1 /* minigzip.c -- simulate gzip using the zlib compression library
2 * Copyright (C) 1995-2005 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__)
35 # define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY)
37 # define SET_BINARY_MODE(file)
41 # define unlink delete
42 # define GZ_SUFFIX "-gz"
45 # define unlink remove
46 # define GZ_SUFFIX "-gz"
47 # define fileno(file) file->__file
49 #if defined(__MWERKS__) && __dest_os != __be_os && __dest_os != __win32_os
50 # include <unix.h> /* for fileno */
53 #ifndef WIN32 /* unlink already in stdio.h for WIN32 */
54 extern int unlink OF((const char *));
58 # define GZ_SUFFIX ".gz"
60 #define SUFFIX_LEN (sizeof(GZ_SUFFIX)-1)
63 #define MAX_NAME_LEN 1024
67 /* Needed for systems with limitation on stack size. */
74 void error OF((const char *msg));
75 void gz_compress OF((FILE *in, gzFile out));
77 int gz_compress_mmap OF((FILE *in, gzFile out));
79 void gz_uncompress OF((gzFile in, FILE *out));
80 void file_compress OF((char *file, char *mode));
81 void file_uncompress OF((char *file));
82 int main OF((int argc, char *argv[]));
84 /* ===========================================================================
85 * Display error message and exit
90 fprintf(stderr, "%s: %s\n", prog, msg);
94 /* ===========================================================================
95 * Compress input to output then close both files.
98 void gz_compress(in, out)
102 local char buf[BUFLEN];
107 /* Try first compressing with mmap. If mmap fails (minigzip used in a
108 * pipe), use the normal fread loop.
110 if (gz_compress_mmap(in, out) == Z_OK) return;
113 len = (int)fread(buf, 1, sizeof(buf), in);
120 if (gzwrite(out, buf, (unsigned)len) != len) error(gzerror(out, &err));
123 if (gzclose(out) != Z_OK) error("failed gzclose");
126 #ifdef USE_MMAP /* MMAP version, Miguel Albrecht <malbrech@eso.org> */
128 /* Try compressing the input file at once using mmap. Return Z_OK if
129 * if success, Z_ERRNO otherwise.
131 int gz_compress_mmap(in, out)
137 int ifd = fileno(in);
138 caddr_t buf; /* mmap'ed buffer for the entire input file */
139 off_t buf_len; /* length of the input file */
142 /* Determine the size of the file, needed for mmap: */
143 if (fstat(ifd, &sb) < 0) return Z_ERRNO;
144 buf_len = sb.st_size;
145 if (buf_len <= 0) return Z_ERRNO;
147 /* Now do the actual mmap: */
148 buf = mmap((caddr_t) 0, buf_len, PROT_READ, MAP_SHARED, ifd, (off_t)0);
149 if (buf == (caddr_t)(-1)) return Z_ERRNO;
151 /* Compress the whole file at once: */
152 len = gzwrite(out, (char *)buf, (unsigned)buf_len);
154 if (len != (int)buf_len) error(gzerror(out, &err));
156 munmap(buf, buf_len);
158 if (gzclose(out) != Z_OK) error("failed gzclose");
161 #endif /* USE_MMAP */
163 /* ===========================================================================
164 * Uncompress input to output then close both files.
166 void gz_uncompress(in, out)
170 local char buf[BUFLEN];
175 len = gzread(in, buf, sizeof(buf));
176 if (len < 0) error (gzerror(in, &err));
179 if ((int)fwrite(buf, 1, (unsigned)len, out) != len) {
180 error("failed fwrite");
183 if (fclose(out)) error("failed fclose");
185 if (gzclose(in) != Z_OK) error("failed gzclose");
189 /* ===========================================================================
190 * Compress the given file: create a corresponding .gz file and remove the
193 void file_compress(file, mode)
197 local char outfile[MAX_NAME_LEN];
201 strcpy(outfile, file);
202 strcat(outfile, GZ_SUFFIX);
204 in = fopen(file, "rb");
209 out = gzopen(outfile, mode);
211 fprintf(stderr, "%s: can't gzopen %s\n", prog, outfile);
214 gz_compress(in, out);
220 /* ===========================================================================
221 * Uncompress the given file and remove the original.
223 void file_uncompress(file)
226 local char buf[MAX_NAME_LEN];
227 char *infile, *outfile;
230 uInt len = (uInt)strlen(file);
234 if (len > SUFFIX_LEN && strcmp(file+len-SUFFIX_LEN, GZ_SUFFIX) == 0) {
237 outfile[len-3] = '\0';
241 strcat(infile, GZ_SUFFIX);
243 in = gzopen(infile, "rb");
245 fprintf(stderr, "%s: can't gzopen %s\n", prog, infile);
248 out = fopen(outfile, "wb");
254 gz_uncompress(in, out);
260 /* ===========================================================================
261 * Usage: minigzip [-d] [-f] [-h] [-r] [-1 to -9] [files...]
263 * -f : compress with Z_FILTERED
264 * -h : compress with Z_HUFFMAN_ONLY
265 * -r : compress with Z_RLE
266 * -1 to -9 : compression level
277 strcpy(outmode, "wb6 ");
283 if (strcmp(*argv, "-d") == 0)
285 else if (strcmp(*argv, "-f") == 0)
287 else if (strcmp(*argv, "-h") == 0)
289 else if (strcmp(*argv, "-r") == 0)
291 else if ((*argv)[0] == '-' && (*argv)[1] >= '1' && (*argv)[1] <= '9' &&
293 outmode[2] = (*argv)[1];
298 if (outmode[3] == ' ')
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);