checksum.h
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1 #ifdef __cplusplus
2 extern "C" {
3 #endif
4 
5 #ifndef _CHECKSUM_H_
6 #define _CHECKSUM_H_
7 
8 // Visual Studio versions before 2010 don't have stdint.h, so we just error out.
9 #if (defined _MSC_VER) && (_MSC_VER < 1600)
10 #error "The C-MAVLink implementation requires Visual Studio 2010 or greater"
11 #endif
12 
13 #include <stdint.h>
14 
21 #define X25_INIT_CRC 0xffff
22 #define X25_VALIDATE_CRC 0xf0b8
23 
24 #ifndef HAVE_CRC_ACCUMULATE
25 
34 static inline void crc_accumulate(uint8_t data, uint16_t *crcAccum)
35 {
36  /*Accumulate one byte of data into the CRC*/
37  uint8_t tmp;
38 
39  tmp = data ^ (uint8_t)(*crcAccum &0xff);
40  tmp ^= (tmp<<4);
41  *crcAccum = (*crcAccum>>8) ^ (tmp<<8) ^ (tmp <<3) ^ (tmp>>4);
42 }
43 #endif
44 
45 
51 static inline void crc_init(uint16_t* crcAccum)
52 {
53  *crcAccum = X25_INIT_CRC;
54 }
55 
56 
64 static inline uint16_t crc_calculate(const uint8_t* pBuffer, uint16_t length)
65 {
66  uint16_t crcTmp;
67  crc_init(&crcTmp);
68  while (length--) {
69  crc_accumulate(*pBuffer++, &crcTmp);
70  }
71  return crcTmp;
72 }
73 
74 
84 static inline void crc_accumulate_buffer(uint16_t *crcAccum, const char *pBuffer, uint16_t length)
85 {
86  const uint8_t *p = (const uint8_t *)pBuffer;
87  while (length--) {
88  crc_accumulate(*p++, crcAccum);
89  }
90 }
91 
92 #endif /* _CHECKSUM_H_ */
93 
94 #ifdef __cplusplus
95 }
96 #endif
#define X25_INIT_CRC
Definition: checksum.h:21
static uint16_t crc_calculate(const uint8_t *pBuffer, uint16_t length)
Calculates the X.25 checksum on a byte buffer.
Definition: checksum.h:64
static void crc_accumulate(uint8_t data, uint16_t *crcAccum)
Accumulate the X.25 CRC by adding one char at a time.
Definition: checksum.h:34
static void crc_init(uint16_t *crcAccum)
Initiliaze the buffer for the X.25 CRC.
Definition: checksum.h:51
static void crc_accumulate_buffer(uint16_t *crcAccum, const char *pBuffer, uint16_t length)
Accumulate the X.25 CRC by adding an array of bytes.
Definition: checksum.h:84


rosflight_firmware
Author(s): Daniel Koch , James Jackson
autogenerated on Thu Oct 24 2019 03:17:18