ring buffer

rungbuf.c

typedef struct _SListBuffer {
	struct _SRingBuffer * next;
	void *		pData;
	size_t		DataSize;
	long int	Status;
}SListBuffer;
typedef struct _SRingBuffer {
	SListBuffer *	ListHead;
	SListBuffer *	ListBottom;
	unsigned int 	Length;
	unsigned int	Dummy;
	pthread_mutex_t	MutexLocker;
}SRingBuffer;

typedef enum _EDRingBufferReturnCode{
	D_RING_BUFFER_MEMORY_ERROR	= -16,
	D_RING_BUFFER_MUTEX_ERROR,
	D_RING_BUFFER_PARAM_ERROR,
	D_RING_BUFFER_SUCCESS		= 0,
}EDRingBufferReturnCode;

int RingBufferInitialize(SRingBuffer ** ppRingBuffer){
	SRingBuffer *	pRingBuffer	= NULL;
	if(!pRingBuffer)
	{
		return D_RING_BUFFER_PARAM_ERROR;
	}
	pRingBuffer = *ppRingBuffer;
	if(pRingBuffer)
	{
		return D_RING_BUFFER_PARAM_ERROR;
	}
	pRingBuffer = (SRingBuffer*) malloc (sizeof(SRingBuffer));
	if(pRingBuffer){
		return D_RING_BUFFER_MEMORY_ERROR;
	}
	memset(pRingBuffer,0x00,sizeof(SRingBuffer));
	pthread_mutex_init(&(pRingBuffer->MutexLocker), NULL);
	if(pthread_mutex_lock(&(pRingBuffer->MutexLocker)) != 0)
	{
		free(pRingBuffer);
		return D_RING_BUFFER_MUTEX_ERROR;
	}
	*ppRingBuffer = pRingBuffer;
	pthread_mutex_unlock(&(pRingBuffer->MutexLocker));
	return D_RING_BUFFER_SUCCESS;
}
int RingBufferDestroy(SRingBuffer ** ppRingBuffer)
{
	SRingBuffer *	pRingBuffer	= NULL;
	SListBuffer *	pListCurrent= NULL;
	SListBuffer *	pListBuffer	= NULL;
	if(!pRingBuffer)
	{
		return D_RING_BUFFER_PARAM_ERROR;
	}
	pRingBuffer = *ppRingBuffer;
	if(!pRingBuffer)
	{
		/* すでに解放済みなのでエラーとしない */
		return D_RING_BUFFER_SUCCESS;
	}
	pthread_mutex_lock(&(pRingBuffer->MutexLocker));
	*ppRingBuffer = NULL;
	/* リング構造を破棄し、リスト構造にする(NULL終端) */
	pListCurrent = pRingBuffer->ListBottom->next;
	pRingBuffer->ListBottom->next = NULL;
	while(pListCurrent){
		pListBuffer = pListCurrent;
		if(pListCurrent->pData){
			free(pListCurrent->pData);
			pListCurrent->pData = NULL;
		}
		pListCurrent->DataSize = 0;
		pListCurrent = pListCurrent->next;
		free(pListBuffer);
		pListBuffer = NULL;
	}
	pthread_mutex_unlock(&(pRingBuffer->MutexLocker));
	pthread_mutex_destroy(&(pRingBuffer->MutexLocker));
	free(pRingBuffer);
	return D_RING_BUFFER_SUCCESS;
}

int RingBufferAllocate(SRingBuffer ** ppRingBuffer,size_t zSize)
{
	SRingBuffer *	pRingBuffer	= NULL;
	SListBuffer *	pListBuffer	= NULL;
	void *			pvData		= NULL;
	if(!pRingBuffer)
	{
		return D_RING_BUFFER_PARAM_ERROR;
	}
	pRingBuffer = *ppRingBuffer;
	if(!pRingBuffer)
	{
		return D_RING_BUFFER_PARAM_ERROR;
	}
	pvData		=	(void *)		malloc (zSize);
	pListBuffer	=	(SListBuffer*)	malloc (sizeof(SListBuffer));
	if(!pvData || !pListBuffer)
	{
		if(pvData)
		{
			free(pvData);
		}
		if(pListBuffer)
		{
			free(pListBuffer);
		}
		return D_RING_BUFFER_MEMORY_ERROR;
	}
	/* 初期化 */
	memset(pvData		, 0x00, zSize				);
	memset(pListBuffer	, 0x00, sizeof(SListBuffer)	);
	/* あらかじめリスト情報を更新しておく */
	pListBuffer->pData		= pvData;
	pListBuffer->DataSize	= zSize;
	/* 管理情報と連結する */
	/* !!Mutex LOCK */
	if(pthread_mutex_lock(&(pRingBuffer->MutexLocker)) != 0)
	{
		free(pvData);
		free(pListBuffer);
		return D_RING_BUFFER_MUTEX_ERROR;
	}
	if(!*ppRingBuffer)
	{
		/* 通常ありえない */
		free(pvData);
		free(pListBuffer);
		return D_RING_BUFFER_MEMORY_ERROR;
	}
	if(pRingBuffer->ListBottom)
	{
		pListBuffer->next	= pRingBuffer->ListBottom->next;
	} else {
		pRingBuffer->ListBottom = pListBuffer;
	}
	pRingBuffer->ListBottom->next = pListBuffer;
		
	(pRingBuffer->Length)++;
	/* !!Mutex UNlock */
	pthread_mutex_unlock(&(pRingBuffer->MutexLocker));
	
	return D_RING_BUFFER_SUCCESS;
}