crc.h File Reference

CRC update routines (ARC, BinHex, CCITT, CCITT32, Kermit, ZIP). More...

#include <stddef.h>
#include <stdint.h>

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Macros
#define	JUNO_ARC_CRC_INIT   (0)
	Initial seed for CRC-16/ARC (IBM-16) computations.
#define	JUNO_BINHEX_CRC_INIT   (0)
	Initial seed for BinHex 16-bit CRC computations.
#define	JUNO_CCITT_CRC_INIT   (-1)
	Initial seed for CRC-16/CCITT computations (0xFFFF).
#define	JUNO_CCITT32_CRC_INIT   (-1)
	Initial seed for 32-bit CCITT-style CRC computations (0xFFFFFFFF).
#define	JUNO_KERMIT_CRC_INIT   (0)
	Initial seed for CRC-16/KERMIT computations.
#define	JUNO_ZIP_CRC_INIT   (-1)
	Initial seed for ZIP/PKZIP CRC-32 computations (0xFFFFFFFF).
Internal masks (implementation detail)
Bit masks used by table-driven CRC update routines.
#define	M1_16   0xff
#define	M2_16   0xff00
#define	M1_32   0xffffffff
#define	M2_32   0xffffff00

Functions
uint16_t	Juno_CrcArcUpdate (uint16_t iCrc, const void *pcData, size_t zDataSize)
	Update ARC CRC with new data.
uint16_t	Juno_CrcBinhexUpdate (uint16_t iCrc, const void *pcData, size_t zDataSize)
	Update BinHex CRC with new data.
uint16_t	Juno_CrcCcittUpdate (uint16_t iCrc, const void *pcData, size_t zDataSize)
	Update CCITT CRC (16-bit) with new data.
uint32_t	Juno_CrcCcitt32Update (uint32_t iCrc, const void *pcData, size_t zDataSize)
	Update CCITT32 CRC (32-bit) with new data.
uint16_t	Juno_CrcKermitUpdate (uint16_t iCrc, const void *pcData, size_t zDataSize)
	Update Kermit CRC with new data.
uint32_t	Juno_CrcZipUpdate (uint32_t iCrc, const void *pcData, size_t zDataSize)
	Update ZIP CRC (CRC-32) with new data.

Detailed Description

CRC update routines (ARC, BinHex, CCITT, CCITT32, Kermit, ZIP).

Macro Definition Documentation

JUNO_ARC_CRC_INIT

#define JUNO_ARC_CRC_INIT   (0)

Initial seed for CRC-16/ARC (IBM-16) computations.

Expands to 0 (all zeros). Use as the first iCrc value when starting a new ARC CRC computation.

JUNO_BINHEX_CRC_INIT

#define JUNO_BINHEX_CRC_INIT   (0)

Initial seed for BinHex 16-bit CRC computations.

Expands to 0 (all zeros). Use as the first iCrc value for BinHex.

JUNO_CCITT32_CRC_INIT

#define JUNO_CCITT32_CRC_INIT   (-1)

Initial seed for 32-bit CCITT-style CRC computations (0xFFFFFFFF).

Expands to -1 (all ones) as a C integer literal; when passed to the 32-bit function parameter it yields 0xFFFFFFFF. Use as the first iCrc value when starting a new CCITT32 computation.

JUNO_CCITT_CRC_INIT

#define JUNO_CCITT_CRC_INIT   (-1)

Initial seed for CRC-16/CCITT computations (0xFFFF).

Expands to -1 (all ones) as a C integer literal; when passed to the 16-bit function parameter it yields 0xFFFF. Use as the first iCrc value when starting a new CCITT CRC computation.

JUNO_KERMIT_CRC_INIT

#define JUNO_KERMIT_CRC_INIT   (0)

Initial seed for CRC-16/KERMIT computations.

Expands to 0 (all zeros). Use as the first iCrc value for Kermit.

JUNO_ZIP_CRC_INIT

#define JUNO_ZIP_CRC_INIT   (-1)

Initial seed for ZIP/PKZIP CRC-32 computations (0xFFFFFFFF).

