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authorArne Schwabe <arne@rfc2549.org>2012-04-16 19:21:14 +0200
committerArne Schwabe <arne@rfc2549.org>2012-04-16 19:21:14 +0200
commit3e4d8f433239c40311037616b1b8833a06651ae0 (patch)
tree98ab7fce0d011d34677b0beb762d389cb5c39199 /lzo/examples/precomp.c
Initial import
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+/* 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
+*/
+