47 lines
1.4 KiB
C
47 lines
1.4 KiB
C
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/****************************************************************************
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Copyright(c) 2019 by Aerospace C.Power (Chongqing) Microelectronics. ALL RIGHTS RESERVED.
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This Information is proprietary to Aerospace C.Power (Chongqing) Microelectronics and MAY NOT
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be copied by any method or incorporated into another program without
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the express written consent of Aerospace C.Power. This Information or any portion
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thereof remains the property of Aerospace C.Power. The Information contained herein
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is believed to be accurate and Aerospace C.Power assumes no responsibility or
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liability for its use in any way and conveys no license or title under
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any patent or copyright and makes no representation or warranty that this
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Information is free from patent or copyright infringement.
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****************************************************************************/
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#include "iot_checksum.h"
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uint16_t iot_getcksum(uint8_t *ptr, uint32_t size)
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{
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uint32_t index = 0;
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uint32_t cksum = 0;
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if ((NULL == ptr) || (0 == size))
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{
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return 0;
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}
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while(index < (size - 1))
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{
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cksum += *(ptr + index + 1);
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cksum += *(ptr + index) << 8;
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index += 2;
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}
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if (size % 2)
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{
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cksum += ((uint16_t)*(ptr + index) << 8) & 0xFF00;
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}
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while(cksum > 0xffff)
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{
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cksum = (cksum >> 16) + (cksum & 0xffff);
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}
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return (uint16_t)(~cksum);
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}
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