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
|
/**
* @file byteorder.h
* @brief byte order handling
* @author Christopher Han <xiphux@gmail.com>
*
* Copyright (C) 2005. Licensed under the terms of the
* GNU GPL, v2 or later.
*
* Mac PPC: BIG Endian
* Mac X86: little Endian
*
* Win X86: little Endian
*
* BSD X86: BIG Endian
* Linux X86: BIG Endian
*
* Um... all x86 machines are little endian.
* - cfh
*/
#ifndef BYTEORDER_H
#define BYTEORDER_H
#include <string.h>
/*
* The swabbing stuff looks backwards, but the files
* are _originally_ little endian (win32 x86).
* So in this case little endian is the standard while
* big endian is the exception.
*/
#if defined(__linux__)
#include <byteswap.h>
#if __BYTE_ORDER == __BIG_ENDIAN
#define swabword(w) (bswap_16(w))
#define swabdword(w) (bswap_32(w))
/*
My brother tells me that a C compiler must store floats in memory
by a particular standard, except for the endianness; hence, this
will work on all C compilers.
*/
static inline float swabfloat(float w) {
char octets[4];
char ret_octets[4];
float ret;
memcpy(octets, &w, 4);
ret_octets[0] = octets[3];
ret_octets[1] = octets[2];
ret_octets[2] = octets[1];
ret_octets[3] = octets[0];
memcpy(&ret, ret_octets, 4);
return ret;
}
#else
#define swabword(w) (w)
#define swabdword(w) (w)
#define swabfloat(w) (w)
#endif
#elif defined(__FreeBSD__)
#include <sys/endian.h>
#define swabword(w) (htole16(w))
#define swabdword(w) (htole32(w))
static inline float swabfloat(float w) {
/* compile time assertion to validate sizeof(int) == sizeof(float) */
typedef int sizeof_long_equals_sizeof_float[sizeof(int) == sizeof(float) ? 1 : -1];
int l = swabdword(*(int*)&w);
return *(float*)&l;
}
#elif defined(__APPLE__) && defined(_BIG_ENDIAN)
#include <CoreFoundation/CFByteOrder.h>
#define swabword(w) CFSwapInt32(w)
#define swabdword(w) CFSwapInt64(w)
#define swabfloat(w) (w)
#else
// empty versions for win32
#define swabword(w) (w)
#define swabdword(w) (w)
#define swabfloat(w) (w)
#endif
#endif
|
