/*

SDL - Simple DirectMedia Layer

Copyright (C) 1997-2006 Sam Lantinga

This library is free software; you can redistribute it and/or

modify it under the terms of the GNU Lesser General Public

License as published by the Free Software Foundation; either

version 2.1 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

Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public

License along with this library; if not, write to the Free Software

Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

Sam Lantinga

slouken@libsdl.org

*/

/**

* \file SDL_atomic.h

*

*/

#ifndef _SDL_atomic_h_

#define _SDL_atomic_h_

#include "SDL_stdinc.h"

#include "SDL_platform.h"

#include "begin_code.h"

/* Set up for C function definitions, even when using C++ */

#ifdef __cplusplus

/* *INDENT-OFF* */

extern "C" {

/* *INDENT-ON* */

#endif

/**

* \def SDL_AtomicBusyWait32 (ptr)

*

* \brief Implements a simple busy wait for use with

* SDL_AtomicTestThenSet and SDL_AtomicClear.

*

* Note: This can be an infinite loop.

*

*/

#define SDL_AtomicBusyWait32(ptr) \

{ \

while (!SDL_AtomicTestThenSet32(ptr) \

{ \

}; \

};

/**

* \def SDL_AtomicWait32(ptr)

*

* \brief A safer way to wait for a test-then-set lock to be cleared.

*

* This assumes that the SDL_Sleep(0) call acts as a thread_yeild

* operation.

*

*/

#define SDL_AtomicWait32(ptr) \

{ \

while (!SDL_AtomicTestThenSet32(ptr) \

{ \

SDL_Sleep(0); \

}; \

};

/**

* \def SDL_AtomicBusyWait64(ptr)

*

* \brief 64 bit version of busy wait

*

* \sa SDL_AtomicBusyWait32

*/

#define SDL_AtomicBusyWait64(ptr) \

{ \

while (!SDL_AtomicTestThenSet64(ptr) \

{ \

}; \

};

/**

* \def SDL_AtomicWait64(ptr)

*

* \brief 64 bit version of SDL_AtomicWait32

*

* \sa SDL_AtomicWait32

*/

#define SDL_AtomicWait64(ptr) \

{ \

while (!SDL_AtomicTestThenSet64(ptr) \

{ \

SDL_Sleep(0); \

}; \

};

/**

* \fn int SDL_AtomicExchange32(Uint32 * ptr, Uint32 value)

*

* \brief Atomically exchange two 32 bit values.

*

* \return the value point to by ptr.

*

* \param ptr points to the value to be fetched from *ptr.

* \param value is value to be stored at *ptr.

*

* The current value stored at *ptr is returned and it is replaced

* with value. This function can be used to implement SDL_TestThenSet.

*

*/

extern DECLSPEC Uint32 SDLCALL SDL_AtomicExchange32(Uint32 * ptr, Uint32 value);

/**

* \fn int SDL_AtomicCompareThenSet32(Uint32 * ptr, Uint32 oldvalue, Uint32 newvalue)

*

* \brief If *ptr == oldvalue then replace the contents of *ptr by new value.

*

* \return true if the newvalue was stored.

*

* \param *ptr is the value to be compared and replaced.

* \param oldvalue is value to be compared to *ptr.

* \param newvalue is value to be stored at *ptr.

*

*/

extern DECLSPEC SDL_bool SDLCALL SDL_AtomicCompareThenSet32(Uint32 * ptr,

Uint32 oldvalue, Uint32 newvalue);

/**

* \fn SDL_bool SDL_AtomicTestThenSet32(Uint32 * ptr);

*

* \brief Check to see if *ptr == 0 and set it to non-zero.

*

* \return SDL_True if the value pointed to by ptr was zero and

* SDL_False if it was not zero

*

* \param ptr points to the value to be tested and set.

*

*/

extern DECLSPEC SDL_bool SDLCALL SDL_AtomicTestThenSet32(Uint32 * ptr);

/**

* \fn void SDL_AtomicClear32(Uint32 * ptr);

*

* \brief set the value pointed to by ptr to be zero.

*

* \param ptr address of the value to be set to zero

*

*/

extern DECLSPEC void SDLCALL SDL_AtomicClear32(Uint32 * ptr);

/**

* \fn Uint32 SDL_AtomicFetchThenIncrement32(Uint32 * ptr);

*

* \brief fetch the current value of *ptr and then increment that

* value in place.

*

* \return the value before it was incremented.

*

* \param ptr address of the value to fetch and increment

*

*/

extern DECLSPEC Uint32 SDLCALL SDL_AtomicFetchThenIncrement32(Uint32 * ptr);

/**

* \fn Uint32 SDL_AtomicFetchThenDecrement32(Uint32 * ptr);

*

* \brief fetch *ptr and then decrement the value in place.

*

* \return the value before it was decremented.

