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);