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. */
 36 int 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. */
 92 int 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;//CHUNK=128K
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 */
151 void 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 */
176 int 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 }