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
4 */
5
6 /*
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
13 * or in pipe mode.
14 */
15
16 /* @(#) $Id$ */
17
18 #include <stdio.h>
19 #include "zlib.h"
20
21 #ifdef STDC
22 # include <string.h>
23 # include <stdlib.h>
24 #endif
25
26 #ifdef USE_MMAP
27 # include <sys/types.h>
28 # include <sys/mman.h>
29 # include <sys/stat.h>
30 #endif
31
32 #if defined(MSDOS) || defined(OS2) || defined(WIN32) || defined(__CYGWIN__)
33 # include <fcntl.h>
34 # include <io.h>
35 # define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY)
36 #else
37 # define SET_BINARY_MODE(file)
38 #endif
39
40 #ifdef VMS
41 # define unlink delete
42 # define GZ_SUFFIX "-gz"
43 #endif
44 #ifdef RISCOS
45 # define unlink remove
46 # define GZ_SUFFIX "-gz"
47 # define fileno(file) file->__file
48 #endif
49 #if defined(__MWERKS__) && __dest_os != __be_os && __dest_os != __win32_os
50 # include <unix.h> /* for fileno */
51 #endif
52
53 #ifndef WIN32 /* unlink already in stdio.h for WIN32 */
54 extern int unlink OF((const char *));
55 #endif
56
57 #ifndef GZ_SUFFIX
58 # define GZ_SUFFIX ".gz"
59 #endif
60 #define SUFFIX_LEN (sizeof(GZ_SUFFIX)-1)
61
62 #define BUFLEN 16384
63 #define MAX_NAME_LEN 1024
64
65 #ifdef MAXSEG_64K
66 # define local static
67 /* Needed for systems with limitation on stack size. */
68 #else
69 # define local
70 #endif
71
72 char *prog;
73
74 void error OF((const char *msg));
75 void gz_compress OF((FILE *in, gzFile out));
76 #ifdef USE_MMAP
77 int gz_compress_mmap OF((FILE *in, gzFile out));
78 #endif
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[]));
83
84 /* ===========================================================================
85 * Display error message and exit
86 */
error(msg)87 void error(msg)
88 const char *msg;
89 {
90 fprintf(stderr, "%s: %s\n", prog, msg);
91 exit(1);
92 }
93
94 /* ===========================================================================
95 * Compress input to output then close both files.
96 */
97
gz_compress(in,out)98 void gz_compress(in, out)
99 FILE *in;
100 gzFile out;
101 {
102 local char buf[BUFLEN];
103 int len;
104 int err;
105
106 #ifdef USE_MMAP
107 /* Try first compressing with mmap. If mmap fails (minigzip used in a
108 * pipe), use the normal fread loop.
109 */
110 if (gz_compress_mmap(in, out) == Z_OK) return;
111 #endif
112 for (;;) {
113 len = (int)fread(buf, 1, sizeof(buf), in);
114 if (ferror(in)) {
115 perror("fread");
116 exit(1);
117 }
118 if (len == 0) break;
119
120 if (gzwrite(out, buf, (unsigned)len) != len) error(gzerror(out, &err));
121 }
122 fclose(in);
123 if (gzclose(out) != Z_OK) error("failed gzclose");
124 }
125
126 #ifdef USE_MMAP /* MMAP version, Miguel Albrecht <malbrech@eso.org> */
127
128 /* Try compressing the input file at once using mmap. Return Z_OK if
129 * if success, Z_ERRNO otherwise.
130 */
gz_compress_mmap(in,out)131 int gz_compress_mmap(in, out)
132 FILE *in;
133 gzFile out;
134 {
135 int len;
136 int err;
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 */
140 struct stat sb;
141
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;
146
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;
150
151 /* Compress the whole file at once: */
152 len = gzwrite(out, (char *)buf, (unsigned)buf_len);
153
154 if (len != (int)buf_len) error(gzerror(out, &err));
155
156 munmap(buf, buf_len);
157 fclose(in);
158 if (gzclose(out) != Z_OK) error("failed gzclose");
159 return Z_OK;
160 }
161 #endif /* USE_MMAP */
162
163 /* ===========================================================================
164 * Uncompress input to output then close both files.
