1/* precomp.c -- example program: how to generate pre-compressed data
2
3   This file is part of the LZO real-time data compression library.
4
5   Copyright (C) 2008 Markus Franz Xaver Johannes Oberhumer
6   Copyright (C) 2007 Markus Franz Xaver Johannes Oberhumer
7   Copyright (C) 2006 Markus Franz Xaver Johannes Oberhumer
8   Copyright (C) 2005 Markus Franz Xaver Johannes Oberhumer
9   Copyright (C) 2004 Markus Franz Xaver Johannes Oberhumer
10   Copyright (C) 2003 Markus Franz Xaver Johannes Oberhumer
11   Copyright (C) 2002 Markus Franz Xaver Johannes Oberhumer
12   Copyright (C) 2001 Markus Franz Xaver Johannes Oberhumer
13   Copyright (C) 2000 Markus Franz Xaver Johannes Oberhumer
14   Copyright (C) 1999 Markus Franz Xaver Johannes Oberhumer
15   Copyright (C) 1998 Markus Franz Xaver Johannes Oberhumer
16   Copyright (C) 1997 Markus Franz Xaver Johannes Oberhumer
17   Copyright (C) 1996 Markus Franz Xaver Johannes Oberhumer
18   All Rights Reserved.
19
20   The LZO library is free software; you can redistribute it and/or
21   modify it under the terms of the GNU General Public License as
22   published by the Free Software Foundation; either version 2 of
23   the License, or (at your option) any later version.
24
25   The LZO library is distributed in the hope that it will be useful,
26   but WITHOUT ANY WARRANTY; without even the implied warranty of
27   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
28   GNU General Public License for more details.
29
30   You should have received a copy of the GNU General Public License
31   along with the LZO library; see the file COPYING.
32   If not, write to the Free Software Foundation, Inc.,
33   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
34
35   Markus F.X.J. Oberhumer
36   <markus@oberhumer.com>
37   http://www.oberhumer.com/opensource/lzo/
38 */
39
40
41/*************************************************************************
42// This program shows how to generate pre-compressed data.
43//
44// Please study LZO.FAQ and simple.c first.
45//
46// We will be trying both LZO1X-999 and LZO1Y-999 and choose
47// the algorithm that achieves the best compression ratio.
48**************************************************************************/
49
50#include "lzo/lzoconf.h"
51#include "lzo/lzo1x.h"
52#include "lzo/lzo1y.h"
53
54#define USE_LZO1X 1
55#define USE_LZO1Y 1
56
57#define PARANOID 1
58
59
60/* portability layer */
61#define WANT_LZO_MALLOC 1
62#define WANT_LZO_FREAD 1
63#define WANT_LZO_WILDARGV 1
64#include "examples/portab.h"
65
66
67/*************************************************************************
68//
69**************************************************************************/
70
71int __lzo_cdecl_main main(int argc, char *argv[])
72{
73    int r;
74
75    lzo_bytep in;
76    lzo_uint in_len;
77
78    lzo_bytep out;
79    lzo_uint out_bufsize;
80    lzo_uint out_len = 0;
81
82    lzo_bytep wrkmem;
83    lzo_uint wrk_len;
84
85    lzo_uint best_len;
86    int best_compress = -1;
87
88    lzo_uint orig_len;
89    lzo_uint32 uncompressed_checksum;
90    lzo_uint32 compressed_checksum;
91
92    FILE *f;
93    const char *progname = NULL;
94    const char *in_name = NULL;
95    const char *out_name = NULL;
96    long l;
97
98
99    lzo_wildargv(&argc, &argv);
100
101    printf("\nLZO real-time data compression library (v%s, %s).\n",
102           lzo_version_string(), lzo_version_date());
103    printf("Copyright (C) 1996-2008 Markus Franz Xaver Johannes Oberhumer\nAll Rights Reserved.\n\n");
104
105    progname = argv[0];
106    if (argc < 2 || argc > 3)
107    {
108        printf("usage: %s file [output-file]\n", progname);
109        exit(1);
110    }
111    in_name = argv[1];
112    if (argc > 2) out_name = argv[2];
113
114/*
115 * Step 1: initialize the LZO library
116 */
117    if (lzo_init() != LZO_E_OK)
118    {
119        printf("internal error - lzo_init() failed !!!\n");
