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
|
/*
* Copyright (C) 2013 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef LE_FX_ENGINE_COMMON_CORE_BYTE_SWAPPER_H_
#define LE_FX_ENGINE_COMMON_CORE_BYTE_SWAPPER_H_
#include <stdio.h>
#include <string.h>
#include "common/core/basic_types.h"
#include "common/core/os.h"
namespace le_fx {
namespace arch {
inline bool IsLittleEndian(void) {
int16 word = 1;
char *cp = reinterpret_cast<char *>(&word);
return cp[0] != 0;
}
inline bool IsBigEndian(void) {
return !IsLittleEndian();
}
template <typename T, unsigned int kValSize>
struct ByteSwapper {
static T Swap(const T &val) {
T new_val = val;
char *first = &new_val, *last = first + kValSize - 1, x;
for (; first < last; ++first, --last) {
x = *last;
*last = *first;
*first = x;
}
return new_val;
}
};
template <typename T>
struct ByteSwapper<T, 1> {
static T Swap(const T &val) {
return val;
}
};
template <typename T>
struct ByteSwapper<T, 2> {
static T Swap(const T &val) {
T new_val;
const char *o = (const char *)&val;
char *p = reinterpret_cast<char *>(&new_val);
p[0] = o[1];
p[1] = o[0];
return new_val;
}
};
template <typename T>
struct ByteSwapper<T, 4> {
static T Swap(const T &val) {
T new_val;
const char *o = (const char *)&val;
char *p = reinterpret_cast<char *>(&new_val);
p[0] = o[3];
p[1] = o[2];
p[2] = o[1];
p[3] = o[0];
return new_val;
}
};
template <typename T>
struct ByteSwapper<T, 8> {
static T Swap(const T &val) {
T new_val = val;
const char *o = (const char *)&val;
char *p = reinterpret_cast<char *>(&new_val);
p[0] = o[7];
p[1] = o[6];
p[2] = o[5];
p[3] = o[4];
p[4] = o[3];
p[5] = o[2];
p[6] = o[1];
p[7] = o[0];
return new_val;
}
};
template <typename T>
T SwapBytes(const T &val, bool force_swap) {
if (force_swap) {
#if !defined(LE_FX__NEED_BYTESWAP)
return ByteSwapper<T, sizeof(T)>::Swap(val);
#else
return val;
#endif // !LE_FX_NEED_BYTESWAP
} else {
#if !defined(LE_FX_NEED_BYTESWAP)
return val;
#else
return ByteSwapper<T, sizeof(T)>::Swap(val);
#endif // !LE_FX_NEED_BYTESWAP
}
}
template <typename T>
const T *SwapBytes(const T *vals, unsigned int num_items, bool force_swap) {
if (force_swap) {
#if !defined(LE_FX_NEED_BYTESWAP)
T *writeable_vals = const_cast<T *>(vals);
for (unsigned int i = 0; i < num_items; i++) {
writeable_vals[i] = ByteSwapper<T, sizeof(T)>::Swap(vals[i]);
}
return writeable_vals;
#else
return vals;
#endif // !LE_FX_NEED_BYTESWAP
} else {
#if !defined(LE_FX_NEED_BYTESWAP)
return vals;
#else
T *writeable_vals = const_cast<T *>(vals);
for (unsigned int i = 0; i < num_items; i++) {
writeable_vals[i] = ByteSwapper<T, sizeof(T)>::Swap(vals[i]);
}
return writeable_vals;
#endif // !LE_FX_NEED_BYTESWAP
}
}
} // namespace arch
} // namespace le_fx
#endif // LE_FX_ENGINE_COMMON_CORE_BYTE_SWAPPER_H_
|
