FUNCTIONS

1. SDL_Swap64
2. SDL_SwapLE16
3. SDL_SwapLE32
4. SDL_SwapLE64
5. SDL_SwapBE16
6. SDL_SwapBE32
7. SDL_SwapBE64
8. SDL_SwapLE16
9. SDL_SwapLE32
10. SDL_SwapLE64
11. SDL_SwapBE16
12. SDL_SwapBE32
13. SDL_SwapBE64

   1 /*
   2     SDL - Simple DirectMedia Layer
   3     Copyright (C) 1997, 1998, 1999, 2000, 2001  Sam Lantinga
   4 
   5     This library is free software; you can redistribute it and/or
   6     modify it under the terms of the GNU Library General Public
   7     License as published by the Free Software Foundation; either
   8     version 2 of the License, or (at your option) any later version.
   9 
  10     This library is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13     Library General Public License for more details.
  14 
  15     You should have received a copy of the GNU Library General Public
  16     License along with this library; if not, write to the Free
  17     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18 
  19     Sam Lantinga
  20     slouken@devolution.com
  21 */
  23 #ifdef SAVE_RCSID
  24 static char rcsid =
  25  "@(#) $Id: SDL_endian.h,v 1.4.2.3 2001/02/17 01:45:30 hercules Exp $";
  26 #endif
  28 /* Functions for reading and writing endian-specific values */
  30 #ifndef _SDL_endian_h
  31 #define _SDL_endian_h
  33 /* These functions read and write data of the specified endianness, 
  34    dynamically translating to the host machine endianness.
  35 
  36    e.g.: If you want to read a 16 bit value on big-endian machine from
  37          an open file containing little endian values, you would use:
  38                 value = SDL_ReadLE16(rp);
  39          Note that the read/write functions use SDL_RWops pointers
  40          instead of FILE pointers.  This allows you to read and write
  41          endian values from large chunks of memory as well as files 
  42          and other data sources.
  43 */
  45 #include <stdio.h>
  47 #include "SDL_types.h"
  48 #include "SDL_rwops.h"
  49 #include "SDL_byteorder.h"
  51 #include "begin_code.h"
  52 /* Set up for C function definitions, even when using C++ */
  53 #ifdef __cplusplus
  54 extern "C" {
  55 #endif
  57 /* The macros used to swap values */
  58 /* Try to use superfast macros on systems that support them */
  59 #ifdef linux
  60 #include <asm/byteorder.h>
  61 #ifdef __arch__swab16
  62 #define SDL_Swap16  __arch__swab16
  63 #endif
  64 #ifdef __arch__swab32
  65 #define SDL_Swap32  __arch__swab32
  66 #endif
  67 #endif /* linux */
  68 /* Use inline functions for compilers that support them, and static
  69    functions for those that do not.  Because these functions become
  70    static for compilers that do not support inline functions, this
  71    header should only be included in files that actually use them.
  72 */
  73 #ifndef SDL_Swap16
  74 static __inline__ Uint16 SDL_Swap16(Uint16 D) {
  75         return((D<<8)|(D>>8));
  76 }
  77 #endif
  78 #ifndef SDL_Swap32
  79 static __inline__ Uint32 SDL_Swap32(Uint32 D) {
  80         return((D<<24)|((D<<8)&0x00FF0000)|((D>>8)&0x0000FF00)|(D>>24));
  81 }
  82 #endif
  83 #ifdef SDL_HAS_64BIT_TYPE
  84 #ifndef SDL_Swap64
  85 static __inline__ Uint64 SDL_Swap64(Uint64 val) {
  86         Uint32 hi, lo;
  88         /* Separate into high and low 32-bit values and swap them */
  89         lo = (Uint32)(val&0xFFFFFFFF);
  90         val >>= 32;
  91         hi = (Uint32)(val&0xFFFFFFFF);
  92         val = SDL_Swap32(lo);
  93         val <<= 32;
  94         val |= SDL_Swap32(hi);
  95         return(val);
  96 }
  97 #endif
  98 #else
  99 #ifndef SDL_Swap64
 100 /* This is mainly to keep compilers from complaining in SDL code.
 101    If there is no real 64-bit datatype, then compilers will complain about
 102    the fake 64-bit datatype that SDL provides when it compiles user code.
 103 */
 104 #define SDL_Swap64(X)   (X)
     /* [<][>][^][v][top][bottom][index][help] */
 105 #endif
 106 #endif /* SDL_HAS_64BIT_TYPE */
 109 /* Byteswap item from the specified endianness to the native endianness */
 110 #if SDL_BYTEORDER == SDL_LIL_ENDIAN
 111 #define SDL_SwapLE16(X) (X)
     /* [<][>][^][v][top][bottom][index][help] */
 112 #define SDL_SwapLE32(X) (X)
     /* [<][>][^][v][top][bottom][index][help] */
 113 #define SDL_SwapLE64(X) (X)
     /* [<][>][^][v][top][bottom][index][help] */
 114 #define SDL_SwapBE16(X) SDL_Swap16(X)
     /* [<][>][^][v][top][bottom][index][help] */
 115 #define SDL_SwapBE32(X) SDL_Swap32(X)
     /* [<][>][^][v][top][bottom][index][help] */
 116 #define SDL_SwapBE64(X) SDL_Swap64(X)
     /* [<][>][^][v][top][bottom][index][help] */
 117 #else
 118 #define SDL_SwapLE16(X) SDL_Swap16(X)
     /* [<][>][^][v][top][bottom][index][help] */
 119 #define SDL_SwapLE32(X) SDL_Swap32(X)
     /* [<][>][^][v][top][bottom][index][help] */
 120 #define SDL_SwapLE64(X) SDL_Swap64(X)
     /* [<][>][^][v][top][bottom][index][help] */
 121 #define SDL_SwapBE16(X) (X)
     /* [<][>][^][v][top][bottom][index][help] */
 122 #define SDL_SwapBE32(X) (X)
     /* [<][>][^][v][top][bottom][index][help] */
 123 #define SDL_SwapBE64(X) (X)
     /* [<][>][^][v][top][bottom][index][help] */
 124 #endif
 126 /* Read an item of the specified endianness and return in native format */
 127 extern DECLSPEC Uint16 SDL_ReadLE16(SDL_RWops *src);
 128 extern DECLSPEC Uint16 SDL_ReadBE16(SDL_RWops *src);
 129 extern DECLSPEC Uint32 SDL_ReadLE32(SDL_RWops *src);
 130 extern DECLSPEC Uint32 SDL_ReadBE32(SDL_RWops *src);
 131 extern DECLSPEC Uint64 SDL_ReadLE64(SDL_RWops *src);
 132 extern DECLSPEC Uint64 SDL_ReadBE64(SDL_RWops *src);
 134 /* Write an item of native format to the specified endianness */
 135 extern DECLSPEC int SDL_WriteLE16(SDL_RWops *dst, Uint16 value);
 136 extern DECLSPEC int SDL_WriteBE16(SDL_RWops *dst, Uint16 value);
 137 extern DECLSPEC int SDL_WriteLE32(SDL_RWops *dst, Uint32 value);
 138 extern DECLSPEC int SDL_WriteBE32(SDL_RWops *dst, Uint32 value);
 139 extern DECLSPEC int SDL_WriteLE64(SDL_RWops *dst, Uint64 value);
 140 extern DECLSPEC int SDL_WriteBE64(SDL_RWops *dst, Uint64 value);
 143 /* Ends C function definitions when using C++ */
 144 #ifdef __cplusplus
 145 }
 146 #endif
 147 #include "close_code.h"
 149 #endif /* _SDL_endian_h */