source: rtems/cpukit/zlib/examples/zpipe.c @ 8198f69

4.115
Last change on this file since 8198f69 was 8198f69, checked in by Ralf Corsepius <ralf.corsepius@…>, on 03/18/11 at 10:10:55

Import zlib-1.2.3

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File size: 5.7 KB
RevLine 
[959f7df2]1/* zpipe.c: example of proper use of zlib's inflate() and deflate()
2   Not copyrighted -- provided to the public domain
3   Version 1.2  9 November 2004  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
[8198f69]10   1.3   6 Apr 2005  Remove incorrect assertion in inf()
[959f7df2]11 */
12
13#include <stdio.h>
14#include <string.h>
15#include <assert.h>
16#include "zlib.h"
17
18#define CHUNK 16384
19
20/* Compress from file source to file dest until EOF on source.
21   def() returns Z_OK on success, Z_MEM_ERROR if memory could not be
22   allocated for processing, Z_STREAM_ERROR if an invalid compression
23   level is supplied, Z_VERSION_ERROR if the version of zlib.h and the
24   version of the library linked do not match, or Z_ERRNO if there is
25   an error reading or writing the files. */
26int def(FILE *source, FILE *dest, int level)
27{
28    int ret, flush;
29    unsigned have;
30    z_stream strm;
31    char in[CHUNK];
32    char out[CHUNK];
33
34    /* allocate deflate state */
35    strm.zalloc = Z_NULL;
36    strm.zfree = Z_NULL;
37    strm.opaque = Z_NULL;
38    ret = deflateInit(&strm, level);
39    if (ret != Z_OK)
40        return ret;
41
42    /* compress until end of file */
43    do {
44        strm.avail_in = fread(in, 1, CHUNK, source);
45        if (ferror(source)) {
46            (void)deflateEnd(&strm);
47            return Z_ERRNO;
48        }
49        flush = feof(source) ? Z_FINISH : Z_NO_FLUSH;
50        strm.next_in = in;
51
52        /* run deflate() on input until output buffer not full, finish
53           compression if all of source has been read in */
54        do {
55            strm.avail_out = CHUNK;
56            strm.next_out = out;
57            ret = deflate(&strm, flush);    /* no bad return value */
58            assert(ret != Z_STREAM_ERROR);  /* state not clobbered */
59            have = CHUNK - strm.avail_out;
60            if (fwrite(out, 1, have, dest) != have || ferror(dest)) {
61                (void)deflateEnd(&strm);
62                return Z_ERRNO;
63            }
64        } while (strm.avail_out == 0);
65        assert(strm.avail_in == 0);     /* all input will be used */
66
67        /* done when last data in file processed */
68    } while (flush != Z_FINISH);
69    assert(ret == Z_STREAM_END);        /* stream will be complete */
70
71    /* clean up and return */
72    (void)deflateEnd(&strm);
73    return Z_OK;
74}
75
76/* Decompress from file source to file dest until stream ends or EOF.
77   inf() returns Z_OK on success, Z_MEM_ERROR if memory could not be
78   allocated for processing, Z_DATA_ERROR if the deflate data is
79   invalid or incomplete, Z_VERSION_ERROR if the version of zlib.h and
80   the version of the library linked do not match, or Z_ERRNO if there
81   is an error reading or writing the files. */
82int inf(FILE *source, FILE *dest)
83{
84    int ret;
85    unsigned have;
86    z_stream strm;
87    char in[CHUNK];
88    char out[CHUNK];
89
90    /* allocate inflate state */
91    strm.zalloc = Z_NULL;
92    strm.zfree = Z_NULL;
93    strm.opaque = Z_NULL;
94    strm.avail_in = 0;
95    strm.next_in = Z_NULL;
96    ret = inflateInit(&strm);
97    if (ret != Z_OK)
98        return ret;
99
100    /* decompress until deflate stream ends or end of file */
101    do {
102        strm.avail_in = fread(in, 1, CHUNK, source);
103        if (ferror(source)) {
104            (void)inflateEnd(&strm);
105            return Z_ERRNO;
106        }
107        if (strm.avail_in == 0)
108            break;
109        strm.next_in = in;
110
111        /* run inflate() on input until output buffer not full */
112        do {
113            strm.avail_out = CHUNK;
114            strm.next_out = out;
115            ret = inflate(&strm, Z_NO_FLUSH);
116            assert(ret != Z_STREAM_ERROR);  /* state not clobbered */
117            switch (ret) {
118            case Z_NEED_DICT:
119                ret = Z_DATA_ERROR;     /* and fall through */
120            case Z_DATA_ERROR:
121            case Z_MEM_ERROR:
122                (void)inflateEnd(&strm);
123                return ret;
124            }
125            have = CHUNK - strm.avail_out;
126            if (fwrite(out, 1, have, dest) != have || ferror(dest)) {
127                (void)inflateEnd(&strm);
128                return Z_ERRNO;
129            }
130        } while (strm.avail_out == 0);
131
132        /* done when inflate() says it's done */
133    } while (ret != Z_STREAM_END);
134
135    /* clean up and return */
136    (void)inflateEnd(&strm);
137    return ret == Z_STREAM_END ? Z_OK : Z_DATA_ERROR;
138}
139
140/* report a zlib or i/o error */
141void zerr(int ret)
142{
143    fputs("zpipe: ", stderr);
144    switch (ret) {
145    case Z_ERRNO:
146        if (ferror(stdin))
147            fputs("error reading stdin\n", stderr);
148        if (ferror(stdout))
149            fputs("error writing stdout\n", stderr);
150        break;
151    case Z_STREAM_ERROR:
152        fputs("invalid compression level\n", stderr);
153        break;
154    case Z_DATA_ERROR:
155        fputs("invalid or incomplete deflate data\n", stderr);
156        break;
157    case Z_MEM_ERROR:
158        fputs("out of memory\n", stderr);
159        break;
160    case Z_VERSION_ERROR:
161        fputs("zlib version mismatch!\n", stderr);
162    }
163}
164
165/* compress or decompress from stdin to stdout */
166int main(int argc, char **argv)
167{
168    int ret;
169
170    /* do compression if no arguments */
171    if (argc == 1) {
172        ret = def(stdin, stdout, Z_DEFAULT_COMPRESSION);
173        if (ret != Z_OK)
174            zerr(ret);
175        return ret;
176    }
177
178    /* do decompression if -d specified */
179    else if (argc == 2 && strcmp(argv[1], "-d") == 0) {
180        ret = inf(stdin, stdout);
181        if (ret != Z_OK)
182            zerr(ret);
183        return ret;
184    }
185
186    /* otherwise, report usage */
187    else {
188        fputs("zpipe usage: zpipe [-d] < source > dest\n", stderr);
189        return 1;
190    }
191}
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