如何将缓冲区内容复制到结构中定义的另一个缓冲区 [英] How to copy buffer contents to another buffer which is defined in structure

问题描述

我创建了一个缓冲区...



char buffer [8] =mindflow;



和我试图将这个缓冲区内容复制到另一个缓冲区buffer_p.count中，该缓冲区是在嵌套结构中定义的....



/ * DMA回调函数处理P到U转移的产生事件。 * /

无效

CyFxSlFifoPtoUDmaCallback（

CyU3PDmaChannel * chHandle，

CyU3PDmaCbType_t类型，

CyU3PDmaCBInput_t *输入



）

{

CyU3PReturnStatus_t status = CY_U3P_SUCCESS;



if（type == CY_U3P_DMA_CB_PROD_EVENT）

{

/ *这是向CPU发出的生产事件通知。收到每个缓冲区后收到此通知

*。除非明确提交，否则不会发送缓冲区

* out。如果

*是总线重置/ usb断开连接或者有任何应用程序错误，则调用将失败。 * /

char buffer [9] =MIND FLOW;



status = CyU3PDmaChannelCommitBuffer（chHandle，input-> buffer_p.count ，0）;



if（status！= CY_U3P_SUCCESS）

{

CyU3PDebugPrint（4，CyU3PDmaChannelCommitBuffer失败，错误代码=％d \ n，状态）;

}



/ *递增计数器。 * /

glDMATxCount ++;

}

}



我尝试过：

I have created a buffer...

char buffer[8]="mindflow";

and i tried to copy this buffer contents into another buffer buffer_p.count which is defined in nested structure....

/* DMA callback function to handle the produce events for P to U transfers. */
void
CyFxSlFifoPtoUDmaCallback (
CyU3PDmaChannel *chHandle,
CyU3PDmaCbType_t type,
CyU3PDmaCBInput_t *input

)
{
CyU3PReturnStatus_t status = CY_U3P_SUCCESS;

if (type == CY_U3P_DMA_CB_PROD_EVENT)
{
/* This is a produce event notification to the CPU. This notification is
* received upon reception of every buffer. The buffer will not be sent
* out unless it is explicitly committed. The call shall fail if there
* is a bus reset / usb disconnect or if there is any application error. */
char buffer[9]= "MIND FLOW";

status = CyU3PDmaChannelCommitBuffer (chHandle, input->buffer_p.count, 0);

if (status != CY_U3P_SUCCESS)
{
CyU3PDebugPrint (4, "CyU3PDmaChannelCommitBuffer failed, Error code = %d\n", status);
}

/* Increment the counter. */
glDMATxCount++;
}
}

What I have tried:

/* DMA callback function to handle the produce events for P to U transfers. */
void
CyFxSlFifoPtoUDmaCallback (
        CyU3PDmaChannel   *chHandle,
        CyU3PDmaCbType_t  type,
        CyU3PDmaCBInput_t *input

        )
{
    CyU3PReturnStatus_t status = CY_U3P_SUCCESS;

    if (type == CY_U3P_DMA_CB_PROD_EVENT)
    {
        /* This is a produce event notification to the CPU. This notification is 
         * received upon reception of every buffer. The buffer will not be sent
         * out unless it is explicitly committed. The call shall fail if there
         * is a bus reset / usb disconnect or if there is any application error. */
    	char buffer[9]= "MIND FLOW";

        status = CyU3PDmaChannelCommitBuffer (chHandle, input->buffer_p.count, 0);

        if (status != CY_U3P_SUCCESS)
        {
            CyU3PDebugPrint (4, "CyU3PDmaChannelCommitBuffer failed, Error code = %d\n", status);
        }

        /* Increment the counter. */
        glDMATxCount++;
    }
}

推荐答案

您可以使用memcpy [ ^ ]用于此目的的功能。



请注意您首先要分配（可能）目标缓冲区的内存（然后你必须释放动态分配的内存）。

You might use the memcpy[^] function for the purpose.

Please note you have first to allocate (possibly dynamic) memory for the destination buffer (and then you have to release the dynamically allocated memory).

回答的声明输入 - > buffer_p [。必须知道计数] 应该从哪里复制多少字节。请注意，我已将 .count 放入括号中，因为名称表示它是计数/大小值而不是缓冲区。



好​​的，我搜索了它并在 https://github.com/nickdademo/cypress-fx3-sdk-linux/blob/master/firmware/u3p_firmware/inc/cyu3dma.h [ ^ ]：

To answer that the declaration of input->buffer_p[.count] must be known and how many bytes should be copied from where to where. Note that I have put the .count into brackets because the name indicates that it is a count/size value and not a buffer.

Okay, I searched for it and found it at https://github.com/nickdademo/cypress-fx3-sdk-linux/blob/master/firmware/u3p_firmware/inc/cyu3dma.h[^]:

typedef struct CyU3PDmaBuffer_t
{
    uint8_t *buffer;    /**< Pointer to the data buffer. */
    uint16_t count;     /**< Byte count of valid data in buffer. */
    uint16_t size;      /**< Actual size of the buffer in bytes. Should be a multiple of 16. */
    uint16_t status;    /**< Buffer status. This is a four bit data field defined by 
                             CY_U3P_DMA_BUFFER_STATUS_MASK. This holds information like
                             whether the buffer is occupied, whether the buffer holds the
                             end of packet and whether the buffer encountered a DMA error. */
} CyU3PDmaBuffer_t;

/** \brief DMA channel callback input.
    **Description**\n
    This data structure is used to provide event specific information when a DMA callback
    is called. This structure is defined as a union to facilitate future updates to the
    DMA manager.
    **\see
    *\see CyU3PDmaBuffer_t
    *\see CyU3PDmaCallback_t
 */
typedef union CyU3PDmaCBInput_t
{
    CyU3PDmaBuffer_t buffer_p;  /**< Data about the DMA buffer that caused the callback to be called. */
} CyU3PDmaCBInput_t;

据说你可以用

According to that you can copy the data to your buffer with

memcpy(buffer, input->buffer_p.buffer, input->buffer_p.count);

前提是你的缓冲区足够大（size> = 输入 - > buffer_p.count ）。



将数据复制到 input-> buffer_p ，反方向复制并在检查后相应地设置其他结构成员（ count ， status ）足够的大小。

provided that your buffer is large enough (size >= input->buffer_p.count).

To copy data to the input->buffer_p, copy in the reverse direction and set the other structure members accordingly (count, status) after checking for sufficient size.

uint16_t bufSize = sizeof(buffer); // or whatever the actual size is
if (bufSize <= input->buffer_p.size)
{
    input->buffer_p.count = bufSize;
    input->buffer_p.status = theStatus; // 
    memcpy(input->buffer_p.buffer, buffer, bufSize);
}

但你必须遵守SDK的规格

[/ EDIT]



我不确定这里发出回调的方向​​。但你应该知道什么时候做这种低级别的东西。

But you have to comply with the specifications of the SDK
[/EDIT]

I'm not sure for which direction the callback is issued here. But you should know when doing such low level stuff.

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