Expands to -1 (all ones) as a C integer literal; when passed to the 32-bit function parameter it yields 0xFFFFFFFF. Use as the first iCrc value when starting a new ZIP CRC computation.

M1_16

#define M1_16   0xff

Low byte mask for 16-bit CRC.

M1_32

#define M1_32   0xffffffff

Low word mask for 32-bit CRC.

M2_16

#define M2_16   0xff00

High byte mask for 16-bit CRC.

M2_32

#define M2_32   0xffffff00

High word mask for 32-bit CRC.

Function Documentation

Juno_CrcArcUpdate()

uint16_t Juno_CrcArcUpdate	(	uint16_t	iCrc,
		const void *	pcData,
		size_t	zDataSize
	)

Update ARC CRC with new data.

Parameters

iCrc	Running CRC value (use JUNO_ARC_CRC_INIT for first chunk).
pcData	Pointer to data buffer (can be NULL when zDataSize is 0).
zDataSize	Size of data buffer in bytes.

Returns

Updated CRC value; returns 0 when pcData is NULL or zDataSize is 0.

Juno_CrcBinhexUpdate()

uint16_t Juno_CrcBinhexUpdate	(	uint16_t	iCrc,
		const void *	pcData,
		size_t	zDataSize
	)

Update BinHex CRC with new data.

Parameters

iCrc	Running CRC value (use JUNO_BINHEX_CRC_INIT initially).
pcData	Pointer to data buffer (can be NULL when zDataSize is 0).
zDataSize	Size of data buffer in bytes.

Returns

Updated CRC value; returns 0 when pcData is NULL or zDataSize is 0.

Juno_CrcCcitt32Update()

uint32_t Juno_CrcCcitt32Update	(	uint32_t	iCrc,
		const void *	pcData,
		size_t	zDataSize
	)

Update CCITT32 CRC (32-bit) with new data.

Parameters

iCrc	Running CRC value (use JUNO_CCITT32_CRC_INIT initially).
pcData	Pointer to data buffer (can be NULL when zDataSize is 0).
zDataSize	Size of data buffer in bytes.

Returns

Updated CRC value; returns 0 when pcData is NULL or zDataSize is 0.

Juno_CrcCcittUpdate()

uint16_t Juno_CrcCcittUpdate	(	uint16_t	iCrc,
		const void *	pcData,
		size_t	zDataSize
	)

Update CCITT CRC (16-bit) with new data.

Parameters

iCrc	Running CRC value (use JUNO_CCITT_CRC_INIT initially).
pcData	Pointer to data buffer (can be NULL when zDataSize is 0).
zDataSize	Size of data buffer in bytes.

Returns

Updated CRC value; returns 0 when pcData is NULL or zDataSize is 0.

Juno_CrcKermitUpdate()

uint16_t Juno_CrcKermitUpdate	(	uint16_t	iCrc,
		const void *	pcData,
		size_t	zDataSize
	)

Update Kermit CRC with new data.

Parameters

iCrc	Running CRC value (use JUNO_KERMIT_CRC_INIT initially).
pcData	Pointer to data buffer (can be NULL when zDataSize is 0).
zDataSize	Size of data buffer in bytes.

Returns

Updated CRC value; returns 0 when pcData is NULL or zDataSize is 0.

Juno_CrcZipUpdate()

uint32_t Juno_CrcZipUpdate	(	uint32_t	iCrc,
		const void *	pcData,
		size_t	zDataSize
	)

Update ZIP CRC (CRC-32) with new data.

Applies a final XOR (0xFFFFFFFF) to the computed value before returning when data is processed. If streaming across multiple chunks, undo the XOR on the returned value before using it as the next iCrc. When pcData is NULL or zDataSize is 0, the function returns 0 (no XOR is applied in that case).

Parameters

iCrc	Running CRC value (use JUNO_ZIP_CRC_INIT initially).
pcData	Pointer to data buffer (can be NULL when zDataSize is 0).
zDataSize	Size of data buffer in bytes.

Returns

Updated CRC-32 value; returns 0 when pcData is NULL or zDataSize is 0.