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Edit File: zpipe.c

/* zpipe.c: example of proper use of zlib's inflate() and deflate() Not copyrighted -- provided to the public domain Version 1.4 11 December 2005 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() 1.4 11 Dec 2005 Add hack to avoid MSDOS end-of-line conversions Avoid some compiler warnings for input and output buffers */ #include <stdio.h> #include <string.h> #include <assert.h> #include "zlib.h" #if defined(MSDOS) || defined(OS2) || defined(WIN32) || defined(__CYGWIN__) # include <fcntl.h> # include <io.h> # define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY) #else # define SET_BINARY_MODE(file) #endif #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; unsigned char in[CHUNK]; unsigned 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; unsigned char in[CHUNK]; unsigned 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; /* avoid end-of-line conversions */ SET_BINARY_MODE(stdin); SET_BINARY_MODE(stdout); /* 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; } }