crc.c File Reference

#include "qcommon.h"

Go to the source code of this file.

Macros
#define	CRC_INIT_VALUE   0xffff
#define	CRC_XOR_VALUE   0x0000

Functions
void	CRC_Init (unsigned short *crcvalue)
void	CRC_ProcessByte (unsigned short *crcvalue, byte data)
unsigned short	CRC_Value (unsigned short crcvalue)
unsigned short	CRC_Block (byte *start, int count)

Variables
static unsigned short	crctable [256]

Macro Definition Documentation

CRC_INIT_VALUE

#define CRC_INIT_VALUE   0xffff

Definition at line 28 of file crc.c.

CRC_XOR_VALUE

#define CRC_XOR_VALUE   0x0000

Definition at line 29 of file crc.c.

Function Documentation

CRC_Block()

unsigned short CRC_Block	(	byte *	start,
		int	count
	)

Definition at line 82 of file crc.c.

{
    unsigned short  crc;
 
    CRC_Init (&crc);
    while (count--)
        crc = (crc << 8) ^ crctable[(crc >> 8) ^ *start++];
 
    return crc;
}

Referenced by COM_BlockSequenceCRCByte().

CRC_Init()

void CRC_Init

(

unsigned short *

crcvalue

)

Definition at line 67 of file crc.c.

{
    *crcvalue = CRC_INIT_VALUE;
}

Referenced by CRC_Block().

CRC_ProcessByte()

void CRC_ProcessByte	(	unsigned short *	crcvalue,
		byte	data
	)

Definition at line 72 of file crc.c.

{
    *crcvalue = (*crcvalue << 8) ^ crctable[(*crcvalue >> 8) ^ data];
}

CRC_Value()

unsigned short CRC_Value

(

unsigned short

crcvalue

)

Definition at line 77 of file crc.c.

{
    return crcvalue ^ CRC_XOR_VALUE;
}

Variable Documentation

crctable

unsigned short crctable[256]

static

Definition at line 31 of file crc.c.

Referenced by CRC_Block(), and CRC_ProcessByte().