/* example.c -- usage example of the zlib compression library * Copyright (C) 1995-2004 Jean-loup Gailly. * For conditions of distribution and use, see copyright notice in zlib.h */ /* @(#) $Id: example.c,v 1.1.1.2 2002/03/11 21:53:23 tromey Exp $ */ #include #include "zlib.h" #ifdef STDC # include # include #endif #if defined(VMS) || defined(RISCOS) # define TESTFILE "foo-gz" #else # define TESTFILE "foo.gz" #endif #define CHECK_ERR(err, msg) { \ if (err != Z_OK) { \ fprintf(stderr, "%s error: %d\n", msg, err); \ exit(1); \ } \ } const char hello[] = "hello, hello!"; /* "hello world" would be more standard, but the repeated "hello" * stresses the compression code better, sorry... */ const char dictionary[] = "hello"; uLong dictId; /* Adler32 value of the dictionary */ void test_compress OF((Byte *compr, uLong comprLen, Byte *uncompr, uLong uncomprLen)); void test_gzio OF((const char *fname, Byte *uncompr, uLong uncomprLen)); void test_deflate OF((Byte *compr, uLong comprLen)); void test_inflate OF((Byte *compr, uLong comprLen, Byte *uncompr, uLong uncomprLen)); void test_large_deflate OF((Byte *compr, uLong comprLen, Byte *uncompr, uLong uncomprLen)); void test_large_inflate OF((Byte *compr, uLong comprLen, Byte *uncompr, uLong uncomprLen)); void test_flush OF((Byte *compr, uLong *comprLen)); void test_sync OF((Byte *compr, uLong comprLen, Byte *uncompr, uLong uncomprLen)); void test_dict_deflate OF((Byte *compr, uLong comprLen)); void test_dict_inflate OF((Byte *compr, uLong comprLen, Byte *uncompr, uLong uncomprLen)); int main OF((int argc, char *argv[])); /* =========================================================================== * Test compress() and uncompress() */ void test_compress(compr, comprLen, uncompr, uncomprLen) Byte *compr, *uncompr; uLong comprLen, uncomprLen; { int err; uLong len = (uLong)strlen(hello)+1; err = compress(compr, &comprLen, (const Bytef*)hello, len); CHECK_ERR(err, "compress"); strcpy((char*)uncompr, "garbage"); err = uncompress(uncompr, &uncomprLen, compr, comprLen); CHECK_ERR(err, "uncompress"); if (strcmp((char*)uncompr, hello)) { fprintf(stderr, "bad uncompress\n"); exit(1); } else { printf("uncompress(): %s\n", (char *)uncompr); } } /* =========================================================================== * Test read/write of .gz files */ void test_gzio(fname, uncompr, uncomprLen) const char *fname; /* compressed file name */ Byte *uncompr; uLong uncomprLen; { #ifdef NO_GZCOMPRESS fprintf(stderr, "NO_GZCOMPRESS -- gz* functions cannot compress\n"); #else int err; int len = (int)strlen(hello)+1; gzFile file; z_off_t pos; file = gzopen(fname, "wb"); if (file == NULL) { fprintf(stderr, "gzopen error\n"); exit(1); } gzputc(file, 'h'); if (gzputs(file, "ello") != 4) { fprintf(stderr, "gzputs err: %s\n", gzerror(file, &err)); exit(1); } if (gzprintf(file, ", %s!", "hello") != 8) { fprintf(stderr, "gzprintf err: %s\n", gzerror(file, &err)); exit(1); } gzseek(file, 1L, SEEK_CUR); /* add one zero byte */ gzclose(file); file = gzopen(fname, "rb"); if (file == NULL) { fprintf(stderr, "gzopen error\n"); exit(1); } strcpy((char*)uncompr, "garbage"); if (gzread(file, uncompr, (unsigned)uncomprLen) != len) { fprintf(stderr, "gzread err: %s\n", gzerror(file, &err)); exit(1); } if (strcmp((char*)uncompr, hello)) { fprintf(stderr, "bad gzread: %s\n", (char*)uncompr); exit(1); } else { printf("gzread(): %s\n", (char*)uncompr); } pos = gzseek(file, -8L, SEEK_CUR); if (pos != 6 || gztell(file) != pos) { fprintf(stderr, "gzseek