1/*	$NetBSD: zpipe.c,v 1.1.1.1 2006/01/14 20:11:09 christos Exp $	*/
2
3/* zpipe.c: example of proper use of zlib's inflate() and deflate()
4   Not copyrighted -- provided to the public domain
5   Version 1.2  9 November 2004  Mark Adler */
6
7/* Version history:
8   1.0  30 Oct 2004  First version
9   1.1   8 Nov 2004  Add void casting for unused return values
10                     Use switch statement for inflate() return values
11   1.2   9 Nov 2004  Add assertions to document zlib guarantees
12   1.3   6 Apr 2005  Remove incorrect assertion in inf()
13 */
14
15#include <stdio.h>
16#include <string.h>
17#include <assert.h>
18#include "zlib.h"
19
20#define CHUNK 16384
21
22/* Compress from file source to file dest until EOF on source.
23   def() returns Z_OK on success, Z_MEM_ERROR if memory could not be
24   allocated for processing, Z_STREAM_ERROR if an invalid compression
25   level is supplied, Z_VERSION_ERROR if the version of zlib.h and the
26   version of the library linked do not match, or Z_ERRNO if there is
27   an error reading or writing the files. */
28int def(FILE *source, FILE *dest, int level)
29{
30    int ret, flush;
31    unsigned have;
32    z_stream strm;
33    char in[CHUNK];
34    char out[CHUNK];
35
36    /* allocate deflate state */
37    strm.zalloc = Z_NULL;
38    strm.zfree = Z_NULL;
39    strm.opaque = Z_NULL;
40    ret = deflateInit(&strm, level);
41    if (ret != Z_OK)
42        return ret;
43
44    /* compress until end of file */
45    do {
46        strm.avail_in = fread(in, 1, CHUNK, source);
47        if (ferror(source)) {
48            (void)deflateEnd(&strm);
49            return Z_ERRNO;
50        }
51        flush = feof(source) ? Z_FINISH : Z_NO_FLUSH;
52        strm.next_in = in;
53
54        /* run deflate() on input until output buffer not full, finish
55           compression if all of source has been read in */
56        do {
57            strm.avail_out = CHUNK;
58            strm.next_out = out;
59            ret = deflate(&strm, flush);    /* no bad return value */
60            assert(ret != Z_STREAM_ERROR);  /* state not clobbered */
61            have = CHUNK - strm.avail_out;
62            if (fwrite(out, 1, have, dest) != have || ferror(dest)) {
63                (void)deflateEnd(&strm);
64                return Z_ERRNO;
65            }
66        } while (strm.avail_out == 0);
67        assert(strm.avail_in == 0);     /* all input will be used */
68
69        /* done when last data in file processed */
70    } while (flush != Z_FINISH);
71    assert(ret == Z_STREAM_END);        /* stream will be complete */
72
73    /* clean up and return */
74    (void)deflateEnd(&strm);
75    return Z_OK;
76}
77
78/* Decompress from file source to file dest until stream ends or EOF.
79   inf() returns Z_OK on success, Z_MEM_ERROR if memory could not be
80   allocated for processing, Z_DATA_ERROR if the deflate data is
81   invalid or incomplete, Z_VERSION_ERROR if the version of zlib.h and
82   the version of the library linked do not match, or Z_ERRNO if there
83   is an error reading or writing the files. */
84int inf(FILE *source, FILE *dest)
85{
86    int ret;
87    unsigned have;
88    z_stream strm;
89    char in[CHUNK];
90    char out[CHUNK];
91
92    /* allocate inflate state */
93    strm.zalloc = Z_NULL;
94    strm.zfree = Z_NULL;
95    strm.opaque = Z_NULL;
96    strm.avail_in = 0;
97    strm.next_in = Z_NULL;
98    ret = inflateInit(&strm);
99    if (ret != Z_OK)
100        return ret;
101
102    /* decompress until deflate stream ends or end of file */
103    do {
104        strm.avail_in = fread(in, 1, CHUNK, source);
105        if (ferror(source)) {
106            (void)inflateEnd(&strm);
107            return Z_ERRNO;
108        }
109        if (strm.avail_in == 0)
110            break;
111        strm.next_in = in;
112
113        /* run inflate() on input until output buffer not full */
114        do {
115            strm.avail_out = CHUNK;
116            strm.next_out = out;
117            ret = inflate(&strm, Z_NO_FLUSH);
118            assert(ret != Z_STREAM_ERROR);  /* state not clobbered */
119            switch (ret) {
120            case Z_NEED_DICT:
121                ret = Z_DATA_ERROR;     /* and fall through */
122            case Z_DATA_ERROR:
123            case Z_MEM_ERROR:
124                (void)inflateEnd(&strm);
125                return ret;
126            }
127            have = CHUNK - strm.avail_out;
128            if (fwrite(out, 1, have, dest) != have || ferror(dest)) {
129                (void)inflateEnd(&strm);
130                return Z_ERRNO;
131            }
132        } while (strm.avail_out == 0);
133
134        /* done when inflate() says it's done */
135    } while (ret != Z_STREAM_END);
136
137    /* clean up and return */
138    (void)inflateEnd(&strm);
139    return ret == Z_STREAM_END ? Z_OK : Z_DATA_ERROR;
140}
141
142/* report a zlib or i/o error */
143void zerr(int ret)
144{
145    fputs("zpipe: ", stderr);
146    switch (ret) {
147    case Z_ERRNO:
148        if (ferror(stdin))
149            fputs("error reading stdin\n", stderr);
150        if (ferror(stdout))
151            fputs("error writing stdout\n", stderr);
152        break;
153    case Z_STREAM_ERROR:
154        fputs("invalid compression level\n", stderr);
155        break;
156    case Z_DATA_ERROR:
157        fputs("invalid or incomplete deflate data\n", stderr);
158        break;
159    case Z_MEM_ERROR:
160        fputs("out of memory\n", stderr);
161        break;
162    case Z_VERSION_ERROR:
163        fputs("zlib version mismatch!\n", stderr);
164    }
165}
166
167/* compress or decompress from stdin to stdout */
168int main(int argc, char **argv)
169{
170    int ret;
171
172    /* do compression if no arguments */
173    if (argc == 1) {
174        ret = def(stdin, stdout, Z_DEFAULT_COMPRESSION);
175        if (ret != Z_OK)
176            zerr(ret);
177        return ret;
178    }
179
180    /* do decompression if -d specified */
181    else if (argc == 2 && strcmp(argv[1], "-d") == 0) {
182        ret = inf(stdin, stdout);
183        if (ret != Z_OK)
184            zerr(ret);
185        return ret;
186    }
187
188    /* otherwise, report usage */
189    else {
190        fputs("zpipe usage: zpipe [-d] < source > dest\n", stderr);
191        return 1;
192    }
193}
194