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Diffstat (limited to 'zlib/examples/zpipe.c')
| -rw-r--r-- | zlib/examples/zpipe.c | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/zlib/examples/zpipe.c b/zlib/examples/zpipe.c new file mode 100644 index 000000000..26abb56a9 --- /dev/null +++ b/zlib/examples/zpipe.c @@ -0,0 +1,191 @@ +/* zpipe.c: example of proper use of zlib's inflate() and deflate() + Not copyrighted -- provided to the public domain + Version 1.2 9 November 2004 Mark Adler */ + +/* Version history: + 1.0 30 Oct 2004 First version + 1.1 8 Nov 2004 Add void casting for unused return values + Use switch statement for inflate() return values + 1.2 9 Nov 2004 Add assertions to document zlib guarantees + 1.3 6 Apr 2005 Remove incorrect assertion in inf() + */ + +#include <stdio.h> +#include <string.h> +#include <assert.h> +#include "zlib.h" + +#define CHUNK 16384 + +/* Compress from file source to file dest until EOF on source. + def() returns Z_OK on success, Z_MEM_ERROR if memory could not be + allocated for processing, Z_STREAM_ERROR if an invalid compression + level is supplied, Z_VERSION_ERROR if the version of zlib.h and the + version of the library linked do not match, or Z_ERRNO if there is + an error reading or writing the files. */ +int def(FILE *source, FILE *dest, int level) +{ + int ret, flush; + unsigned have; + z_stream strm; + char in[CHUNK]; + char out[CHUNK]; + + /* allocate deflate state */ + strm.zalloc = Z_NULL; + strm.zfree = Z_NULL; + strm.opaque = Z_NULL; + ret = deflateInit(&strm, level); + if (ret != Z_OK) + return ret; + + /* compress until end of file */ + do { + strm.avail_in = fread(in, 1, CHUNK, source); + if (ferror(source)) { + (void)deflateEnd(&strm); + return Z_ERRNO; + } + flush = feof(source) ? Z_FINISH : Z_NO_FLUSH; + strm.next_in = in; + + /* run deflate() on input until output buffer not full, finish + compression if all of source has been read in */ + do { + strm.avail_out = CHUNK; + strm.next_out = out; + ret = deflate(&strm, flush); /* no bad return value */ + assert(ret != Z_STREAM_ERROR); /* state not clobbered */ + have = CHUNK - strm.avail_out; + if (fwrite(out, 1, have, dest) != have || ferror(dest)) { + (void)deflateEnd(&strm); + return Z_ERRNO; + } + } while (strm.avail_out == 0); + assert(strm.avail_in == 0); /* all input will be used */ + + /* done when last data in file processed */ + } while (flush != Z_FINISH); + assert(ret == Z_STREAM_END); /* stream will be complete */ + + /* clean up and return */ + (void)deflateEnd(&strm); + return Z_OK; +} + +/* Decompress from file source to file dest until stream ends or EOF. + inf() returns Z_OK on success, Z_MEM_ERROR if memory could not be + allocated for processing, Z_DATA_ERROR if the deflate data is + invalid or incomplete, Z_VERSION_ERROR if the version of zlib.h and + the version of the library linked do not match, or Z_ERRNO if there + is an error reading or writing the files. */ +int inf(FILE *source, FILE *dest) +{ + int ret; + unsigned have; + z_stream strm; + char in[CHUNK]; + char out[CHUNK]; + + /* allocate inflate state */ + strm.zalloc = Z_NULL; + strm.zfree = Z_NULL; + strm.opaque = Z_NULL; + strm.avail_in = 0; + strm.next_in = Z_NULL; + ret = inflateInit(&strm); + if (ret != Z_OK) + return ret; + + /* decompress until deflate stream ends or end of file */ + do { + strm.avail_in = fread(in, 1, CHUNK, source); + if (ferror(source)) { + (void)inflateEnd(&strm); + return Z_ERRNO; + } + if (strm.avail_in == 0) + break; + strm.next_in = in; + + /* run inflate() on input until output buffer not full */ + do { + strm.avail_out = CHUNK; + strm.next_out = out; + ret = inflate(&strm, Z_NO_FLUSH); + assert(ret != Z_STREAM_ERROR); /* state not clobbered */ + switch (ret) { + case Z_NEED_DICT: + ret = Z_DATA_ERROR; /* and fall through */ + case Z_DATA_ERROR: + case Z_MEM_ERROR: + (void)inflateEnd(&strm); + return ret; + } + have = CHUNK - strm.avail_out; + if (fwrite(out, 1, have, dest) != have || ferror(dest)) { + (void)inflateEnd(&strm); + return Z_ERRNO; + } + } while (strm.avail_out == 0); + + /* done when inflate() says it's done */ + } while (ret != Z_STREAM_END); + + /* clean up and return */ + (void)inflateEnd(&strm); + return ret == Z_STREAM_END ? Z_OK : Z_DATA_ERROR; +} + +/* report a zlib or i/o error */ +void zerr(int ret) +{ + fputs("zpipe: ", stderr); + switch (ret) { + case Z_ERRNO: + if (ferror(stdin)) + fputs("error reading stdin\n", stderr); + if (ferror(stdout)) + fputs("error writing stdout\n", stderr); + break; + case Z_STREAM_ERROR: + fputs("invalid compression level\n", stderr); + break; + case Z_DATA_ERROR: + fputs("invalid or incomplete deflate data\n", stderr); + break; + case Z_MEM_ERROR: + fputs("out of memory\n", stderr); + break; + case Z_VERSION_ERROR: + fputs("zlib version mismatch!\n", stderr); + } +} + +/* compress or decompress from stdin to stdout */ +int main(int argc, char **argv) +{ + int ret; + + /* do compression if no arguments */ + if (argc == 1) { + ret = def(stdin, stdout, Z_DEFAULT_COMPRESSION); + if (ret != Z_OK) + zerr(ret); + return ret; + } + + /* do decompression if -d specified */ + else if (argc == 2 && strcmp(argv[1], "-d") == 0) { + ret = inf(stdin, stdout); + if (ret != Z_OK) + zerr(ret); + return ret; + } + + /* otherwise, report usage */ + else { + fputs("zpipe usage: zpipe [-d] < source > dest\n", stderr); + return 1; + } +} |