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该实现中创建了两个队列，一个empty队列，用于存放预分配的缓冲区，也就是一个缓存池，另外一个是full队列。实际使用中，写者从empty队列中获取一个队列项，并将数据写入该队列项指定的地址，然后将该队列项放入full队列。读者从full队列中获得一个队列项，然后对这个队列项进行处理，处理完后将这个队列项重新放入empty队列中。

#include <osa_buf.h>
#include <string.h>

int OSA_bufDelete(OSA_BufHndl *hndl)
{
    int status = OSA_SOK;

    if(hndl == NULL)
        return OSA_EFAIL;

    status = OSA_queDelete(&hndl->emptyQue);
    status |= OSA_queDelete(&hndl->fullQue);

    return status;
}

int OSA_bufCreate(OSA_BufHndl *hndl, OSA_BufCreate *bufInit)
{
    int status = OSA_SOK;
    int i;

    if(hndl == NULL || bufInit == NULL)
        return OSA_EFAIL;

    if(bufInit->numBuf > OSA_BUF_NUM_MAX)
        return OSA_EFAIL;

    memset(hndl, 0, sizeof(OSA_BufHndl));

    status = OSA_queCreate(&hndl->emptyQue, bufInit->numBuf);

    if(status != OSA_SOK) {
        OSA_ERROR("OSA_bufCreate() = %d \r\n", status);
        return status;
    }

    status = OSA_queCreate(&hndl->fullQue, bufInit->numBuf);

    if(status != OSA_SOK) {
        OSA_queDelete(&hndl->emptyQue);
        OSA_ERROR("OSA_bufCreate() = %d \r\n", status);
        return status;
    }

    hndl->numBuf = bufInit->numBuf;

    for(i = 0; i < hndl->numBuf; i++) {
        hndl->bufInfo[i].size = 0;
        hndl->bufInfo[i].flags = 0;
        hndl->bufInfo[i].timestamp = 0;
        hndl->bufInfo[i].physAddr = bufInit->bufPhysAddr[i];
        hndl->bufInfo[i].virtAddr = bufInit->bufVirtAddr[i];
        OSA_quePut(&hndl->emptyQue, i, OSA_TIMEOUT_FOREVER);
    }

    return status;
}

int OSA_bufSwitchFull(OSA_BufHndl *hndl, int *bufId)
{
    int status;
    int newBufId;

    status = OSA_bufGetEmpty(hndl, &newBufId, OSA_TIMEOUT_NONE);

    if(status == OSA_SOK) {

        if(*bufId != OSA_BUF_ID_INVALID)
            OSA_bufPutFull(hndl, *bufId);

        *bufId = newBufId;
    }

    return status;
}

int OSA_bufSwitchEmpty(OSA_BufHndl *hndl, int *bufId)
{
    int status;
    int newBufId;

    status = OSA_bufGetFull(hndl, &newBufId, OSA_TIMEOUT_NONE);

    if(status == OSA_SOK) {

        if(*bufId != OSA_BUF_ID_INVALID)
            OSA_bufPutEmpty(hndl, *bufId);

        *bufId = newBufId;
    }

    return status;
}