SDL_endian.h
1
2
/*
SDL - Simple DirectMedia Layer
3
Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002 Sam Lantinga
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with this library; if not, write to the Free
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
Sam Lantinga
20
slouken@libsdl.org
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
*/
#ifdef SAVE_RCSID
static char rcsid =
"@(#) $Id$";
#endif
/* Functions for reading and writing endian-specific values */
#ifndef _SDL_endian_h
#define _SDL_endian_h
/* These functions read and write data of the specified endianness,
dynamically translating to the host machine endianness.
e.g.: If you want to read a 16 bit value on big-endian machine from
an open file containing little endian values, you would use:
value = SDL_ReadLE16(rp);
Note that the read/write functions use SDL_RWops pointers
instead of FILE pointers. This allows you to read and write
endian values from large chunks of memory as well as files
and other data sources.
*/
#include <stdio.h>
#include "SDL_types.h"
#include "SDL_rwops.h"
#include "SDL_byteorder.h"
#include "begin_code.h"
/* Set up for C function definitions, even when using C++ */
#ifdef __cplusplus
extern "C" {
#endif
/* The macros used to swap values */
/* Try to use superfast macros on systems that support them */
#ifdef linux
#include <asm/byteorder.h>
#ifdef __arch__swab16
#define SDL_Swap16 __arch__swab16
#endif
#ifdef __arch__swab32
#define SDL_Swap32 __arch__swab32
#endif
#endif /* linux */
/* Use inline functions for compilers that support them, and static
functions for those that do not. Because these functions become
static for compilers that do not support inline functions, this
header should only be included in files that actually use them.
*/
#ifndef SDL_Swap16
static __inline__ Uint16 SDL_Swap16(Uint16 D) {
return((D<<8)|(D>>8));
}
#endif
#ifndef SDL_Swap32
static __inline__ Uint32 SDL_Swap32(Uint32 D) {
return((D<<24)|((D<<8)&0x00FF0000)|((D>>8)&0x0000FF00)|(D>>24));
}
#endif
#ifdef SDL_HAS_64BIT_TYPE
#ifndef SDL_Swap64
static __inline__ Uint64 SDL_Swap64(Uint64 val) {
Uint32 hi, lo;
/* Separate into high and low 32-bit values and swap them */
lo = (Uint32)(val&0xFFFFFFFF);
val >>= 32;
hi = (Uint32)(val&0xFFFFFFFF);
val = SDL_Swap32(lo);
val <<= 32;
val |= SDL_Swap32(hi);
return(val);
}
#endif
#else
#ifndef SDL_Swap64
/* This is mainly to keep compilers from complaining in SDL code.
If there is no real 64-bit datatype, then compilers will complain about
the fake 64-bit datatype that SDL provides when it compiles user code.
*/
#define SDL_Swap64(X) (X)
#endif
#endif /* SDL_HAS_64BIT_TYPE */
/* Byteswap item from the specified endianness to the native endianness */
#if SDL_BYTEORDER == SDL_LIL_ENDIAN
#define SDL_SwapLE16(X) (X)
#define SDL_SwapLE32(X) (X)
#define SDL_SwapLE64(X) (X)
#define SDL_SwapBE16(X) SDL_Swap16(X)
#define SDL_SwapBE32(X) SDL_Swap32(X)
#define SDL_SwapBE64(X) SDL_Swap64(X)
#else
#define SDL_SwapLE16(X) SDL_Swap16(X)
#define SDL_SwapLE32(X) SDL_Swap32(X)
#define SDL_SwapLE64(X) SDL_Swap64(X)
#define SDL_SwapBE16(X) (X)
#define SDL_SwapBE32(X) (X)
#define SDL_SwapBE64(X) (X)
#endif
/* Read an item of the specified endianness and return in native format */
127
128
129
130
131
132
extern DECLSPEC Uint16 SDLCALL SDL_ReadLE16(SDL_RWops *src);
extern DECLSPEC Uint16 SDLCALL SDL_ReadBE16(SDL_RWops *src);
extern DECLSPEC Uint32 SDLCALL SDL_ReadLE32(SDL_RWops *src);
extern DECLSPEC Uint32 SDLCALL SDL_ReadBE32(SDL_RWops *src);
extern DECLSPEC Uint64 SDLCALL SDL_ReadLE64(SDL_RWops *src);
extern DECLSPEC Uint64 SDLCALL SDL_ReadBE64(SDL_RWops *src);
133
134
/* Write an item of native format to the specified endianness */
135
136
137
138
139
140
extern DECLSPEC int SDLCALL SDL_WriteLE16(SDL_RWops *dst, Uint16 value);
extern DECLSPEC int SDLCALL SDL_WriteBE16(SDL_RWops *dst, Uint16 value);
extern DECLSPEC int SDLCALL SDL_WriteLE32(SDL_RWops *dst, Uint32 value);
extern DECLSPEC int SDLCALL SDL_WriteBE32(SDL_RWops *dst, Uint32 value);
extern DECLSPEC int SDLCALL SDL_WriteLE64(SDL_RWops *dst, Uint64 value);
extern DECLSPEC int SDLCALL SDL_WriteBE64(SDL_RWops *dst, Uint64 value);
141
142
143
144
145
146
147
148
149
/* Ends C function definitions when using C++ */
#ifdef __cplusplus
}
#endif
#include "close_code.h"
#endif /* _SDL_endian_h */