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1 /*
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2 SDL - Simple DirectMedia Layer
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3 Copyright (C) 1997, 1998, 1999, 2000, 2001 Sam Lantinga
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4
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5 This library is free software; you can redistribute it and/or
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6 modify it under the terms of the GNU Library General Public
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7 License as published by the Free Software Foundation; either
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8 version 2 of the License, or (at your option) any later version.
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9
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10 This library is distributed in the hope that it will be useful,
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11 but WITHOUT ANY WARRANTY; without even the implied warranty of
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12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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13 Library General Public License for more details.
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14
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15 You should have received a copy of the GNU Library General Public
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16 License along with this library; if not, write to the Free
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17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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18
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19 Sam Lantinga
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20 slouken@devolution.com
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21 */
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22
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23 #ifdef SAVE_RCSID
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24 static char rcsid =
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25 "@(#) $Id$";
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26 #endif
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27
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28 /* Functions for reading and writing endian-specific values */
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29
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30 #ifndef _SDL_endian_h
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31 #define _SDL_endian_h
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32
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33 /* These functions read and write data of the specified endianness,
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34 dynamically translating to the host machine endianness.
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35
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36 e.g.: If you want to read a 16 bit value on big-endian machine from
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37 an open file containing little endian values, you would use:
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38 value = SDL_ReadLE16(rp);
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39 Note that the read/write functions use SDL_RWops pointers
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40 instead of FILE pointers. This allows you to read and write
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41 endian values from large chunks of memory as well as files
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42 and other data sources.
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43 */
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44
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45 #include <stdio.h>
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46
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47 #include "SDL_types.h"
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48 #include "SDL_rwops.h"
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49 #include "SDL_byteorder.h"
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50
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51 #include "begin_code.h"
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52 /* Set up for C function definitions, even when using C++ */
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53 #ifdef __cplusplus
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54 extern "C" {
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55 #endif
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56
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57 /* The macros used to swap values */
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58 /* Try to use superfast macros on systems that support them */
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59 #ifdef linux
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60 #include <asm/byteorder.h>
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61 #ifdef __arch__swab16
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62 #define SDL_Swap16 __arch__swab16
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63 #endif
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64 #ifdef __arch__swab32
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65 #define SDL_Swap32 __arch__swab32
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66 #endif
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67 #endif /* linux */
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68 /* Use inline functions for compilers that support them, and static
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69 functions for those that do not. Because these functions become
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70 static for compilers that do not support inline functions, this
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71 header should only be included in files that actually use them.
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72 */
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73 #ifndef SDL_Swap16
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74 static __inline__ Uint16 SDL_Swap16(Uint16 D) {
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75 return((D<<8)|(D>>8));
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76 }
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77 #endif
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78 #ifndef SDL_Swap32
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79 static __inline__ Uint32 SDL_Swap32(Uint32 D) {
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80 return((D<<24)|((D<<8)&0x00FF0000)|((D>>8)&0x0000FF00)|(D>>24));
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81 }
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82 #endif
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83 #ifdef SDL_HAS_64BIT_TYPE
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84 #ifndef SDL_Swap64
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85 static __inline__ Uint64 SDL_Swap64(Uint64 val) {
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86 Uint32 hi, lo;
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87
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88 /* Separate into high and low 32-bit values and swap them */
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89 lo = (Uint32)(val&0xFFFFFFFF);
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90 val >>= 32;
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91 hi = (Uint32)(val&0xFFFFFFFF);
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92 val = SDL_Swap32(lo);
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93 val <<= 32;
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94 val |= SDL_Swap32(hi);
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95 return(val);
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96 }
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97 #endif
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98 #else
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99 #ifndef SDL_Swap64
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100 /* This is mainly to keep compilers from complaining in SDL code.
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101 If there is no real 64-bit datatype, then compilers will complain about
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102 the fake 64-bit datatype that SDL provides when it compiles user code.
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103 */
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104 #define SDL_Swap64(X) (X)
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105 #endif
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106 #endif /* SDL_HAS_64BIT_TYPE */
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107
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108
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109 /* Byteswap item from the specified endianness to the native endianness */
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110 #if SDL_BYTEORDER == SDL_LIL_ENDIAN
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111 #define SDL_SwapLE16(X) (X)
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112 #define SDL_SwapLE32(X) (X)
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113 #define SDL_SwapLE64(X) (X)
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114 #define SDL_SwapBE16(X) SDL_Swap16(X)
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115 #define SDL_SwapBE32(X) SDL_Swap32(X)
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116 #define SDL_SwapBE64(X) SDL_Swap64(X)
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117 #else
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118 #define SDL_SwapLE16(X) SDL_Swap16(X)
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119 #define SDL_SwapLE32(X) SDL_Swap32(X)
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120 #define SDL_SwapLE64(X) SDL_Swap64(X)
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121 #define SDL_SwapBE16(X) (X)
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122 #define SDL_SwapBE32(X) (X)
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123 #define SDL_SwapBE64(X) (X)
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124 #endif
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125
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126 /* Read an item of the specified endianness and return in native format */
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127 extern DECLSPEC Uint16 SDL_ReadLE16(SDL_RWops *src);
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128 extern DECLSPEC Uint16 SDL_ReadBE16(SDL_RWops *src);
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129 extern DECLSPEC Uint32 SDL_ReadLE32(SDL_RWops *src);
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130 extern DECLSPEC Uint32 SDL_ReadBE32(SDL_RWops *src);
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131 extern DECLSPEC Uint64 SDL_ReadLE64(SDL_RWops *src);
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132 extern DECLSPEC Uint64 SDL_ReadBE64(SDL_RWops *src);
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133
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134 /* Write an item of native format to the specified endianness */
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135 extern DECLSPEC int SDL_WriteLE16(SDL_RWops *dst, Uint16 value);
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136 extern DECLSPEC int SDL_WriteBE16(SDL_RWops *dst, Uint16 value);
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137 extern DECLSPEC int SDL_WriteLE32(SDL_RWops *dst, Uint32 value);
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138 extern DECLSPEC int SDL_WriteBE32(SDL_RWops *dst, Uint32 value);
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139 extern DECLSPEC int SDL_WriteLE64(SDL_RWops *dst, Uint64 value);
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140 extern DECLSPEC int SDL_WriteBE64(SDL_RWops *dst, Uint64 value);
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141
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142
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143 /* Ends C function definitions when using C++ */
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144 #ifdef __cplusplus
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145 }
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146 #endif
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147 #include "close_code.h"
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148
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149 #endif /* _SDL_endian_h */
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