util_buffer.c
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/**
******************************************************************************
* @file util_buffer.c
* @brief The file defines buffer related functions, including initialize, put data to buffer,
* get data from buffer and get unused count of bytes of buffer.
*
* @copyright (c) 2021 DJI. All rights reserved.
*
* All information contained herein is, and remains, the property of DJI.
* The intellectual and technical concepts contained herein are proprietary
* to DJI and may be covered by U.S. and foreign patents, patents in process,
* and protected by trade secret or copyright law. Dissemination of this
* information, including but not limited to data and other proprietary
* material(s) incorporated within the information, in any form, is strictly
* prohibited without the express written consent of DJI.
*
* If you receive this source code without DJI’s authorization, you may not
* further disseminate the information, and you must immediately remove the
* source code and notify DJI of its removal. DJI reserves the right to pursue
* legal actions against you for any loss(es) or damage(s) caused by your
* failure to do so.
*
******************************************************************************
*/
/* Includes ------------------------------------------------------------------*/
#include "util_buffer.h"
#include <string.h>
#include "util_misc.h"
/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
/* Exported variables --------------------------------------------------------*/
/* Private function prototypes -----------------------------------------------*/
/* Private functions ---------------------------------------------------------*/
/**
* @brief Cut buffer size to power of 2, in order to increase the convenience of get and put operating of buffer.
* @param bufSize Original buffer size.
* @return Buffer size after handling.
*/
static uint16_t UtilBuffer_CutBufSizeToPowOfTwo(uint16_t bufSize)
{
uint16_t i = 0;
while ((1 << (++i)) <= bufSize);
return (uint16_t) (1 << (--i));
}
/* Exported functions --------------------------------------------------------*/
/**
* @brief Buffer initialization.
* @param pthis Pointer to buffer structure.
* @param pBuf Pointer to data buffer.
* @param bufSize Size of data buffer.
* @return None.
*/
void UtilBuffer_Init(T_UtilBuffer *pthis, uint8_t *pBuf, uint16_t bufSize)
{
pthis->readIndex = 0;
pthis->writeIndex = 0;
pthis->bufferPtr = pBuf;
pthis->bufferSize = UtilBuffer_CutBufSizeToPowOfTwo(bufSize);
}
/**
* @brief Put a block of data into buffer.
* @param pthis Pointer to buffer structure.
* @param pData Pointer to data to be stored.
* @param dataLen Length of data to be stored.
* @return Length of data to be stored.
*/
uint16_t UtilBuffer_Put(T_UtilBuffer *pthis, const uint8_t *pData, uint16_t dataLen)
{
uint16_t writeUpLen;
dataLen = USER_UTIL_MIN(dataLen, (uint16_t) (pthis->bufferSize - pthis->writeIndex + pthis->readIndex));
//fill up data
writeUpLen = USER_UTIL_MIN(dataLen, (uint16_t) (pthis->bufferSize - (pthis->writeIndex & (pthis->bufferSize - 1))));
memcpy(pthis->bufferPtr + (pthis->writeIndex & (pthis->bufferSize - 1)), pData, writeUpLen);
//fill begin data
memcpy(pthis->bufferPtr, pData + writeUpLen, dataLen - writeUpLen);
pthis->writeIndex += dataLen;
return dataLen;
}
/**
* @brief Get a block of data from buffer.
* @param pthis Pointer to buffer structure.
* @param pData Pointer to data to be read.
* @param dataLen Length of data to be read.
* @return Length of data to be read.
*/
uint16_t UtilBuffer_Get(T_UtilBuffer *pthis, uint8_t *pData, uint16_t dataLen)
{
uint16_t readUpLen;
dataLen = USER_UTIL_MIN(dataLen, (uint16_t) (pthis->writeIndex - pthis->readIndex));
//get up data
readUpLen = USER_UTIL_MIN(dataLen, (uint16_t) (pthis->bufferSize - (pthis->readIndex & (pthis->bufferSize - 1))));
memcpy(pData, pthis->bufferPtr + (pthis->readIndex & (pthis->bufferSize - 1)), readUpLen);
//get begin data
memcpy(pData + readUpLen, pthis->bufferPtr, dataLen - readUpLen);
pthis->readIndex += dataLen;
return dataLen;
}
/**
* @brief Get unused size of buffer.
* @param pthis Pointer to buffer structure.
* @return Unused size of buffer.
*/
uint16_t UtilBuffer_GetUnusedSize(T_UtilBuffer *pthis)
{
return (uint16_t) (pthis->bufferSize - pthis->writeIndex + pthis->readIndex);
}