1/* minigzip.c -- simulate gzip using the zlib compression library
2 * Copyright (C) 1995-1998 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: minigzip.c,v 1.1.1.1 2008/10/15 03:25:54 james26_jang Exp $ */
17
18#include <stdio.h>
19#include "zlib.h"
20
21#ifdef STDC
22#  include <string.h>
23#  include <stdlib.h>
24#else
25   extern void exit  OF((int));
26#endif
27
28#ifdef USE_MMAP
29#  include <sys/types.h>
30#  include <sys/mman.h>
31#  include <sys/stat.h>
32#endif
33
34#if defined(MSDOS) || defined(OS2) || defined(WIN32)
35#  include <fcntl.h>
36#  include <io.h>
37#  define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY)
38#else
39#  define SET_BINARY_MODE(file)
40#endif
41
42#ifdef VMS
43#  define unlink delete
44#  define GZ_SUFFIX "-gz"
45#endif
46#ifdef RISCOS
47#  define unlink remove
48#  define GZ_SUFFIX "-gz"
49#  define fileno(file) file->__file
50#endif
51#if defined(__MWERKS__) && __dest_os != __be_os && __dest_os != __win32_os
52#  include <unix.h> /* for fileno */
53#endif
54
55#ifndef WIN32     /* unlink already in stdio.h for WIN32 */
56  extern int unlink OF((const char *));
57#endif
58
59#ifndef GZ_SUFFIX
60#  define GZ_SUFFIX ".gz"
61#endif
62#define SUFFIX_LEN (sizeof(GZ_SUFFIX)-1)
63
64#define BUFLEN      16384
65#define MAX_NAME_LEN 1024
66
67#ifdef MAXSEG_64K
68#  define local static
69   /* Needed for systems with limitation on stack size. */
70#else
71#  define local
72#endif
73
74char *prog;
75
76void error            OF((const char *msg));
77void gz_compress      OF((FILE   *in, gzFile out));
78#ifdef USE_MMAP
79int  gz_compress_mmap OF((FILE   *in, gzFile out));
80#endif
81void gz_uncompress    OF((gzFile in, FILE   *out));
82void file_compress    OF((char  *file, char *mode));
83void file_uncompress  OF((char  *file));
84int  main             OF((int argc, char *argv[]));
85
86/* ===========================================================================
87 * Display error message and exit
88 */
89void error(msg)
90    const char *msg;
91{
92    fprintf(stderr, "%s: %s\n", prog, msg);
93    exit(1);
94}
95
96/* ===========================================================================
97 * Compress input to output then close both files.
98 */
99
100void gz_compress(in, out)
101    FILE   *in;
102    gzFile out;
103{
104    local char buf[BUFLEN];
105    int len;
106    int err;
107
108#ifdef USE_MMAP
109    /* Try first compressing with mmap. If mmap fails (minigzip used in a
110     * pipe), use the normal fread loop.
111     */
112    if (gz_compress_mmap(in, out) == Z_OK) return;
113#endif
114    for (;;) {
115        len = fread(buf, 1, sizeof(buf), in);
116        if (ferror(in)) {
117            perror("fread");
118            exit(1);
119        }
120        if (len == 0) break;
121
122        if (gzwrite(out, buf, (unsigned)len) != len) error(gzerror(out, &err));
123    }
124    fclose(in);
125    if (gzclose(out) != Z_OK) error("failed gzclose");
126}
127
128#ifdef USE_MMAP     /* MMAP version, Miguel Albrecht <malbrech@eso.org> */
129
130/* Try compressing the input file at once using mmap. Return Z_OK if
131 * if success, Z_ERRNO otherwise.
132 */
133int gz_compress_mmap(in, out)
134    FILE   *in;
135    gzFile out;
136{
137    int len;
138    int err;
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 */
142    struct stat sb;
143
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;
148
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;
152
153    /* Compress the whole file at once: */
154    len = gzwrite(out, (char *)buf, (unsigned)buf_len);
155
156    if (len != (int)buf_len) error(gzerror(out, &err));
157
158    munmap(buf, buf_len);
159    fclose(in);
160    if (gzclose(out) != Z_OK) error("failed gzclose");
161    return Z_OK;
162}
163#endif /* USE_MMAP */
164
165/* ===========================================================================
166 * Uncompress input to output then close both files.