*

* \param ptr address of the value to fetch and drement

*

*/

extern DECLSPEC Uint32 SDLCALL SDL_AtomicFetchThenDecrement32(Uint32 * ptr);

/**

* \fn Uint32 SDL_AtomicFetchThenAdd32(Uint32 * ptr, Uint32 value);

*

* \brief fetch the current value at ptr and then add value to *ptr.

*

* \return *ptr before the addition took place.

*

* \param ptr the address of data we are changing.

* \param value the value to add to *ptr.

*

*/

extern DECLSPEC Uint32 SDLCALL SDL_AtomicFetchThenAdd32(Uint32 * ptr, Uint32 value);

/**

* \fn Uint32 SDL_AtomicFetchThenSubtract32(Uint32 * ptr, Uint32 value);

*

* \brief Fetch *ptr and then subtract value from it.

*

* \return *ptr before the subtraction took place.

*

* \param ptr the address of the data being changed.

* \param value the value to subtract from *ptr.

*

*/

extern DECLSPEC Uint32 SDLCALL SDL_AtomicFetchThenSubtract32(Uint32 * ptr, Uint32 value);

/**

* \fn Uint32 SDL_AtomicIncrementThenFetch32(Uint32 * ptr);

*

* \brief Add one to the data pointed to by ptr and return that value.

*

* \return the incremented value.

*

* \param ptr address of the data to increment.

*

*/

extern DECLSPEC Uint32 SDLCALL SDL_AtomicIncrementThenFetch32(Uint32 * ptr);

/**

* \fn Uint32 SDL_AtomicDecrementThenFetch32(Uint32 * ptr);

*

* \brief Subtract one from data pointed to by ptr and return the new value.

*

* \return The decremented value.

*

* \param ptr The address of the data to decrement.

*

*/

extern DECLSPEC Uint32 SDLCALL SDL_AtomicDecrementThenFetch32(Uint32 * ptr);

/**

* \fn Uint32 SDL_AtomicAddThenFetch32(Uint32 * ptr, Uint32 value);

*

* \brief Add value to the data pointed to by ptr and return result.

*

* \return The sum of *ptr and value.

*

* \param ptr The address of the data to be modified.

* \param value The value to be added.

*

*/

extern DECLSPEC Uint32 SDLCALL SDL_AtomicAddThenFetch32(Uint32 * ptr, Uint32 value);

/**

* \fn Uint32 SDL_AtomicSubtractThenFetch32(Uint32 * ptr, Uint32 value);

*

* \brief Subtract value from the data pointed to by ptr and return the result.

*

* \return the difference between *ptr and value.

*

* \param ptr The address of the data to be modified.

* \param value The value to be subtracted.

*

*/

extern DECLSPEC Uint32 SDLCALL SDL_AtomicSubtractThenFetch32(Uint32 * ptr, Uint32 value);

#ifdef SDL_HAS_64BIT_TYPE

extern DECLSPEC Uint64 SDLCALL SDL_AtomicExchange64(Uint64 * ptr, Uint64 value);

extern DECLSPEC SDL_bool SDLCALL SDL_AtomicCompareThenSet64(Uint64 * ptr,

Uint64 oldvalue, Uint64 newvalue);

extern DECLSPEC SDL_bool SDLCALL SDL_AtomicTestThenSet64(Uint64 * ptr);

extern DECLSPEC void SDLCALL SDL_AtomicClear64(Uint64 * ptr);

extern DECLSPEC Uint64 SDLCALL SDL_AtomicFetchThenIncrement64(Uint64 * ptr);

extern DECLSPEC Uint64 SDLCALL SDL_AtomicFetchThenDecrement64(Uint64 * ptr);

extern DECLSPEC Uint64 SDLCALL SDL_AtomicFetchThenAdd64(Uint64 * ptr, Uint64 value);

extern DECLSPEC Uint64 SDLCALL SDL_AtomicFetchThenSubtract64(Uint64 * ptr, Uint64 value);

extern DECLSPEC Uint64 SDLCALL SDL_AtomicIncrementThenFetch64(Uint64 * ptr);

extern DECLSPEC Uint64 SDLCALL SDL_AtomicDecrementThenFetch64(Uint64 * ptr);

extern DECLSPEC Uint64 SDLCALL SDL_AtomicAddThenFetch64(Uint64 * ptr, Uint64 value);

extern DECLSPEC Uint64 SDLCALL SDL_AtomicSubtractThenFetch64(Uint64 * ptr, Uint64 value);

#endif

/* Ends C function definitions when using C++ */

#ifdef __cplusplus

/* *INDENT-OFF* */

}

/* *INDENT-ON* */

#endif

#include "close_code.h"

#endif /* _SDL_atomic_h_ */

/* vi: set ts=4 sw=4 expandtab: */