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206 lines
6.2 KiB
C
206 lines
6.2 KiB
C
/* zpipe.c: example of proper use of zlib's inflate() and deflate()
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Not copyrighted -- provided to the public domain
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Version 1.4 11 December 2005 Mark Adler */
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/* Version history:
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1.0 30 Oct 2004 First version
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1.1 8 Nov 2004 Add void casting for unused return values
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Use switch statement for inflate() return values
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1.2 9 Nov 2004 Add assertions to document zlib guarantees
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1.3 6 Apr 2005 Remove incorrect assertion in inf()
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1.4 11 Dec 2005 Add hack to avoid MSDOS end-of-line conversions
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Avoid some compiler warnings for input and output buffers
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*/
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#include <stdio.h>
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#include <string.h>
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#include <assert.h>
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#include "zlib.h"
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#if defined(MSDOS) || defined(OS2) || defined(WIN32) || defined(__CYGWIN__)
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# include <fcntl.h>
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# include <io.h>
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# define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY)
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#else
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# define SET_BINARY_MODE(file)
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#endif
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#define CHUNK 16384
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/* Compress from file source to file dest until EOF on source.
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def() returns Z_OK on success, Z_MEM_ERROR if memory could not be
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allocated for processing, Z_STREAM_ERROR if an invalid compression
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level is supplied, Z_VERSION_ERROR if the version of zlib.h and the
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version of the library linked do not match, or Z_ERRNO if there is
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an error reading or writing the files. */
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int def(FILE *source, FILE *dest, int level)
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{
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int ret, flush;
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unsigned have;
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z_stream strm;
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unsigned char in[CHUNK];
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unsigned char out[CHUNK];
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/* allocate deflate state */
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strm.zalloc = Z_NULL;
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strm.zfree = Z_NULL;
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strm.opaque = Z_NULL;
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ret = deflateInit(&strm, level);
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if (ret != Z_OK)
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return ret;
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/* compress until end of file */
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do {
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strm.avail_in = fread(in, 1, CHUNK, source);
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if (ferror(source)) {
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(void)deflateEnd(&strm);
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return Z_ERRNO;
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}
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flush = feof(source) ? Z_FINISH : Z_NO_FLUSH;
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strm.next_in = in;
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/* run deflate() on input until output buffer not full, finish
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compression if all of source has been read in */
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do {
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strm.avail_out = CHUNK;
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strm.next_out = out;
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ret = deflate(&strm, flush); /* no bad return value */
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assert(ret != Z_STREAM_ERROR); /* state not clobbered */
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have = CHUNK - strm.avail_out;
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if (fwrite(out, 1, have, dest) != have || ferror(dest)) {
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(void)deflateEnd(&strm);
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return Z_ERRNO;
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}
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} while (strm.avail_out == 0);
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assert(strm.avail_in == 0); /* all input will be used */
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/* done when last data in file processed */
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} while (flush != Z_FINISH);
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assert(ret == Z_STREAM_END); /* stream will be complete */
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/* clean up and return */
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(void)deflateEnd(&strm);
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return Z_OK;
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}
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/* Decompress from file source to file dest until stream ends or EOF.
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inf() returns Z_OK on success, Z_MEM_ERROR if memory could not be
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allocated for processing, Z_DATA_ERROR if the deflate data is
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invalid or incomplete, Z_VERSION_ERROR if the version of zlib.h and
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the version of the library linked do not match, or Z_ERRNO if there
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is an error reading or writing the files. */
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int inf(FILE *source, FILE *dest)
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{
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int ret;
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unsigned have;
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z_stream strm;
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unsigned char in[CHUNK];
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unsigned char out[CHUNK];
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/* allocate inflate state */
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strm.zalloc = Z_NULL;
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strm.zfree = Z_NULL;
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strm.opaque = Z_NULL;
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strm.avail_in = 0;
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strm.next_in = Z_NULL;
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ret = inflateInit(&strm);
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if (ret != Z_OK)
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return ret;
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/* decompress until deflate stream ends or end of file */
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do {
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strm.avail_in = fread(in, 1, CHUNK, source);
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if (ferror(source)) {
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(void)inflateEnd(&strm);
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return Z_ERRNO;
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}
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if (strm.avail_in == 0)
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break;
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strm.next_in = in;
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/* run inflate() on input until output buffer not full */
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do {
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strm.avail_out = CHUNK;
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strm.next_out = out;
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ret = inflate(&strm, Z_NO_FLUSH);
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assert(ret != Z_STREAM_ERROR); /* state not clobbered */
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switch (ret) {
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case Z_NEED_DICT:
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ret = Z_DATA_ERROR; /* and fall through */
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case Z_DATA_ERROR:
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case Z_MEM_ERROR:
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(void)inflateEnd(&strm);
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return ret;
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}
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have = CHUNK - strm.avail_out;
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if (fwrite(out, 1, have, dest) != have || ferror(dest)) {
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(void)inflateEnd(&strm);
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return Z_ERRNO;
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}
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} while (strm.avail_out == 0);
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/* done when inflate() says it's done */
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} while (ret != Z_STREAM_END);
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/* clean up and return */
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(void)inflateEnd(&strm);
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return ret == Z_STREAM_END ? Z_OK : Z_DATA_ERROR;
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}
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/* report a zlib or i/o error */
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void zerr(int ret)
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{
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fputs("zpipe: ", stderr);
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switch (ret) {
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case Z_ERRNO:
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if (ferror(stdin))
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fputs("error reading stdin\n", stderr);
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if (ferror(stdout))
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fputs("error writing stdout\n", stderr);
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break;
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case Z_STREAM_ERROR:
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fputs("invalid compression level\n", stderr);
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break;
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case Z_DATA_ERROR:
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fputs("invalid or incomplete deflate data\n", stderr);
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break;
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case Z_MEM_ERROR:
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fputs("out of memory\n", stderr);
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break;
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case Z_VERSION_ERROR:
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fputs("zlib version mismatch!\n", stderr);
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}
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}
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/* compress or decompress from stdin to stdout */
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int main(int argc, char **argv)
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{
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int ret;
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/* avoid end-of-line conversions */
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SET_BINARY_MODE(stdin);
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SET_BINARY_MODE(stdout);
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/* do compression if no arguments */
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if (argc == 1) {
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ret = def(stdin, stdout, Z_DEFAULT_COMPRESSION);
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if (ret != Z_OK)
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zerr(ret);
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return ret;
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}
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/* do decompression if -d specified */
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else if (argc == 2 && strcmp(argv[1], "-d") == 0) {
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ret = inf(stdin, stdout);
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if (ret != Z_OK)
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zerr(ret);
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return ret;
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}
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/* otherwise, report usage */
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else {
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fputs("zpipe usage: zpipe [-d] < source > dest\n", stderr);
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return 1;
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}
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}
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