summaryrefslogtreecommitdiff
path: root/src/lzo_util.c
blob: 1e4a9e3303f771ee2d8a605334c62b492e476ec4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
/* lzo_util.c -- utilities for the LZO library

   This file is part of the LZO real-time data compression library.

   Copyright (C) 2011 Markus Franz Xaver Johannes Oberhumer
   Copyright (C) 2010 Markus Franz Xaver Johannes Oberhumer
   Copyright (C) 2009 Markus Franz Xaver Johannes Oberhumer
   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/
 */


#include "lzo_conf.h"


/***********************************************************************
//
************************************************************************/

/* If you use the LZO library in a product, I would appreciate that you
 * keep this copyright string in the executable of your product.
.*/

static const char __lzo_copyright[] =
#if !defined(__LZO_IN_MINLZO)
    /* save space as some people want a really small decompressor */
    LZO_VERSION_STRING;
#else
    "\r\n\n"
    "LZO data compression library.\n"
    "$Copyright: LZO Copyright (C) 1996-2011 Markus Franz Xaver Johannes Oberhumer\n"
    "<markus@oberhumer.com>\n"
    "http://www.oberhumer.com $\n\n"
    "$Id: LZO version: v" LZO_VERSION_STRING ", " LZO_VERSION_DATE " $\n"
    "$Info: " LZO_INFO_STRING " $\n";
#endif


LZO_PUBLIC(const lzo_bytep)
lzo_copyright(void)
{
#if (LZO_OS_DOS16 && LZO_CC_TURBOC)
    return (lzo_voidp) __lzo_copyright;
#else
    return (const lzo_bytep) __lzo_copyright;
#endif
}

LZO_PUBLIC(unsigned)
lzo_version(void)
{
    return LZO_VERSION;
}

LZO_PUBLIC(const char *)
lzo_version_string(void)
{
    return LZO_VERSION_STRING;
}

LZO_PUBLIC(const char *)
lzo_version_date(void)
{
    return LZO_VERSION_DATE;
}

LZO_PUBLIC(const lzo_charp)
_lzo_version_string(void)
{
    return LZO_VERSION_STRING;
}

LZO_PUBLIC(const lzo_charp)
_lzo_version_date(void)
{
    return LZO_VERSION_DATE;
}


/***********************************************************************
// adler32 checksum
// adapted from free code by Mark Adler <madler@alumni.caltech.edu>
// see http://www.zlib.org/
************************************************************************/

#define LZO_BASE 65521u /* largest prime smaller than 65536 */
#define LZO_NMAX 5552
/* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */

#define LZO_DO1(buf,i)  s1 += buf[i]; s2 += s1
#define LZO_DO2(buf,i)  LZO_DO1(buf,i); LZO_DO1(buf,i+1);
#define LZO_DO4(buf,i)  LZO_DO2(buf,i); LZO_DO2(buf,i+2);
#define LZO_DO8(buf,i)  LZO_DO4(buf,i); LZO_DO4(buf,i+4);
#define LZO_DO16(buf,i) LZO_DO8(buf,i); LZO_DO8(buf,i+8);

LZO_PUBLIC(lzo_uint32)
lzo_adler32(lzo_uint32 adler, const lzo_bytep buf, lzo_uint len)
{
    lzo_uint32 s1 = adler & 0xffff;
    lzo_uint32 s2 = (adler >> 16) & 0xffff;
    unsigned k;

    if (buf == NULL)
        return 1;

    while (len > 0)
    {
        k = len < LZO_NMAX ? (unsigned) len : LZO_NMAX;
        len -= k;
        if (k >= 16) do
        {
            LZO_DO16(buf,0);
            buf += 16;
            k -= 16;
        } while (k >= 16);
        if (k != 0) do
        {
            s1 += *buf++;
            s2 += s1;
        } while (--k > 0);
        s1 %= LZO_BASE;
        s2 %= LZO_BASE;
    }
    return (s2 << 16) | s1;
}

#undef LZO_DO1
#undef LZO_DO2
#undef LZO_DO4
#undef LZO_DO8
#undef LZO_DO16


/*
vi:ts=4:et
*/