165 */
gz_uncompress(in,out)166 void gz_uncompress(in, out)
167 gzFile in;
168 FILE *out;
169 {
170 local char buf[BUFLEN];
171 int len;
172 int err;
173
174 for (;;) {
175 len = gzread(in, buf, sizeof(buf));
176 if (len < 0) error (gzerror(in, &err));
177 if (len == 0) break;
178
179 if ((int)fwrite(buf, 1, (unsigned)len, out) != len) {
180 error("failed fwrite");
181 }
182 }
183 if (fclose(out)) error("failed fclose");
184
185 if (gzclose(in) != Z_OK) error("failed gzclose");
186 }
187
188
189 /* ===========================================================================
190 * Compress the given file: create a corresponding .gz file and remove the
191 * original.
192 */
file_compress(file,mode)193 void file_compress(file, mode)
194 char *file;
195 char *mode;
196 {
197 local char outfile[MAX_NAME_LEN];
198 FILE *in;
199 gzFile out;
200
201 strcpy(outfile, file);
202 strcat(outfile, GZ_SUFFIX);
203
204 in = fopen(file, "rb");
205 if (in == NULL) {
206 perror(file);
207 exit(1);
208 }
209 out = gzopen(outfile, mode);
210 if (out == NULL) {
211 fprintf(stderr, "%s: can't gzopen %s\n", prog, outfile);
212 exit(1);
213 }
214 gz_compress(in, out);
215
216 unlink(file);
217 }
218
219
220 /* ===========================================================================
221 * Uncompress the given file and remove the original.
222 */
file_uncompress(file)223 void file_uncompress(file)
224 char *file;
225 {
226 local char buf[MAX_NAME_LEN];
227 char *infile, *outfile;
228 FILE *out;
229 gzFile in;
230 uInt len = (uInt)strlen(file);
231
232 strcpy(buf, file);
233
234 if (len > SUFFIX_LEN && strcmp(file+len-SUFFIX_LEN, GZ_SUFFIX) == 0) {
235 infile = file;
236 outfile = buf;
237 outfile[len-3] = '\0';
238 } else {
239 outfile = file;
240 infile = buf;
241 strcat(infile, GZ_SUFFIX);
242 }
243 in = gzopen(infile, "rb");
244 if (in == NULL) {
245 fprintf(stderr, "%s: can't gzopen %s\n", prog, infile);
246 exit(1);
247 }
248 out = fopen(outfile, "wb");
249 if (out == NULL) {
250 perror(file);
251 exit(1);
252 }
253
254 gz_uncompress(in, out);
255
256 unlink(infile);
257 }
258
259
260 /* ===========================================================================
261 * Usage: minigzip [-d] [-f] [-h] [-r] [-1 to -9] [files...]
262 * -d : decompress
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
267 */
268
main(argc,argv)269 int main(argc, argv)
270 int argc;
271 char *argv[];
272 {
273 int uncompr = 0;
274 gzFile file;
275 char outmode[20];
276
277 strcpy(outmode, "wb6 ");
278
279 prog = argv[0];
280 argc--, argv++;
281
282 while (argc > 0) {
283 if (strcmp(*argv, "-d") == 0)
284 uncompr = 1;
285 else if (strcmp(*argv, "-f") == 0)
286 outmode[3] = 'f';
287 else if (strcmp(*argv, "-h") == 0)
288 outmode[3] = 'h';
289 else if (strcmp(*argv, "-r") == 0)
290 outmode[3] = 'R';
291 else if ((*argv)[0] == '-' && (*argv)[1] >= '1' && (*argv)[1] <= '9' &&
292 (*argv)[2] == 0)
293 outmode[2] = (*argv)[1];
294 else
295 break;
296 argc--, argv++;
297 }
298 if (outmode[3] == ' ')
299 outmode[3] = 0;
300 if (argc == 0) {
301 SET_BINARY_MODE(stdin);
302 SET_BINARY_MODE(stdout);
303 if (uncompr) {
304 file = gzdopen(fileno(stdin), "rb");
305 if (file == NULL) error("can't gzdopen stdin");
306 gz_uncompress(file, stdout);
307 } else {
308 file = gzdopen(fileno(stdout), outmode);
309 if (file == NULL) error("can't gzdopen stdout");
310 gz_compress(stdin, file);
311 }
312 } else {
313 do {
314 if (uncompr) {
315 file_uncompress(*argv);
316 } else {
317 file_compress(*argv, outmode);
318 }
319 } while (argv++, --argc);
320 }
321 return 0;
322 }
323