120        printf("(this usually indicates a compiler bug - try recompiling\nwithout optimizations, and enable `-DLZO_DEBUG' for diagnostics)\n");
121        exit(1);
122    }
123
124/*
125 * Step 2: allocate the work-memory
126 */
127    wrk_len = 1;
128#ifdef USE_LZO1X
129    if (wrk_len < LZO1X_999_MEM_COMPRESS)
130        wrk_len = LZO1X_999_MEM_COMPRESS;
131#endif
132#ifdef USE_LZO1Y
133    if (wrk_len < LZO1Y_999_MEM_COMPRESS)
134        wrk_len = LZO1Y_999_MEM_COMPRESS;
135#endif
136    wrkmem = (lzo_bytep) lzo_malloc(wrk_len);
137    if (wrkmem == NULL)
138    {
139        printf("%s: out of memory\n", progname);
140        exit(1);
141    }
142
143/*
144 * Step 3: open the input file
145 */
146    f = fopen(in_name,"rb");
147    if (f == NULL)
148    {
149        printf("%s: cannot open file %s\n", progname, in_name);
150        exit(1);
151    }
152    fseek(f,0,SEEK_END);
153    l = ftell(f);
154    fseek(f,0,SEEK_SET);
155    if (l <= 0)
156    {
157        printf("%s: %s: empty file\n", progname, in_name);
158        fclose(f);
159        exit(1);
160    }
161    in_len = (lzo_uint) l;
162    out_bufsize = in_len + in_len / 16 + 64 + 3;
163    best_len = in_len;
164
165/*
166 * Step 4: allocate compression buffers and read the file
167 */
168    in = (lzo_bytep) lzo_malloc(in_len);
169    out = (lzo_bytep) lzo_malloc(out_bufsize);
170    if (in == NULL || out == NULL)
171    {
172        printf("%s: out of memory\n", progname);
173        exit(1);
174    }
175    in_len = (lzo_uint) lzo_fread(f,in,in_len);
176    printf("%s: loaded file %s: %ld bytes\n", progname, in_name, (long) in_len);
177    fclose(f);
178
179/*
180 * Step 5: compute a checksum of the uncompressed data
181 */
182    uncompressed_checksum = lzo_adler32(0,NULL,0);
183    uncompressed_checksum = lzo_adler32(uncompressed_checksum,in,in_len);
184
185/*
186 * Step 6a: compress from `in' to `out' with LZO1X-999
187 */
188#ifdef USE_LZO1X
189        out_len = out_bufsize;
190        r = lzo1x_999_compress(in,in_len,out,&out_len,wrkmem);
191        if (r != LZO_E_OK)
192        {
193            /* this should NEVER happen */
194            printf("internal error - compression failed: %d\n", r);
195            exit(1);
196        }
197        printf("LZO1X-999: %8lu -> %8lu\n", (unsigned long) in_len, (unsigned long) out_len);
198        if (out_len < best_len)
199        {
200            best_len = out_len;
201            best_compress = 1;      /* LZO1X-999 */
202        }
203#endif /* USE_LZO1X */
204
205/*
206 * Step 6b: compress from `in' to `out' with LZO1Y-999
207 */
208#ifdef USE_LZO1Y
209        out_len = out_bufsize;
210        r = lzo1y_999_compress(in,in_len,out,&out_len,wrkmem);
211        if (r != LZO_E_OK)
212        {
213            /* this should NEVER happen */
214            printf("internal error - compression failed: %d\n", r);
215            exit(1);
216        }
217        printf("LZO1Y-999: %8lu -> %8lu\n", (unsigned long) in_len, (unsigned long) out_len);
218        if (out_len < best_len)
219        {
220            best_len = out_len;
221            best_compress = 2;      /* LZO1Y-999 */
222        }
223#endif /* USE_LZO1Y */
224
225/*
226 * Step 7: check if compressible
227 */
228    if (best_len >= in_len)
229    {
230        printf("This file contains incompressible data.\n");
231        return 0;
232    }
233
234/*
235 * Step 8: compress data again using the best compressor found
236 */
237    out_len = out_bufsize;
238    if (best_compress == 1)
239        r = lzo1x_999_compress(in,in_len,out,&out_len,wrkmem);
240    else if (best_compress == 2)
241        r = lzo1y_999_compress(in,in_len,out,&out_len,wrkmem);
242    else
243        r = -100;
244    assert(r == LZO_E_OK);
245    assert(out_len == best_len);
246
247/*
248 * Step 9: optimize compressed data (compressed data is in `out' buffer)
249 */
250#if 1
251    /* Optimization does not require any data in the buffer that will
252     * hold the uncompressed data. To prove this, we clear the buffer.
