1/* zpipe.c: example of proper use of zlib's inflate() and deflate()
2   Not copyrighted -- provided to the public domain
3   Version 1.4  11 December 2005  Mark Adler */
4
5/* Version history:
6   1.0  30 Oct 2004  First version
7   1.1   8 Nov 2004  Add void casting for unused return values
8                     Use switch statement for inflate() return values
9   1.2   9 Nov 2004  Add assertions to document zlib guarantees
10   1.3   6 Apr 2005  Remove incorrect assertion in inf()
11   1.4  11 Dec 2005  Add hack to avoid MSDOS end-of-line conversions
12                     Avoid some compiler warnings for input and output buffers
13 */
14
15#include <stdio.h>
16#include <string.h>
17#include <assert.h>
18#include "zlib.h"
19
20#if defined(MSDOS) || defined(OS2) || defined(WIN32) || defined(__CYGWIN__)
21#  include <fcntl.h>
22#  include <io.h>
23#  define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY)
24#else
25#  define SET_BINARY_MODE(file)
26#endif
27
28#define CHUNK 16384
29
30/* Compress from file source to file dest until EOF on source.
31   def() returns Z_OK on success, Z_MEM_ERROR if memory could not be
32   allocated for processing, Z_STREAM_ERROR if an invalid compression
33   level is supplied, Z_VERSION_ERROR if the version of zlib.h and the
34   version of the library linked do not match, or Z_ERRNO if there is
35   an error reading or writing the files. */
36int def(FILE *source, FILE *dest, int level)
37{
38    int ret, flush;
39    unsigned have;
40    z_stream strm;
41    unsigned char in[CHUNK];
42    unsigned char out[CHUNK];
43
44    /* allocate deflate state */
45    strm.zalloc = Z_NULL;
46    strm.zfree = Z_NULL;
47    strm.opaque = Z_NULL;
48    ret = deflateInit(&strm, level);
49    if (ret != Z_OK)
50        return ret;
51
52    /* compress until end of file */
53    do {
54        strm.avail_in = fread(in, 1, CHUNK, source);
55        if (ferror(source)) {
56            (void)deflateEnd(&strm);
57            return Z_ERRNO;
58        }
59        flush = feof(source) ? Z_FINISH : Z_NO_FLUSH;
60        strm.next_in = in;
61
62        /* run deflate() on input until output buffer not full, finish
63           compression if all of source has been read in */
64        do {
65            strm.avail_out = CHUNK;
66            strm.next_out = out;
67            ret = deflate(&strm, flush);    /* no bad return value */
68            assert(ret != Z_STREAM_ERROR);  /* state not clobbered */
69            have = CHUNK - strm.avail_out;
70            if (fwrite(out, 1, have, dest) != have || ferror(dest)) {
71                (void)deflateEnd(&strm);
72                return Z_ERRNO;
73            }
74        } while (strm.avail_out == 0);
75        assert(strm.avail_in == 0);     /* all input will be used */
76
77        /* done when last data in file processed */
78    } while (flush != Z_FINISH);
79    assert(ret == Z_STREAM_END);        /* stream will be complete */
80
81    /* clean up and return */
82    (void)deflateEnd(&strm);
83    return Z_OK;
84}
85
86/* Decompress from file source to file dest until stream ends or EOF.
87   inf() returns Z_OK on success, Z_MEM_ERROR if memory could not be
88   allocated for processing, Z_DATA_ERROR if the deflate data is
89   invalid or incomplete, Z_VERSION_ERROR if the version of zlib.h and
90   the version of the library linked do not match, or Z_ERRNO if there
91   is an error reading or writing the files. */
92int inf(FILE *source, FILE *dest)
93{
94    int ret;
95    unsigned have;
96    z_stream strm;
97    unsigned char in[CHUNK];
98    unsigned char out[CHUNK];
99
100    /* allocate inflate state */
101    strm.zalloc = Z_NULL;
102    strm.zfree = Z_NULL;
103    strm.opaque = Z_NULL;
104    strm.avail_in = 0;
105    strm.next_in = Z_NULL;
106    ret = inflateInit(&strm);
107    if (ret != Z_OK)
108        return ret;
109
110    /* decompress until deflate stream ends or end of file */
111    do {
112        strm.avail_in = fread(in, 1, CHUNK, source);
113        if (ferror(source)) {
114            (void)inflateEnd(&strm);
115            return Z_ERRNO;
116        }
117        if (strm.avail_in == 0)
118            break;
119        strm.next_in = in;
120
121        /* run inflate() on input until output buffer not full */
122        do {
123            strm.avail_out = CHUNK;
124            strm.next_out = out;
125            ret = inflate(&strm, Z_NO_FLUSH);
126            assert(ret != Z_STREAM_ERROR);  /* state not clobbered */
127            switch (ret) {
128            case Z_NEED_DICT:
129                ret = Z_DATA_ERROR;     /* and fall through */
130            case Z_DATA_ERROR:
131            case Z_MEM_ERROR:
132                (void)inflateEnd(&strm);
133                return ret;
134            }
135            have = CHUNK - strm.avail_out;
136            if (fwrite(out, 1, have, dest) != have || ferror(dest)) {
137                (void)inflateEnd(&strm);
138                return Z_ERRNO;
139            }
140        } while (strm.avail_out == 0);
141
142        /* done when inflate() says it's done */
143    } while (ret != Z_STREAM_END);
144
145    /* clean up and return */
146    (void)inflateEnd(&strm);
147    return ret == Z_STREAM_END ? Z_OK : Z_DATA_ERROR;
148}
149
150/* report a zlib or i/o error */
151void zerr(int ret)
152{
153    fputs("zpipe: ", stderr);
154    switch (ret) {
155    case Z_ERRNO:
156        if (ferror(stdin))
157            fputs("error reading stdin\n", stderr);
158        if (ferror(stdout))
159            fputs("error writing stdout\n", stderr);
160        break;
161    case Z_STREAM_ERROR:
162        fputs("invalid compression level\n", stderr);
163        break;
164    case Z_DATA_ERROR:
165        fputs("invalid or incomplete deflate data\n", stderr);
166        break;
167    case Z_MEM_ERROR:
168        fputs("out of memory\n", stderr);
169        break;
170    case Z_VERSION_ERROR:
171        fputs("zlib version mismatch!\n", stderr);
172    }
173}
174
175/* compress or decompress from stdin to stdout */
176int main(int argc, char **argv)
177{
178    int ret;
179
180    /* avoid end-of-line conversions */
181    SET_BINARY_MODE(stdin);
182    SET_BINARY_MODE(stdout);
183
184    /* do compression if no arguments */
185    if (argc == 1) {
186        ret = def(stdin, stdout, Z_DEFAULT_COMPRESSION);
187        if (ret != Z_OK)
188            zerr(ret);
189        return ret;
190    }
191
192    /* do decompression if -d specified */
193    else if (argc == 2 && strcmp(argv[1], "-d") == 0) {
194        ret = inf(stdin, stdout);
195        if (ret != Z_OK)
196            zerr(ret);
197        return ret;
198    }
199
200    /* otherwise, report usage */
201    else {
202        fputs("zpipe usage: zpipe [-d] < source > dest\n", stderr);
203        return 1;
204    }
205}
206