Mercurial > sdl-ios-xcode
annotate src/main/symbian/EKA2/vectorbuffer.cpp @ 4216:5b99971a27b4 SDL-1.2
Fixed bug #698
Hans de Goede 2009-02-13 01:10:52 PST
Since the new "glitch free" version of pulseaudio (used in Fedora 10 amongst
others), the sound of SDL using apps (like a simple playmus call) has been
crackling.
While looking in to fixing this I noticed that the current pulseaudio code in
SDL uses pa_simple. However pa_simple uses a thread to pump pulseaudio events
and ipc, given that SDL already has its own thread for audio handling this is
clearly suboptimal, leading to unnecessary context switching IPC, etc. Also
pa_simple does not allow one to implement the WaitAudio() callback for SDL
audiodrivers properly.
Given that my work is mostly a rewrite (although some original pieces remain)
I'm attaching the new .c and .h file, as that is easier to review then the huge
diff.
Let me know if you also want the diff.
This new version has the following features:
-no longer use an additional thread next to the SDL sound thread
-do not crackle with glitch free audio
-when used with a newer pulse, which does glitch free audio, the total latency
is
the same as with the alsa driver
-proper WaitAudio() implementation, saving another mixlen worth of latency
-adds a WaitDone() implementation
This patch has been written in consultancy with Lennart Poetering (the
pulseaudio author) and has been reviewed by him for correct use of the pa API.
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Mon, 21 Sep 2009 09:27:08 +0000 |
| parents | e85e65aec22f |
| children |
| rev | line source |
|---|---|
| 3975 | 1 /* |
| 2 vectorbuffer.cpp | |
| 3 yet another circle buffer | |
| 4 | |
| 5 Markus Mertama | |
| 6 */ | |
| 7 | |
| 8 #include"vectorbuffer.h" | |
| 9 | |
| 10 | |
| 11 | |
| 12 void VectorPanic(TInt aErr, TInt aLine) | |
| 13 { | |
| 14 TBuf<64> b; | |
| 15 b.Format(_L("vector buffer at % d "), aLine); | |
| 16 User::Panic(b, aErr); | |
| 17 } | |
| 18 | |
| 19 void TNodeBuffer::TNode::Terminator(TNodeBuffer::TNode* aNode) | |
| 20 { | |
| 21 Mem::Copy(iSucc, &aNode, sizeof(TNode*)); | |
| 22 } | |
| 23 | |
| 24 TInt TNodeBuffer::TNode::Size() const | |
| 25 { | |
| 26 return reinterpret_cast<const TUint8*>(iSucc) - Ptr(); | |
| 27 } | |
| 28 | |
| 29 const TUint8* TNodeBuffer::TNode::Ptr() const | |
| 30 { | |
| 31 return reinterpret_cast<const TUint8*>(this) + sizeof(TNode); | |
| 32 } | |
| 33 | |
| 34 TNodeBuffer::TNode* TNodeBuffer::TNode::Empty(TUint8* aBuffer) | |
| 35 { | |
| 36 TNode* node = reinterpret_cast<TNode*>(aBuffer); | |
| 37 node->iSucc = node + 1; | |
| 38 return node; | |
| 39 } | |
| 40 | |
| 41 TNodeBuffer::TNode* TNodeBuffer::TNode::New(TNode* aPred, const TDesC8& aData) | |
| 42 { | |
| 43 TNode* node = aPred->Size() == 0 ? aPred : aPred->iSucc; | |
| 44 | |
| 45 | |
| 46 TUint8* start = reinterpret_cast<TUint8*>(node) + sizeof(TNode); | |
| 47 node->iSucc = reinterpret_cast<TNode*>(start + aData.Size()); | |
| 48 node->iSucc->iSucc = NULL; //terminator | |
| 49 | |
| 50 __ASSERT_DEBUG(node->Size() == aData.Size(), VECPANIC(KErrCorrupt)); | |
| 51 | |
| 52 Mem::Copy(start, aData.Ptr(), aData.Size()); | |
| 53 return node; | |
| 54 } | |
| 55 | |
| 56 | |
| 57 | |
| 58 | |
| 59 | |
| 60 | |
| 61 | |
| 62 |