error, pos=%ld, gztell=%ld\n", (long)pos, (long)gztell(file)); exit(1); } if (gzgetc(file) != ' ') { fprintf(stderr, "gzgetc error\n"); exit(1); } if (gzungetc(' ', file) != ' ') { fprintf(stderr, "gzungetc error\n"); exit(1); } gzgets(file, (char*)uncompr, (int)uncomprLen); if (strlen((char*)uncompr) != 7) { /* " hello!" */ fprintf(stderr, "gzgets err after gzseek: %s\n", gzerror(file, &err)); exit(1); } if (strcmp((char*)uncompr, hello + 6)) { fprintf(stderr, "bad gzgets after gzseek\n"); exit(1); } else { printf("gzgets() after gzseek: %s\n", (char*)uncompr); } gzclose(file); #endif } /* =========================================================================== * Test deflate() with small buffers */ void test_deflate(compr, comprLen) Byte *compr; uLong comprLen; { z_stream c_stream; /* compression stream */ int err; uLong len = (uLong)strlen(hello)+1; c_stream.zalloc = (alloc_func)0; c_stream.zfree = (free_func)0; c_stream.opaque = (voidpf)0; err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION); CHECK_ERR(err, "deflateInit"); c_stream.next_in = (Bytef*)hello; c_stream.next_out = compr; while (c_stream.total_in != len && c_stream.total_out < comprLen) { c_stream.avail_in = c_stream.avail_out = 1; /* force small buffers */ err = deflate(&c_stream, Z_NO_FLUSH); CHECK_ERR(err, "deflate"); } /* Finish the stream, still forcing small buffers: */ for (;;) { c_stream.avail_out = 1; err = deflate(&c_stream, Z_FINISH); if (err == Z_STREAM_END) break; CHECK_ERR(err, "deflate"); } err = deflateEnd(&c_stream); CHECK_ERR(err, "deflateEnd"); } /* =========================================================================== * Test inflate() with small buffers */ void test_inflate(compr, comprLen, uncompr, uncomprLen) Byte *compr, *uncompr; uLong comprLen, uncomprLen; { int err; z_stream d_stream; /* decompression stream */ strcpy((char*)uncompr, "garbage"); d_stream.zalloc = (alloc_func)0; d_stream.zfree = (free_func)0; d_stream.opaque = (voidpf)0; d_stream.next_in = compr; d_stream.avail_in = 0; d_stream.next_out = uncompr; err = inflateInit(&d_stream); CHECK_ERR(err, "inflateInit"); while (d_stream.total_out < uncomprLen && d_stream.total_in < comprLen) { d_stream.avail_in = d_stream.avail_out = 1; /* force small buffers */ err = inflate(&d_stream, Z_NO_FLUSH); if (err == Z_STREAM_END) break; CHECK_ERR(err, "inflate"); } err = inflateEnd(&d_stream); CHECK_ERR(err, "inflateEnd"); if (strcmp((char*)uncompr, hello)) { fprintf(stderr, "bad inflate\n"); exit(1); } else { printf("inflate(): %s\n", (char *)uncompr); } } /* =========================================================================== * Test deflate() with large buffers and dynamic change of compression level */ void test_large_deflate(compr, comprLen, uncompr, uncomprLen) Byte *compr, *uncompr; uLong comprLen, uncomprLen; { z_stream c_stream; /* compression stream */ int err; c_stream.zalloc = (alloc_func)0; c_stream.zfree = (free_func)0; c_stream.opaque = (voidpf)0; err = deflateInit(&c_stream, Z_BEST_SPEED); CHECK_ERR(err, "deflateInit"); c_stream.next_out = compr; c_stream.avail_out = (uInt)comprLen; /* At this point, uncompr is still mostly zeroes, so it should compress * very well: */ c_stream.next_in = uncompr; c_stream.avail_in = (uInt)uncomprLen; err = deflate(&c_stream, Z_NO_FLUSH); CHECK_ERR(err, "deflate"); if (c_stream.avail_in != 0) { fprintf(stderr, "deflate not greedy\n"); exit(1); } /* Feed in already compressed data and switch to no compression: */ deflateParams(&c_stream, Z_NO_COMPRESSION, Z_DEFAULT_STRATEGY); c_stream.next_in = compr; c_stream.avail_in = (uInt)comprLen/2; err = deflate(&c_stream, Z_NO_FLUSH); CHECK_ERR(err, "deflate"); /* Switch back to compressing mode: */ deflateParams(&c_stream, Z_BEST_COMPRESSION, Z_FILTERED); c_stream.next_in = uncompr; c_stream.avail_in = (uInt)uncomprLen; err = deflate(&c_stream, Z_NO_FLUSH); CHECK_ERR(err, "deflate"); err = deflate(&c_stream, Z_FINISH); if (err != Z_STREAM_END) { fprintf(stderr, "deflate should report Z_STREAM_END\n"); exit(1); } err = deflateEnd(&c_stream); CHECK_ERR(err, "deflateEnd"); } /* =========================================================================== * Test inflate() with large buffers */ void test_large_inflate(compr, comprLen, uncompr, uncomprLen) Byte *compr, *uncompr; uLong comprLen, uncomprLen; { int err; z_stream d_stream; /* decompression stream */ strcpy((char*)uncompr, "garbage"); d_stream.zalloc = (alloc_func)0; d_stream.zfree = (free_func)0; d_stream.opaque = (voidpf)0; d_stream.next_in = compr; d_stream.avail_in = (uInt)comprLen; err = inflateInit(&d_stream); CHECK_ERR(err, "inflateInit"); for (;;) { d_stream.next_out = uncompr; /* discard the output */ d_stream.avail_out = (uInt)uncomprLen; err = inflate(&d_stream, Z_NO_FLUSH); if (err == Z_STREAM_END) break; CHECK_ERR(err, "large inflate"); } err = inflateEnd(&d_stream); CHECK_ERR(err, "inflateEnd"); if (d_stream.total_out != 2*uncomprLen + comprLen/2) { fprintf(stderr, "bad large inflate: %ld\n", d_stream.total_out); exit(1); } else { printf("large_inflate(): OK\n"); } } /* =========================================================================== * Test deflate() with full flush */ void test_flush(compr, comprLen) Byte *compr; uLong *comprLen; { z_stream c_stream; /* compression stream */ int err; uInt len = (uInt)strlen(hello)+1; c_stream.zalloc = (alloc_func)0; c_stream.zfree = (free_func)0; c_stream.opaque = (voidpf)0; err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION); CHECK_ERR(err, "deflateInit"); c_stream.next_in = (Bytef*)hello; c_stream.next_out = compr; c_stream.avail_in = 3; c_stream.avail_out = (uInt)*comprLen; err = deflate(&c_stream, Z_FULL_FLUSH); CHECK_ERR(err, "deflate"); compr[3]++; /* force an error in first compressed block */ c_stream.avail_in = len - 3; err = deflate(&c_stream, Z_FINISH); if (err != Z_STREAM_END) { CHECK_ERR(err, "deflate"); } err = deflateEnd(&c_stream); CHECK_ERR(err, "deflateEnd"); *comprLen = c_stream.total_out; } /* =========================================================================== * Test inflateSync() */ void test_sync(compr, comprLen, uncompr, uncomprLen) Byte *compr, *uncompr; uLong comprLen, uncomprLen; { int err; z_stream d_stream; /* decompression stream */ strcpy((char*)uncompr, "garbage"); d_stream.zalloc = (alloc_func)0; d_stream.zfree = (free_func)0; d_stream.opaque = (voidpf)0; d_stream.next_in = compr; d_stream.avail_in = 2; /* just read the zlib header */ err = inflateInit(&d_stream); CHECK_ERR(err, "inflateInit"); d_stream.next_out = uncompr; d_stream.avail_out = (uInt)uncomprLen; inflate(&d_stream, Z_NO_FLUSH); CHECK_ERR(err, "inflate"); d_stream.avail_in = (uInt)comprLen-2; /* read all compressed data */ err = inflateSync(&d_stream); /* but skip the damaged part */ CHECK_ERR(err, "inflateSync"); err = inflate(&d_stream, Z_FINISH); if (err != Z_DATA_ERROR) { fprintf(stderr, "inflate should report DATA_ERROR\n"); /* Because of incorrect adler32 */ exit(1); } err = inflateEnd(&d_stream); CHECK_ERR(err, "inflateEnd"); printf("after inflateSync(): hel%s\n", (char *)uncompr); } /* =========================================================================== * Test deflate() with preset dictionary */ void test_dict_deflate(compr, comprLen) Byte *compr; uLong comprLen; { z_stream c_stream; /* compression stream */ int err; c_stream.zalloc = (alloc_func)0; c_stream.zfree = (free_func)0; c_stream.opaque = (voidpf)0; err = deflateInit(&c_stream, Z_BEST_COMPRESSION); CHECK_ERR(err, "deflateInit"); err = deflateSetDictionary(&c_stream, (const Bytef*)dictionary, sizeof(dictionary)); CHECK_ERR(err, "deflateSetDictionary"); dictId = c_stream.adler; c_stream.next_out = compr; c_stream.avail_out = (uInt)comprLen; c_stream.next_in = (Bytef*)hello; c_stream.avail_in = (uInt)strlen(hello)+1; err = deflate(&c_stream, Z_FINISH); if (err != Z_STREAM_END) { fprintf(stderr, "deflate should report Z_STREAM_END\n"); exit(1); } err = deflateEnd(&c_stream); CHECK_ERR(err, "deflateEnd"); } /* =========================================================================== * Test inflate() with a preset dictionary */ void test_dict_inflate(compr, comprLen, uncompr, uncomprLen) Byte *compr, *uncompr; uLong comprLen, uncomprLen; { int err; z_stream d_stream; /* decompression stream */ strcpy((char*)uncompr, "garbage"); d_stream.zalloc = (alloc_func)0; d_stream.zfree = (free_func)0; d_stream.opaque = (voidpf)0; d_stream.next_in = compr; d_stream.avail_in = (uInt)comprLen; err = inflateInit(&d_stream); CHECK_ERR(err, "inflateInit"); d_stream.next_out = uncompr; d_stream.avail_out = (uInt)uncomprLen; for (;;) { err = inflate(&d_stream, Z_NO_FLUSH); if (err == Z_STREAM_END) break; if (err == Z_NEED_DICT) { if (d_stream.adler != dictId) { fprintf(stderr, "unexpected dictionary"); exit(1); } err = inflateSetDictionary(&d_stream, (const Bytef*)dictionary, sizeof(dictionary)); } CHECK_ERR(err, "inflate with dict"); } err = inflateEnd(&d_stream); CHECK_ERR(err, "inflateEnd"); if (strcmp((char*)uncompr, hello)) { fprintf(stderr, "bad inflate with dict\n"); exit(1); } else { printf("inflate with dictionary: %s\n", (char *)uncompr); } } /* =========================================================================== * Usage: example [output.gz [input.gz]] */ int main(argc, argv) int argc; char *argv[]; { Byte *compr, *uncompr; uLong comprLen = 10000*sizeof(int); /* don't overflow on MSDOS */ uLong uncomprLen = comprLen; static const char* myVersion = ZLIB_VERSION; if (zlibVersion()[0] != myVersion[0]) { fprintf(stderr, "incompatible zlib version\n"); exit(1); } else if (strcmp(zlibVersion(), ZLIB_VERSION) != 0) { fprintf(stderr, "warning: different zlib version\n"); } printf("zlib version %s = 0x%04x, compile flags = 0x%lx\n", ZLIB_VERSION, ZLIB_VERNUM, zlibCompileFlags()); compr = (Byte*)calloc((uInt)comprLen, 1); uncompr = (Byte*)calloc((uInt)uncomprLen, 1); /* compr and uncompr are cleared to avoid reading uninitialized * data and to ensure that uncompr compresses well. */ if (compr == Z_NULL || uncompr == Z_NULL) { printf("out of memory\n"); exit(1); } test_compress(compr, comprLen, uncompr, uncomprLen); test_gzio((argc > 1 ? argv[1] : TESTFILE), uncompr, uncomprLen); test_deflate(compr, comprLen); test_inflate(compr, comprLen, uncompr, uncomprLen); test_large_deflate(compr, comprLen, uncompr, uncomprLen); test_large_inflate(compr, comprLen, uncompr, uncomprLen); test_flush(compr, &comprLen); test_sync(compr, comprLen, uncompr, uncomprLen); comprLen = uncomprLen; test_dict_deflate(compr, comprLen); test_dict_inflate(compr, comprLen, uncompr, uncomprLen); free(compr); free(uncompr); return 0; }