167 */
168void gz_uncompress(in, out)
169    gzFile in;
170    FILE   *out;
171{
172    local char buf[BUFLEN];
173    int len;
174    int err;
175
176    for (;;) {
177        len = gzread(in, buf, sizeof(buf));
178        if (len < 0) error (gzerror(in, &err));
179        if (len == 0) break;
180
181        if ((int)fwrite(buf, 1, (unsigned)len, out) != len) {
182	    error("failed fwrite");
183	}
184    }
185    if (fclose(out)) error("failed fclose");
186
187    if (gzclose(in) != Z_OK) error("failed gzclose");
188}
189
190
191/* ===========================================================================
192 * Compress the given file: create a corresponding .gz file and remove the
193 * original.
194 */
195void file_compress(file, mode)
196    char  *file;
197    char  *mode;
198{
199    local char outfile[MAX_NAME_LEN];
200    FILE  *in;
201    gzFile out;
202
203    strcpy(outfile, file);
204    strcat(outfile, GZ_SUFFIX);
205
206    in = fopen(file, "rb");
207    if (in == NULL) {
208        perror(file);
209        exit(1);
210    }
211    out = gzopen(outfile, mode);
212    if (out == NULL) {
213        fprintf(stderr, "%s: can't gzopen %s\n", prog, outfile);
214        exit(1);
215    }
216    gz_compress(in, out);
217
218    unlink(file);
219}
220
221
222/* ===========================================================================
223 * Uncompress the given file and remove the original.
224 */
225void file_uncompress(file)
226    char  *file;
227{
228    local char buf[MAX_NAME_LEN];
229    char *infile, *outfile;
230    FILE  *out;
231    gzFile in;
232    int len = strlen(file);
233
234    strcpy(buf, file);
235
236    if (len > SUFFIX_LEN && strcmp(file+len-SUFFIX_LEN, GZ_SUFFIX) == 0) {
237        infile = file;
238        outfile = buf;
239        outfile[len-3] = '\0';
240    } else {
241        outfile = file;
242        infile = buf;
243        strcat(infile, GZ_SUFFIX);
244    }
245    in = gzopen(infile, "rb");
246    if (in == NULL) {
247        fprintf(stderr, "%s: can't gzopen %s\n", prog, infile);
248        exit(1);
249    }
250    out = fopen(outfile, "wb");
251    if (out == NULL) {
252        perror(file);
253        exit(1);
254    }
255
256    gz_uncompress(in, out);
257
258    unlink(infile);
259}
260
261
262/* ===========================================================================
263 * Usage:  minigzip [-d] [-f] [-h] [-1 to -9] [files...]
264 *   -d : decompress
265 *   -f : compress with Z_FILTERED
266 *   -h : compress with Z_HUFFMAN_ONLY
267 *   -1 to -9 : compression level
268 */
269
270int main(argc, argv)
271    int argc;
272    char *argv[];
273{
274    int uncompr = 0;
275    gzFile file;
276    char outmode[20];
277
278    strcpy(outmode, "wb6 ");
279
280    prog = argv[0];
281    argc--, argv++;
282
283    while (argc > 0) {
284      if (strcmp(*argv, "-d") == 0)
285	uncompr = 1;
286      else if (strcmp(*argv, "-f") == 0)
287	outmode[3] = 'f';
288      else if (strcmp(*argv, "-h") == 0)
289	outmode[3] = 'h';
290      else if ((*argv)[0] == '-' && (*argv)[1] >= '1' && (*argv)[1] <= '9' &&
291	       (*argv)[2] == 0)
292	outmode[2] = (*argv)[1];
293      else
294	break;
295      argc--, argv++;
296    }
297    if (argc == 0) {
298        SET_BINARY_MODE(stdin);
299        SET_BINARY_MODE(stdout);
300        if (uncompr) {
301            file = gzdopen(fileno(stdin), "rb");
302            if (file == NULL) error("can't gzdopen stdin");
303            gz_uncompress(file, stdout);
304        } else {
305            file = gzdopen(fileno(stdout), outmode);
306            if (file == NULL) error("can't gzdopen stdout");
307            gz_compress(stdin, file);
308        }
309    } else {
310        do {
311            if (uncompr) {
312                file_uncompress(*argv);
313            } else {
314                file_compress(*argv, outmode);
315            }
316        } while (argv++, --argc);
317    }
318    exit(0);
319    return 0; /* to avoid warning */
320}
321