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/* |
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SDL - Simple DirectMedia Layer |
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Copyright (C) 1997, 1998, 1999, 2000, 2001 Sam Lantinga |
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|
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This library is free software; you can redistribute it and/or |
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modify it under the terms of the GNU Library General Public |
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License as published by the Free Software Foundation; either |
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version 2 of the License, or (at your option) any later version. |
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|
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This library is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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Library General Public License for more details. |
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|
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You should have received a copy of the GNU Library General Public |
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License along with this library; if not, write to the Free |
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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|
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Sam Lantinga |
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slouken@devolution.com |
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*/ |
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|
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#ifdef SAVE_RCSID |
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static char rcsid = |
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"@(#) $Id: SDL_endian.h,v 1.4.2.3 2001/02/17 01:45:30 hercules Exp $"; |
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#endif |
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|
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/* Functions for reading and writing endian-specific values */ |
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|
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#ifndef _SDL_endian_h |
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#define _SDL_endian_h |
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|
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/* These functions read and write data of the specified endianness, |
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dynamically translating to the host machine endianness. |
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|
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e.g.: If you want to read a 16 bit value on big-endian machine from |
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an open file containing little endian values, you would use: |
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value = SDL_ReadLE16(rp); |
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Note that the read/write functions use SDL_RWops pointers |
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instead of FILE pointers. This allows you to read and write |
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endian values from large chunks of memory as well as files |
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and other data sources. |
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*/ |
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|
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#include <stdio.h> |
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|
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#include "SDL_types.h" |
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#include "SDL_rwops.h" |
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#include "SDL_byteorder.h" |
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|
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#include "begin_code.h" |
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/* Set up for C function definitions, even when using C++ */ |
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#ifdef __cplusplus |
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extern "C" { |
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#endif |
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|
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/* The macros used to swap values */ |
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/* Try to use superfast macros on systems that support them */ |
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#ifdef linux |
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#include <asm/byteorder.h> |
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#ifdef __arch__swab16 |
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#define SDL_Swap16 __arch__swab16 |
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#endif |
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#ifdef __arch__swab32 |
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#define SDL_Swap32 __arch__swab32 |
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#endif |
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#endif /* linux */ |
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/* Use inline functions for compilers that support them, and static |
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functions for those that do not. Because these functions become |
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static for compilers that do not support inline functions, this |
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header should only be included in files that actually use them. |
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*/ |
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#ifndef SDL_Swap16 |
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static __inline__ Uint16 SDL_Swap16(Uint16 D) { |
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return((D<<8)|(D>>8)); |
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} |
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#endif |
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#ifndef SDL_Swap32 |
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static __inline__ Uint32 SDL_Swap32(Uint32 D) { |
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return((D<<24)|((D<<8)&0x00FF0000)|((D>>8)&0x0000FF00)|(D>>24)); |
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} |
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#endif |
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#ifdef SDL_HAS_64BIT_TYPE |
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#ifndef SDL_Swap64 |
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static __inline__ Uint64 SDL_Swap64(Uint64 val) { |
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Uint32 hi, lo; |
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|
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/* Separate into high and low 32-bit values and swap them */ |
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lo = (Uint32)(val&0xFFFFFFFF); |
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val >>= 32; |
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hi = (Uint32)(val&0xFFFFFFFF); |
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val = SDL_Swap32(lo); |
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val <<= 32; |
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val |= SDL_Swap32(hi); |
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return(val); |
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} |
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#endif |
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#else |
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#ifndef SDL_Swap64 |
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/* This is mainly to keep compilers from complaining in SDL code. |
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If there is no real 64-bit datatype, then compilers will complain about |
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the fake 64-bit datatype that SDL provides when it compiles user code. |
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*/ |
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#define SDL_Swap64(X) (X) |
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#endif |
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#endif /* SDL_HAS_64BIT_TYPE */ |
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|
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|
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/* Byteswap item from the specified endianness to the native endianness */ |
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#if SDL_BYTEORDER == SDL_LIL_ENDIAN |
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#define SDL_SwapLE16(X) (X) |
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#define SDL_SwapLE32(X) (X) |
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#define SDL_SwapLE64(X) (X) |
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#define SDL_SwapBE16(X) SDL_Swap16(X) |
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#define SDL_SwapBE32(X) SDL_Swap32(X) |
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#define SDL_SwapBE64(X) SDL_Swap64(X) |
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#else |
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#define SDL_SwapLE16(X) SDL_Swap16(X) |
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#define SDL_SwapLE32(X) SDL_Swap32(X) |
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#define SDL_SwapLE64(X) SDL_Swap64(X) |
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#define SDL_SwapBE16(X) (X) |
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#define SDL_SwapBE32(X) (X) |
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#define SDL_SwapBE64(X) (X) |
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#endif |
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|
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/* Read an item of the specified endianness and return in native format */ |
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extern DECLSPEC Uint16 SDL_ReadLE16(SDL_RWops *src); |
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extern DECLSPEC Uint16 SDL_ReadBE16(SDL_RWops *src); |
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extern DECLSPEC Uint32 SDL_ReadLE32(SDL_RWops *src); |
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extern DECLSPEC Uint32 SDL_ReadBE32(SDL_RWops *src); |
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extern DECLSPEC Uint64 SDL_ReadLE64(SDL_RWops *src); |
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extern DECLSPEC Uint64 SDL_ReadBE64(SDL_RWops *src); |
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|
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/* Write an item of native format to the specified endianness */ |
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extern DECLSPEC int SDL_WriteLE16(SDL_RWops *dst, Uint16 value); |
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extern DECLSPEC int SDL_WriteBE16(SDL_RWops *dst, Uint16 value); |
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extern DECLSPEC int SDL_WriteLE32(SDL_RWops *dst, Uint32 value); |
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extern DECLSPEC int SDL_WriteBE32(SDL_RWops *dst, Uint32 value); |
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extern DECLSPEC int SDL_WriteLE64(SDL_RWops *dst, Uint64 value); |
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extern DECLSPEC int SDL_WriteBE64(SDL_RWops *dst, Uint64 value); |
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|
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|
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/* Ends C function definitions when using C++ */ |
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#ifdef __cplusplus |
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} |
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#endif |
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#include "close_code.h" |
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|
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#endif /* _SDL_endian_h */ |
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