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/*
SuperCollider real time audio synthesis system
Copyright (c) 2002 James McCartney. All rights reserved.
http://www.audiosynth.com
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef _MsgFifo_
#define _MsgFifo_
#ifdef SC_DARWIN
# include <CoreServices/CoreServices.h>
#endif
/////////////////////////////////////////////////////////////////////
template <class MsgType, int N>
class MsgFifo
{
public:
MsgFifo()
: mReadHead(0), mWriteHead(0), mFreeHead(0)
{}
void MakeEmpty() { mFreeHead = mReadHead = mWriteHead; }
bool IsEmpty() { return mReadHead == mWriteHead; }
bool HasData() { return mReadHead != mWriteHead; }
bool NeedsFree() { return mFreeHead != mReadHead; }
bool Write(MsgType& data)
{
unsigned int next = NextPos(mWriteHead);
if (next == mFreeHead) return false; // fifo is full
mItems[next] = data;
#ifdef SC_DARWIN
// we don't really need a compare and swap, but this happens to call
// the PowerPC memory barrier instruction lwsync.
CompareAndSwap(mWriteHead, next, &mWriteHead);
#elif defined SC_WIN32
InterlockedExchange(reinterpret_cast<volatile LONG*>(&mWriteHead),next);
#else
mWriteHead = next;
#endif
return true;
}
void Perform() // get next and advance
{
while (HasData()) {
unsigned int next = NextPos(mReadHead);
mItems[next].Perform();
#ifdef SC_DARWIN
// we don't really need a compare and swap, but this happens to call
// the PowerPC memory barrier instruction lwsync.
CompareAndSwap(mReadHead, next, &mReadHead);
#elif defined SC_WIN32
InterlockedExchange(reinterpret_cast<volatile LONG*>(&mReadHead),next);
#else
mReadHead = next;
#endif
}
}
void Free() // reclaim messages
{
while (NeedsFree()) {
unsigned int next = NextPos(mFreeHead);
mItems[next].Free();
#ifdef SC_DARWIN
// we don't really need a compare and swap, but this happens to call
// the PowerPC memory barrier instruction lwsync.
CompareAndSwap(mFreeHead, next, &mFreeHead);
#elif defined SC_WIN32
InterlockedExchange(reinterpret_cast<volatile LONG*>(&mFreeHead),next);
#else
mFreeHead = next;
#endif
}
}
private:
int NextPos(int inPos) { return (inPos + 1) & (N - 1); }
#ifdef SC_DARWIN
UInt32 mReadHead, mWriteHead, mFreeHead;
#else
volatile unsigned int mReadHead, mWriteHead, mFreeHead;
#endif
MsgType mItems[N];
};
/////////////////////////////////////////////////////////////////////
template <class MsgType, int N>
class MsgFifoNoFree
{
public:
MsgFifoNoFree()
: mReadHead(0), mWriteHead(0)
{
}
void MakeEmpty() { mReadHead = mWriteHead; }
bool IsEmpty() { return mReadHead == mWriteHead; }
bool HasData() { return mReadHead != mWriteHead; }
bool Write(MsgType& data)
{
unsigned int next = NextPos(mWriteHead);
if (next == mReadHead) return false; // fifo is full
mItems[next] = data;
#ifdef SC_DARWIN
// we don't really need a compare and swap, but this happens to call
// the PowerPC memory barrier instruction lwsync.
CompareAndSwap(mWriteHead, next, &mWriteHead);
#elif defined SC_WIN32
InterlockedExchange(reinterpret_cast<volatile LONG*>(&mWriteHead),next);
#else
mWriteHead = next;
#endif
return true;
}
void Perform() // get next and advance
{
while (HasData()) {
unsigned int next = NextPos(mReadHead);
mItems[next].Perform();
#ifdef SC_DARWIN
// we don't really need a compare and swap, but this happens to call
// the PowerPC memory barrier instruction lwsync.
CompareAndSwap(mReadHead, next, &mReadHead);
#elif defined SC_WIN32
InterlockedExchange(reinterpret_cast<volatile LONG*>(&mReadHead),next);
#else
mReadHead = next;
#endif
}
}
private:
int NextPos(int inPos) { return (inPos + 1) & (N - 1); }
#ifdef SC_DARWIN
UInt32 mReadHead, mWriteHead;
#else
volatile unsigned int mReadHead, mWriteHead;
#endif
MsgType mItems[N];
};
/////////////////////////////////////////////////////////////////////
#endif
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