Refactor audio buffering API, this should mainly prevent SDL audio driver from allocating memory in the mixer callback.

GpAudioDriver_XAudio2/GpAudioBufferXAudio2.cpp

@@ -0,0 +1,67 @@
+#include "GpAudioBufferXAudio2.h"
+#include "CoreDefs.h"
+#include "GpWindows.h"
+
+#include <malloc.h>
+#include <string.h>
+#include <new>
+
+GpAudioBufferXAudio2 *GpAudioBufferXAudio2::Create(const void *buffer, size_t size)
+{
+	size_t baseSize = sizeof(GpAudioBufferXAudio2);
+	baseSize = baseSize + GP_SYSTEM_MEMORY_ALIGNMENT - 1;
+	baseSize -= baseSize % GP_SYSTEM_MEMORY_ALIGNMENT;
+
+	size_t totalSize = baseSize + size;
+
+	void *storage = _aligned_malloc(totalSize, GP_SYSTEM_MEMORY_ALIGNMENT);
+	if (!storage)
+		return nullptr;
+
+	void *dataPos = static_cast<uint8_t*>(storage) + baseSize;
+
+	memcpy(dataPos, buffer, size);
+	return new (storage) GpAudioBufferXAudio2(dataPos, size);
+}
+
+void GpAudioBufferXAudio2::AddRef()
+{
+	InterlockedIncrement(&m_count);
+}
+
+void GpAudioBufferXAudio2::Release()
+{
+	if (InterlockedDecrement(&m_count) == 0)
+		this->Destroy();
+}
+
+const XAUDIO2_BUFFER *GpAudioBufferXAudio2::GetXA2Buffer() const
+{
+	return &m_xa2Buffer;
+}
+
+GpAudioBufferXAudio2::GpAudioBufferXAudio2(const void *data, size_t size)
+	: m_data(data)
+	, m_size(size)
+	, m_count(1)
+{
+	m_xa2Buffer.Flags = 0;
+	m_xa2Buffer.AudioBytes = static_cast<UINT32>(size);
+	m_xa2Buffer.pAudioData = static_cast<const BYTE*>(data);
+	m_xa2Buffer.PlayBegin = 0;
+	m_xa2Buffer.PlayLength = 0;
+	m_xa2Buffer.LoopBegin = 0;
+	m_xa2Buffer.LoopLength = 0;
+	m_xa2Buffer.LoopCount = 0;
+	m_xa2Buffer.pContext = this;
+}
+
+GpAudioBufferXAudio2::~GpAudioBufferXAudio2()
+{
+}
+
+void GpAudioBufferXAudio2::Destroy()
+{
+	this->~GpAudioBufferXAudio2();
+	_aligned_free(this);
+}