253     */
254    lzo_memset(in,0,in_len);
255#endif
256
257    orig_len = in_len;
258    r = -100;
259#ifdef USE_LZO1X
260    if (best_compress == 1)
261        r = lzo1x_optimize(out,out_len,in,&orig_len,NULL);
262#endif
263#ifdef USE_LZO1Y
264    if (best_compress == 2)
265        r = lzo1y_optimize(out,out_len,in,&orig_len,NULL);
266#endif
267    if (r != LZO_E_OK || orig_len != in_len)
268    {
269        /* this should NEVER happen */
270        printf("internal error - optimization failed: %d\n", r);
271        exit(1);
272    }
273
274/*
275 * Step 10: compute a checksum of the compressed data
276 */
277    compressed_checksum = lzo_adler32(0,NULL,0);
278    compressed_checksum = lzo_adler32(compressed_checksum,out,out_len);
279
280/*
281 * Step 11: write compressed data to a file
282 */
283    printf("%s: %s: %ld -> %ld, checksum 0x%08lx 0x%08lx\n",
284            progname, in_name, (long) in_len, (long) out_len,
285            (long) uncompressed_checksum, (long) compressed_checksum);
286
287    if (out_name && out_name[0])
288    {
289        printf("%s: writing to file %s\n", progname, out_name);
290        f = fopen(out_name,"wb");
291        if (f == NULL)
292        {
293            printf("%s: cannot open output file %s\n", progname, out_name);
294            exit(1);
295        }
296        if (lzo_fwrite(f,out,out_len) != out_len || fclose(f) != 0)
297        {
298            printf("%s: write error !!\n", progname);
299            exit(1);
300        }
301    }
302
303/*
304 * Step 12: verify decompression
305 */
306#ifdef PARANOID
307    lzo_memset(in,0,in_len);    /* paranoia - clear output buffer */
308    orig_len = in_len;
309    r = -100;
310#ifdef USE_LZO1X
311    if (best_compress == 1)
312        r = lzo1x_decompress_safe(out,out_len,in,&orig_len,NULL);
313#endif
314#ifdef USE_LZO1Y
315    if (best_compress == 2)
316        r = lzo1y_decompress_safe(out,out_len,in,&orig_len,NULL);
317#endif
318    if (r != LZO_E_OK || orig_len != in_len)
319    {
320        /* this should NEVER happen */
321        printf("internal error - decompression failed: %d\n", r);
322        exit(1);
323    }
324    if (uncompressed_checksum != lzo_adler32(lzo_adler32(0,NULL,0),in,in_len))
325    {
326        /* this should NEVER happen */
327        printf("internal error - decompression data error\n");
328        exit(1);
329    }
330    /* Now you could also verify decompression under similar conditions as in
331     * your application, e.g. overlapping assembler decompression etc.
332     */
333#endif
334
335    lzo_free(in);
336    lzo_free(out);
337    lzo_free(wrkmem);
338
339    return 0;
340}
341
342/*
343vi:ts=4:et
344*/
345
346