Mercurial > sdl-ios-xcode
diff include/SDL_endian.h @ 0:74212992fb08
Initial revision
author | Sam Lantinga <slouken@lokigames.com> |
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date | Thu, 26 Apr 2001 16:45:43 +0000 |
parents | |
children | b8688cfdc232 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/include/SDL_endian.h Thu Apr 26 16:45:43 2001 +0000 @@ -0,0 +1,149 @@ +/* + SDL - Simple DirectMedia Layer + Copyright (C) 1997, 1998, 1999, 2000, 2001 Sam Lantinga + + 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 + slouken@devolution.com +*/ + +#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 */ +extern DECLSPEC Uint16 SDL_ReadLE16(SDL_RWops *src); +extern DECLSPEC Uint16 SDL_ReadBE16(SDL_RWops *src); +extern DECLSPEC Uint32 SDL_ReadLE32(SDL_RWops *src); +extern DECLSPEC Uint32 SDL_ReadBE32(SDL_RWops *src); +extern DECLSPEC Uint64 SDL_ReadLE64(SDL_RWops *src); +extern DECLSPEC Uint64 SDL_ReadBE64(SDL_RWops *src); + +/* Write an item of native format to the specified endianness */ +extern DECLSPEC int SDL_WriteLE16(SDL_RWops *dst, Uint16 value); +extern DECLSPEC int SDL_WriteBE16(SDL_RWops *dst, Uint16 value); +extern DECLSPEC int SDL_WriteLE32(SDL_RWops *dst, Uint32 value); +extern DECLSPEC int SDL_WriteBE32(SDL_RWops *dst, Uint32 value); +extern DECLSPEC int SDL_WriteLE64(SDL_RWops *dst, Uint64 value); +extern DECLSPEC int SDL_WriteBE64(SDL_RWops *dst, Uint64 value); + + +/* Ends C function definitions when using C++ */ +#ifdef __cplusplus +} +#endif +#include "close_code.h" + +#endif /* _SDL_endian_h */