif /* USE_MMAP */
232 /* ===========================================================================
233 * Uncompress input to output then close both files.
235 void gz_uncompress(in
, out
)
239 local
char buf
[BUFLEN
];
244 len
= gzread(in
, buf
, sizeof(buf
));
245 if (len
< 0) error (gzerror(in
, &err
));
248 if ((int)fwrite(buf
, 1, (unsigned)len
, out
) != len
) {
249 error("failed fwrite");
252 if (fclose(out
)) error("failed fclose");
254 if (gzclose(in
) != Z_OK
) error("failed gzclose");
258 /* ===========================================================================
259 * Compress the given file: create a corresponding .gz file and remove the
262 void file_compress(file
, mode
)
266 local
char outfile
[MAX_NAME_LEN
];
270 if (strlen(file
) + strlen(GZ_SUFFIX
) >= sizeof(outfile
)) {
271 fprintf(stderr
, "%s: filename too long\n", prog
);
275 strcpy(outfile
, file
);
276 strcat(outfile
, GZ_SUFFIX
);
278 in
= fopen(file
, "rb");
283 out
= gzopen(outfile
, mode
);
285 fprintf(stderr
, "%s: can't gzopen %s\n", prog
, outfile
);
288 gz_compress(in
, out
);
294 /* ===========================================================================
295 * Uncompress the given file and remove the original.
297 void file_uncompress(file
)
300 local
char buf
[MAX_NAME_LEN
];
301 char *infile
, *outfile
;
304 size_t len
= strlen(file
);
306 if (len
+ strlen(GZ_SUFFIX
) >= sizeof(buf
)) {
307 fprintf(stderr
, "%s: filename too long\n", prog
);
313 if (len
> SUFFIX_LEN
&& strcmp(file
+len
-SUFFIX_LEN
, GZ_SUFFIX
) == 0) {
316 outfile
[len
-3] = '\0';
320 strcat(infile
, GZ_SUFFIX
);
322 in
= gzopen(infile
, "rb");
324 fprintf(stderr
, "%s: can't gzopen %s\n", prog
, infile
);
327 out
= fopen(outfile
, "wb");
333 gz_uncompress(in
, out
);
339 /* ===========================================================================
340 * Usage: minigzip [-c] [-d] [-f] [-h] [-r] [-1 to -9] [files...]
341 * -c : write to standard output
343 * -f : compress with Z_FILTERED
344 * -h : compress with Z_HUFFMAN_ONLY
345 * -r : compress with Z_RLE
346 * -1 to -9 : compression level
356 char *bname
, outmode
[20];
358 strcpy(outmode
, "wb6 ");
361 bname
= strrchr(argv
[0], '/');
368 if (!strcmp(bname
, "gunzip"))
370 else if (!strcmp(bname
, "zcat"))
371 copyout
= uncompr
= 1;
374 if (strcmp(*argv
, "-c") == 0)
376 else if (strcmp(*argv
, "-d") == 0)
378 else if (strcmp(*argv
, "-f") == 0)
380 else if (strcmp(*argv
, "-h") == 0)
382 else if (strcmp(*argv
, "-r") == 0)
384 else if ((*argv
)[0] == '-' && (*argv
)[1] >= '1' && (*argv
)[1] <= '9' &&
386 outmode
[2] = (*argv
)[1];
391 if (outmode
[3] == ' ')
394 SET_BINARY_MODE(stdin
);
395 SET_BINARY_MODE(stdout
);
397 file
= gzdopen(fileno(stdin
), "rb");
398 if (file
== NULL
) error("can't gzdopen stdin");
399 gz_uncompress(file
, stdout
);
401 file
= gzdopen(fileno(stdout
), outmode
);
402 if (file
== NULL
) error("can't gzdopen stdout");
403 gz_compress(stdin
, file
);
407 SET_BINARY_MODE(stdout
);
412 file
= gzopen(*argv
, "rb");
414 fprintf(stderr
, "%s: can't gzopen %s\n", prog
, *argv
);
416 gz_uncompress(file
, stdout
);
418 file_uncompress(*argv
);
422 FILE * in
= fopen(*argv
, "rb");
427 file
= gzdopen(fileno(stdout
), outmode
);
428 if (file
== NULL
) error("can't gzdopen stdout");
430 gz_compress(in
, file
);
434 file_compress(*argv
, outmode
);
437 } while (argv
++, --argc
);