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Add generic CRC calculation code

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henryk@ploetzli.ch 2009-11-25 20:41:41 +00:00
commit 68d9d60a4d
3 changed files with 90 additions and 1 deletions
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41
common/crc.c Normal file
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/*
* crc.c
*
* Generic CRC calculation code.
*
*/
#include "crc.h"
void crc_init(crc_t *crc, int order, uint32_t polynom, uint32_t initial_value, uint32_t final_xor)
{
crc->order = order;
crc->polynom = polynom;
crc->initial_value = initial_value;
crc->final_xor = final_xor;
crc->mask = (1L<<order)-1;
crc_clear(crc);
}
void crc_update(crc_t *crc, uint32_t data, int data_width)
{
int i;
for(i=0; i<data_width; i++) {
int oldstate = crc->state;
crc->state = crc->state >> 1;
if( (oldstate^data) & 1 ) {
crc->state ^= crc->polynom;
}
data >>= 1;
}
}
void crc_clear(crc_t *crc)
{
crc->state = crc->initial_value & crc->mask;
}
uint32_t crc_finish(crc_t *crc)
{
return ( crc->state ^ crc->final_xor ) & crc->mask;
}