1 /* simple.c -- the annotated simple example program for the LZO library
2
3 This file is part of the LZO real-time data compression library.
4
5 Copyright (C) 1996-2017 Markus Franz Xaver Johannes Oberhumer
6 All Rights Reserved.
7
8 The LZO library is free software; you can redistribute it and/or
9 modify it under the terms of the GNU General Public License as
10 published by the Free Software Foundation; either version 2 of
11 the License, or (at your option) any later version.
12
13 The LZO library is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with the LZO library; see the file COPYING.
20 If not, write to the Free Software Foundation, Inc.,
21 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
22
23 Markus F.X.J. Oberhumer
24 <markus@oberhumer.com>
25 http://www.oberhumer.com/opensource/lzo/
26 */
27
28
29 /*************************************************************************
30 // This program shows the basic usage of the LZO library.
31 // We will compress a block of data and decompress again.
32 //
33 // See also LZO.FAQ
34 **************************************************************************/
35
36 /* We will be using the LZO1X-1 algorithm, so we have
37 * to include <lzo/lzo1x.h>
38 */
39
40 #include <lzo/lzoconf.h>
41 #include <lzo/lzo1x.h>
42
43 /* portability layer */
44 static const char *progname = NULL;
45 #define WANT_LZO_MALLOC 1
46 #define WANT_XMALLOC 1
47 #include "examples/portab.h"
48
49
50 /* We want to compress the data block at 'in' with length 'IN_LEN' to
51 * the block at 'out'. Because the input block may be incompressible,
52 * we must provide a little more output space in case that compression
53 * is not possible.
54 */
55
56 #ifndef IN_LEN
57 #define IN_LEN (128*1024L)
58 #endif
59 #define OUT_LEN (IN_LEN + IN_LEN / 16 + 64 + 3)
60
61
62 /*************************************************************************
63 //
64 **************************************************************************/
65
main(int argc,char * argv[])66 int __lzo_cdecl_main main(int argc, char *argv[])
67 {
68 int r;
69 lzo_bytep in;
70 lzo_bytep out;
71 lzo_voidp wrkmem;
72 lzo_uint in_len;
73 lzo_uint out_len;
74 lzo_uint new_len;
75
76 if (argc < 0 && argv == NULL) /* avoid warning about unused args */
77 return 0;
78
79 printf("\nLZO real-time data compression library (v%s, %s).\n",
80 lzo_version_string(), lzo_version_date());
81 printf("Copyright (C) 1996-2017 Markus Franz Xaver Johannes Oberhumer\nAll Rights Reserved.\n\n");
82
83 /*
84 * Step 1: initialize the LZO library
85 */
86 if (lzo_init() != LZO_E_OK)
87 {
88 printf("internal error - lzo_init() failed !!!\n");
89 printf("(this usually indicates a compiler bug - try recompiling\nwithout optimizations, and enable '-DLZO_DEBUG' for diagnostics)\n");
90 return 4;
91 }
92
93 /*
94 * Step 2: allocate blocks and the work-memory
95 */
96 in = (lzo_bytep) xmalloc(IN_LEN);
97 out = (lzo_bytep) xmalloc(OUT_LEN);
98 wrkmem = (lzo_voidp) xmalloc(LZO1X_1_MEM_COMPRESS);
99 if (in == NULL || out == NULL || wrkmem == NULL)
100 {
101 printf("out of memory\n");
102 return 3;
103 }
104
105 /*
106 * Step 3: prepare the input block that will get compressed.
107 * We just fill it with zeros in this example program,
108 * but you would use your real-world data here.
109 */
110 in_len = IN_LEN;
111 lzo_memset(in,0,in_len);
112
113 /*
114 * Step 4: compress from 'in' to 'out' with LZO1X-1
115 */
116 r = lzo1x_1_compress(in, in_len, out, &out_len, wrkmem);
117 if (r == LZO_E_OK)
118 printf("compressed %lu bytes into %lu bytes\n",
119 (unsigned long) in_len, (unsigned long) out_len);
120 else
121 {
122 /* this should NEVER happen */
123 printf("internal error - compression failed: %d\n", r);
124 return 2;
125 }
126 /* check for an incompressible block */
127 if (out_len >= in_len)
128 {
129 printf("This block contains incompressible data.\n");
130 return 0;
131 }
132
133 /*
134 * Step 5: decompress again, now going from 'out' to 'in'
135 */
136 new_len = in_len;
137 r = lzo1x_decompress(out, out_len, in, &new_len, NULL);
138 if (r == LZO_E_OK && new_len == in_len)
139 printf("decompressed %lu bytes back into %lu bytes\n",
140 (unsigned long) out_len, (unsigned long) in_len);
141 else
142 {
143 /* this should NEVER happen */
144 printf("internal error - decompression failed: %d\n", r);
145 return 1;
146 }
147
148 lzo_free(wrkmem);
149 lzo_free(out);
150 lzo_free(in);
151 printf("Simple compression test passed.\n");
152 return 0;
153 }
154
155
156 /* vim:set ts=4 sw=4 et: */
157