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Diffstat (limited to 'examples/precomp.c')
| -rw-r--r-- | examples/precomp.c | 345 |
1 files changed, 345 insertions, 0 deletions
diff --git a/examples/precomp.c b/examples/precomp.c new file mode 100644 index 0000000..10f4e7f --- /dev/null +++ b/examples/precomp.c @@ -0,0 +1,345 @@ +/* precomp.c -- example program: how to generate pre-compressed data + + This file is part of the LZO real-time data compression library. + + Copyright (C) 2008 Markus Franz Xaver Johannes Oberhumer + Copyright (C) 2007 Markus Franz Xaver Johannes Oberhumer + Copyright (C) 2006 Markus Franz Xaver Johannes Oberhumer + Copyright (C) 2005 Markus Franz Xaver Johannes Oberhumer + Copyright (C) 2004 Markus Franz Xaver Johannes Oberhumer + Copyright (C) 2003 Markus Franz Xaver Johannes Oberhumer + Copyright (C) 2002 Markus Franz Xaver Johannes Oberhumer + Copyright (C) 2001 Markus Franz Xaver Johannes Oberhumer + Copyright (C) 2000 Markus Franz Xaver Johannes Oberhumer + Copyright (C) 1999 Markus Franz Xaver Johannes Oberhumer + Copyright (C) 1998 Markus Franz Xaver Johannes Oberhumer + Copyright (C) 1997 Markus Franz Xaver Johannes Oberhumer + Copyright (C) 1996 Markus Franz Xaver Johannes Oberhumer + All Rights Reserved. + + The LZO library is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License as + published by the Free Software Foundation; either version 2 of + the License, or (at your option) any later version. + + The LZO library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with the LZO library; see the file COPYING. + If not, write to the Free Software Foundation, Inc., + 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + + Markus F.X.J. Oberhumer + <markus@oberhumer.com> + http://www.oberhumer.com/opensource/lzo/ + */ + + +/************************************************************************* +// This program shows how to generate pre-compressed data. +// +// Please study LZO.FAQ and simple.c first. +// +// We will be trying both LZO1X-999 and LZO1Y-999 and choose +// the algorithm that achieves the best compression ratio. +**************************************************************************/ + +#include "lzo/lzoconf.h" +#include "lzo/lzo1x.h" +#include "lzo/lzo1y.h" + +#define USE_LZO1X 1 +#define USE_LZO1Y 1 + +#define PARANOID 1 + + +/* portability layer */ +#define WANT_LZO_MALLOC 1 +#define WANT_LZO_FREAD 1 +#define WANT_LZO_WILDARGV 1 +#include "examples/portab.h" + + +/************************************************************************* +// +**************************************************************************/ + +int __lzo_cdecl_main main(int argc, char *argv[]) +{ + int r; + + lzo_bytep in; + lzo_uint in_len; + + lzo_bytep out; + lzo_uint out_bufsize; + lzo_uint out_len = 0; + + lzo_bytep wrkmem; + lzo_uint wrk_len; + + lzo_uint best_len; + int best_compress = -1; + + lzo_uint orig_len; + lzo_uint32 uncompressed_checksum; + lzo_uint32 compressed_checksum; + + FILE *f; + const char *progname = NULL; + const char *in_name = NULL; + const char *out_name = NULL; + long l; + + + lzo_wildargv(&argc, &argv); + + printf("\nLZO real-time data compression library (v%s, %s).\n", + lzo_version_string(), lzo_version_date()); + printf("Copyright (C) 1996-2008 Markus Franz Xaver Johannes Oberhumer\nAll Rights Reserved.\n\n"); + + progname = argv[0]; + if (argc < 2 || argc > 3) + { + printf("usage: %s file [output-file]\n", progname); + exit(1); + } + in_name = argv[1]; + if (argc > 2) out_name = argv[2]; + +/* + * Step 1: initialize the LZO library + */ + if (lzo_init() != LZO_E_OK) + { + printf("internal error - lzo_init() failed !!!\n"); + printf("(this usually indicates a compiler bug - try recompiling\nwithout optimizations, and enable `-DLZO_DEBUG' for diagnostics)\n"); + exit(1); + } + +/* + * Step 2: allocate the work-memory + */ + wrk_len = 1; +#ifdef USE_LZO1X + if (wrk_len < LZO1X_999_MEM_COMPRESS) + wrk_len = LZO1X_999_MEM_COMPRESS; +#endif +#ifdef USE_LZO1Y + if (wrk_len < LZO1Y_999_MEM_COMPRESS) + wrk_len = LZO1Y_999_MEM_COMPRESS; +#endif + wrkmem = (lzo_bytep) lzo_malloc(wrk_len); + if (wrkmem == NULL) + { + printf("%s: out of memory\n", progname); + exit(1); + } + +/* + * Step 3: open the input file + */ + f = fopen(in_name,"rb"); + if (f == NULL) + { + printf("%s: cannot open file %s\n", progname, in_name); + exit(1); + } + fseek(f,0,SEEK_END); + l = ftell(f); + fseek(f,0,SEEK_SET); + if (l <= 0) + { + printf("%s: %s: empty file\n", progname, in_name); + fclose(f); + exit(1); + } + in_len = (lzo_uint) l; + out_bufsize = in_len + in_len / 16 + 64 + 3; + best_len = in_len; + +/* + * Step 4: allocate compression buffers and read the file + */ + in = (lzo_bytep) lzo_malloc(in_len); + out = (lzo_bytep) lzo_malloc(out_bufsize); + if (in == NULL || out == NULL) + { + printf("%s: out of memory\n", progname); + exit(1); + } + in_len = (lzo_uint) lzo_fread(f,in,in_len); + printf("%s: loaded file %s: %ld bytes\n", progname, in_name, (long) in_len); + fclose(f); + +/* + * Step 5: compute a checksum of the uncompressed data + */ + uncompressed_checksum = lzo_adler32(0,NULL,0); + uncompressed_checksum = lzo_adler32(uncompressed_checksum,in,in_len); + +/* + * Step 6a: compress from `in' to `out' with LZO1X-999 + */ +#ifdef USE_LZO1X + out_len = out_bufsize; + r = lzo1x_999_compress(in,in_len,out,&out_len,wrkmem); + if (r != LZO_E_OK) + { + /* this should NEVER happen */ + printf("internal error - compression failed: %d\n", r); + exit(1); + } + printf("LZO1X-999: %8lu -> %8lu\n", (unsigned long) in_len, (unsigned long) out_len); + if (out_len < best_len) + { + best_len = out_len; + best_compress = 1; /* LZO1X-999 */ + } +#endif /* USE_LZO1X */ + +/* + * Step 6b: compress from `in' to `out' with LZO1Y-999 + */ +#ifdef USE_LZO1Y + out_len = out_bufsize; + r = lzo1y_999_compress(in,in_len,out,&out_len,wrkmem); + if (r != LZO_E_OK) + { + /* this should NEVER happen */ + printf("internal error - compression failed: %d\n", r); + exit(1); + } + printf("LZO1Y-999: %8lu -> %8lu\n", (unsigned long) in_len, (unsigned long) out_len); + if (out_len < best_len) + { + best_len = out_len; + best_compress = 2; /* LZO1Y-999 */ + } +#endif /* USE_LZO1Y */ + +/* + * Step 7: check if compressible + */ + if (best_len >= in_len) + { + printf("This file contains incompressible data.\n"); + return 0; + } + +/* + * Step 8: compress data again using the best compressor found + */ + out_len = out_bufsize; + if (best_compress == 1) + r = lzo1x_999_compress(in,in_len,out,&out_len,wrkmem); + else if (best_compress == 2) + r = lzo1y_999_compress(in,in_len,out,&out_len,wrkmem); + else + r = -100; + assert(r == LZO_E_OK); + assert(out_len == best_len); + +/* + * Step 9: optimize compressed data (compressed data is in `out' buffer) + */ +#if 1 + /* Optimization does not require any data in the buffer that will + * hold the uncompressed data. To prove this, we clear the buffer. + */ + lzo_memset(in,0,in_len); +#endif + + orig_len = in_len; + r = -100; +#ifdef USE_LZO1X + if (best_compress == 1) + r = lzo1x_optimize(out,out_len,in,&orig_len,NULL); +#endif +#ifdef USE_LZO1Y + if (best_compress == 2) + r = lzo1y_optimize(out,out_len,in,&orig_len,NULL); +#endif + if (r != LZO_E_OK || orig_len != in_len) + { + /* this should NEVER happen */ + printf("internal error - optimization failed: %d\n", r); + exit(1); + } + +/* + * Step 10: compute a checksum of the compressed data + */ + compressed_checksum = lzo_adler32(0,NULL,0); + compressed_checksum = lzo_adler32(compressed_checksum,out,out_len); + +/* + * Step 11: write compressed data to a file + */ + printf("%s: %s: %ld -> %ld, checksum 0x%08lx 0x%08lx\n", + progname, in_name, (long) in_len, (long) out_len, + (long) uncompressed_checksum, (long) compressed_checksum); + + if (out_name && out_name[0]) + { + printf("%s: writing to file %s\n", progname, out_name); + f = fopen(out_name,"wb"); + if (f == NULL) + { + printf("%s: cannot open output file %s\n", progname, out_name); + exit(1); + } + if (lzo_fwrite(f,out,out_len) != out_len || fclose(f) != 0) + { + printf("%s: write error !!\n", progname); + exit(1); + } + } + +/* + * Step 12: verify decompression + */ +#ifdef PARANOID + lzo_memset(in,0,in_len); /* paranoia - clear output buffer */ + orig_len = in_len; + r = -100; +#ifdef USE_LZO1X + if (best_compress == 1) + r = lzo1x_decompress_safe(out,out_len,in,&orig_len,NULL); +#endif +#ifdef USE_LZO1Y + if (best_compress == 2) + r = lzo1y_decompress_safe(out,out_len,in,&orig_len,NULL); +#endif + if (r != LZO_E_OK || orig_len != in_len) + { + /* this should NEVER happen */ + printf("internal error - decompression failed: %d\n", r); + exit(1); + } + if (uncompressed_checksum != lzo_adler32(lzo_adler32(0,NULL,0),in,in_len)) + { + /* this should NEVER happen */ + printf("internal error - decompression data error\n"); + exit(1); + } + /* Now you could also verify decompression under similar conditions as in + * your application, e.g. overlapping assembler decompression etc. + */ +#endif + + lzo_free(in); + lzo_free(out); + lzo_free(wrkmem); + + return 0; +} + +/* +vi:ts=4:et +*/ + |