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
|
/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program 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.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
// Based on eos' math code
#ifndef COMMON_MATH_H
#define COMMON_MATH_H
#include "common/scummsys.h"
#ifdef _MSC_VER
// HACK:
// intrin.h on MSVC includes setjmp.h, which will fail compiling due to our
// forbidden symbol colde. Since we also can not assure that defining
// FORBIDDEN_SYMBOL_EXCEPTION_setjmp and FORBIDDEN_SYMBOL_EXCEPTION_longjmp
// will actually allow the symbols, since forbidden.h might be included
// earlier already we need to undefine them here...
#undef setjmp
#undef longjmp
#include <intrin.h>
// ...and redefine them here so no code can actually use it.
// This could be resolved by including intrin.h on MSVC in scummsys.h before
// the forbidden.h include. This might make sense, in case we use MSVC
// extensions like _BitScanReverse in more places. But for now this hack should
// be ok...
#ifndef FORBIDDEN_SYMBOL_EXCEPTION_setjmp
#undef setjmp
#define setjmp(a) FORBIDDEN_SYMBOL_REPLACEMENT
#endif
#ifndef FORBIDDEN_SYMBOL_EXCEPTION_longjmp
#undef longjmp
#define longjmp(a,b) FORBIDDEN_SYMBOL_REPLACEMENT
#endif
#endif
#ifndef FLT_MIN
#define FLT_MIN 1E-37
#endif
#ifndef FLT_MAX
#define FLT_MAX 1E+37
#endif
namespace Common {
/** A complex number. */
struct Complex {
float re, im;
};
#if GCC_ATLEAST(3, 4)
inline int intLog2(uint32 v) {
// This is a slightly optimized implementation of log2 for natural numbers
// targeting gcc. It also saves some binary size over our fallback
// implementation, since it does not need any table.
if (v == 0)
return -1;
else
// This is really "sizeof(unsigned int) * CHAR_BIT - 1" but using 8
// instead of CHAR_BIT is sane enough and it saves us from including
// limits.h
return (sizeof(unsigned int) * 8 - 1) - __builtin_clz(v);
}
#elif defined(_MSC_VER)
inline int intLog2(uint32 v) {
unsigned long result = 0;
unsigned char nonZero = _BitScanReverse(&result, v);
// _BitScanReverse stores the position of the MSB set in case its result
// is non zero, thus we can just return it as is.
return nonZero ? result : -1;
}
#else
// See http://graphics.stanford.edu/~seander/bithacks.html#IntegerLogLookup
static const char LogTable256[256] = {
#define LT(n) n, n, n, n, n, n, n, n, n, n, n, n, n, n, n, n
-1, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3,
LT(4), LT(5), LT(5), LT(6), LT(6), LT(6), LT(6),
LT(7), LT(7), LT(7), LT(7), LT(7), LT(7), LT(7), LT(7)
};
inline int intLog2(uint32 v) {
register uint32 t, tt;
if ((tt = v >> 16))
return (t = tt >> 8) ? 24 + LogTable256[t] : 16 + LogTable256[tt];
else
return (t = v >> 8) ? 8 + LogTable256[t] : LogTable256[v];
}
#endif
inline float rad2deg(float rad) {
return rad * 180.0f / (float)M_PI;
}
inline float deg2rad(float deg) {
return deg * (float)M_PI / 180.0f;
}
} // End of namespace Common
#endif // COMMON_MATH_H
|
