12.1. crc — Cyclic Redundancy Checks¶
Source code: src/hash/crc.h, src/hash/crc.c
Test code: tst/hash/crc/main.c
Test coverage: src/hash/crc.c
Defines
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CRC_8_POLYNOMIAL_8_5_4_0¶ The polynomial
x^8 + x^5 + x^4 + x^0.
Functions
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uint32_t
crc_32(uint32_t crc, const void *buf_p, size_t size)¶ Calculate a 32 bits crc using the polynomial
x^32+x^26+x^23+x^22+x^16+x^12+x^11+x^10+x^8+x^7+x^5+x^4+x^2+x^1+x^0.- Return
- Calculated crc.
- Parameters
crc: Initial crc. Often 0x00000000.buf_p: Buffer to calculate crc of.size: Size of the buffer.
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uint16_t
crc_ccitt(uint16_t crc, const void *buf_p, size_t size)¶ Calculate a 16 bits crc using the CCITT algorithm (polynomial
x^16+x^12+x^5+x^1).- Return
- Calculated crc.
- Parameters
crc: Initial crc. Should be 0xffff for CCITT.buf_p: Buffer to calculate crc of.size: Size of the buffer.
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uint16_t
crc_xmodem(uint16_t crc, const void *buf_p, size_t size)¶ Calculate a 16 bits crc using the XModem algorithm (polynomial
x^16+x^12+x^5+x^1).- Return
- Calculated crc.
- Parameters
crc: Initial crc. Should be 0x0000 for XModem.buf_p: Buffer to calculate crc of.size: Size of the buffer.
-
uint8_t
crc_7(const void *buf_p, size_t size)¶ Calculate a 8 bits crc using the CRC-7 algorithm (polynomial
x^7+x^3+1).- Return
- Calculated crc.
- Parameters
buf_p: Buffer to calculate crc of.size: Size of the buffer.
-
uint8_t
crc_8(uint8_t crc, uint8_t polynomial, const void *buf_p, size_t size)¶ Calculate a 8 bits crc using given polynomial.
- Return
- Calculated crc.
- Parameters
crc: Initial crc. Must be 0x00 on first call.polynimial: CRC polynomial.buf_p: Buffer to calculate crc of.size: Size of the buffer.