//-----------------------------------------------------------------------------
// Generic CRC calculation code.
//-----------------------------------------------------------------------------
-
+// the Check value below in the comments is CRC of the string '123456789'
+//
#include "crc.h"
-void crc_init(crc_t *crc, int order, uint32_t polynom, uint32_t initial_value, uint32_t final_xor)
-{
+void crc_init_ref(crc_t *crc, int order, uint32_t polynom, uint32_t initial_value, uint32_t final_xor, bool refin, bool refout) {
+ crc_init(crc, order, polynom, initial_value, final_xor);
+ crc->refin = refin;
+ crc->refout = refout;
+ crc_clear(crc);
+}
+
+void crc_init(crc_t *crc, int order, uint32_t polynom, uint32_t initial_value, uint32_t final_xor) {
crc->order = order;
+ crc->topbit = BITMASK( order-1 );
crc->polynom = polynom;
crc->initial_value = initial_value;
crc->final_xor = final_xor;
crc->mask = (1L<<order)-1;
+ crc->refin = FALSE;
+ crc->refout = FALSE;
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;
+ if (crc->refin)
+ crc->state = reflect(crc->state, crc->order);
+}
+
+void crc_update(crc_t *crc, uint32_t indata, int data_width){
+
+ //reflected
+ if (crc->refin) indata = reflect(indata, data_width);
+
+ // Bring the next byte into the remainder.
+ crc->state ^= indata << (crc->order - data_width);
+
+ for( uint8_t bit = data_width; bit > 0; --bit) {
+ // Try to divide the current data bit.
+ if (crc->state & crc->topbit)
+ crc->state = (crc->state << 1) ^ crc->polynom;
+ else
+ crc->state = (crc->state << 1);
}
}
-void crc_clear(crc_t *crc)
-{
- crc->state = crc->initial_value & crc->mask;
+uint32_t crc_finish(crc_t *crc) {
+ uint32_t val = crc->state;
+ if (crc->refout) val = reflect(val, crc->order);
+ return ( val ^ crc->final_xor ) & crc->mask;
+}
+
+/*
+static void print_crc(crc_t *crc) {
+ printf(" Order %d\n Poly %x\n Init %x\n Final %x\n Mask %x\n topbit %x\n RefIn %s\n RefOut %s\n State %x\n",
+ crc->order,
+ crc->polynom,
+ crc->initial_value,
+ crc->final_xor,
+ crc->mask,
+ crc->topbit,
+ (crc->refin) ? "TRUE":"FALSE",
+ (crc->refout) ? "TRUE":"FALSE",
+ crc->state
+ );
}
+*/
-uint32_t crc_finish(crc_t *crc)
-{
- return ( crc->state ^ crc->final_xor ) & crc->mask;
+// width=8 poly=0x31 init=0x00 refin=true refout=true xorout=0x00 check=0xA1 name="CRC-8/MAXIM"
+uint32_t CRC8Maxim(uint8_t *buff, size_t size) {
+ crc_t crc;
+ crc_init_ref(&crc, 8, 0x31, 0, 0, TRUE, TRUE);
+ for ( int i=0; i < size; ++i)
+ crc_update(&crc, buff[i], 8);
+ return crc_finish(&crc);
}
+
+// width=4 poly=0xC, reversed poly=0x7 init=0x5 refin=true refout=true xorout=0x0000 check= name="CRC-4/LEGIC"
+// width=8 poly=0x63, reversed poly=0x8D init=0x55 refin=true refout=true xorout=0x0000 check=0xC6 name="CRC-8/LEGIC"
+// the CRC needs to be reversed before returned.
+uint32_t CRC8Legic(uint8_t *buff, size_t size) {
+ crc_t crc;
+ crc_init_ref(&crc, 8, 0x63, 0x55, 0, TRUE, TRUE);
+ for ( int i = 0; i < size; ++i)
+ crc_update(&crc, buff[i], 8);
+ return reflect(crc_finish(&crc), 8);
+}
+
+// This CRC-16 is used in Legic Advant systems.
+// width=8 poly=0xB400, reversed poly=0x init=depends refin=true refout=true xorout=0x0000 check= name="CRC-16/LEGIC"
+uint32_t CRC16Legic(uint8_t *buff, size_t size, uint8_t uidcrc) {
+
+ #define CRC16_POLY_LEGIC 0xB400
+ uint16_t initial = reflect(uidcrc, 8);
+ //uint16_t initial = uidcrc;
+ initial |= initial << 8;
+ crc_t crc;
+ crc_init_ref(&crc, 16, CRC16_POLY_LEGIC, initial, 0, TRUE, TRUE);
+ for ( int i=0; i < size; ++i)
+ crc_update(&crc, buff[i], 8);
+ return reflect(crc_finish(&crc), 16);
+}
+
+//w=16 poly=0x3d65 init=0x0000 refin=true refout=true xorout=0xffff check=0xea82 name="CRC-16/DNP"
+uint32_t CRC16_DNP(uint8_t *buff, size_t size) {
+ crc_t crc;
+ crc_init_ref(&crc, 16, 0x3d65, 0, 0xffff, TRUE, TRUE);
+ for ( int i=0; i < size; ++i)
+ crc_update(&crc, buff[i], 8);
+
+ return BSWAP_16(crc_finish(&crc));
+}
+
+//width=16 poly=0x1021 init=0x1d0f refin=false refout=false xorout=0x0000 check=0xe5cc name="CRC-16/AUG-CCITT"
+uint32_t CRC16_CCITT(uint8_t *buff, size_t size) {
+ crc_t crc;
+ crc_init(&crc, 16, 0x1021, 0x1d0f, 0);
+ for ( int i=0; i < size; ++i)
+ crc_update(&crc, buff[i], 8);
+ return crc_finish(&crc);
+}
+//width=16 poly=0x8408 init=0xffff refin=false refout=true xorout=0xffff check=0xF0B8 name="CRC-16/ISO/IEC 13239"
+uint32_t CRC16_Iso15693(uint8_t *buff, size_t size) {
+ crc_t crc;
+ crc_init_ref(&crc, 16, 0x8408, 0xFFFF, 0xFFFF, true, false);
+ for ( int i=0; i < size; ++i)
+ crc_update(&crc, buff[i], 8);
+ return reflect(crc_finish(&crc), 16);
+}
+//width=16 poly=0x8408 init=0xffff refin=true refout=true xorout=0x0BC3 check=0xF0B8 name="CRC-16/ICLASS"
+uint32_t CRC16_ICLASS(uint8_t *buff, size_t size) {
+
+ crc_t crc;
+ crc_init_ref(&crc, 16, 0x8408, 0xFFFF, 0x0BC3, false, false);
+ for ( int i=0; i < size; ++i)
+ crc_update(&crc, buff[i], 8);
+ return crc_finish(&crc);
+}
\ No newline at end of file
projects / proxmark3-svn / blobdiff