//-----------------------------------------------------------------------------
// This code is licensed to you under the terms of the GNU GPL, version 2 or,
// at your option, any later version. See the LICENSE.txt file for the text of
// the license.
//-----------------------------------------------------------------------------
// Wiegand functions
//-----------------------------------------------------------------------------
#include "wiegand.h"
/*
* @brief getParity
* @param bits pointer to the source bitstream of binary values 0|1
* @param len how long shall parity be calculated
* @param type use the defined values EVEN|ODD
* @return parity bit required to match type
*/
uint8_t getParity( uint8_t *bits, uint8_t len, uint8_t type ) {
uint8_t x = 0;
for(; len > 0; --len)
x += bits[len - 1];
return (x & 1 ) ^ type;
}
// by marshmellow
/* pass bits to be tested in bits, length bits passed in bitLen, and parity type EVEN|ODD in type
* @brief checkParity
* @param bits pointer to the source bitstream of binary values 0|1
* @param len number of bits to be checked
* @param type use the defined values EVEN|ODD
* @return 1 if passed
*/
uint8_t checkParity(uint32_t bits, uint8_t len, uint8_t type);
// by marshmellow
// takes a array of binary values, start position, length of bits per parity (includes parity bit),
// Parity Type (1 for odd; 0 for even; 2 for Always 1's; 3 for Always 0's), and binary Length (length to run)
size_t removeParity(uint8_t *bitstream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen) {
uint32_t parityWd = 0;
size_t j = 0, bitcount = 0;
for (int word = 0; word < (bLen); word += pLen){
for (int bit = 0; bit < pLen; ++bit){
parityWd = (parityWd << 1) | bitstream[startIdx+word+bit];
bitstream[j++] = (bitstream[startIdx + word + bit]);
}
j--; // overwrite parity with next data
// if parity fails then return 0
switch (pType) {
case 3: if (bitstream[j] == 1) return 0; break; //should be 0 spacer bit
case 2: if (bitstream[j] == 0) return 0; break; //should be 1 spacer bit
default: //test parity
if (parityTest(parityWd, pLen, pType) == 0) return 0; break;
}
bitcount += ( pLen - 1 );
parityWd = 0;
}
// if we got here then all the parities passed
//return ID start index and size
return bitcount;
}
// by marshmellow
// takes a array of binary values, length of bits per parity (includes parity bit),
// Parity Type (1 for odd; 0 for even; 2 Always 1's; 3 Always 0's), and binary Length (length to run)
// Make sure *dest is long enough to store original sourceLen + #_of_parities_to_be_added
/*
* @brief addParity
* @param bits pointer to the source bitstream of binary values
* @param dest pointer to the destination where parities together with bits are added.
* @param sourceLen number of
* @param pLen length bits to be checked
* @param pType EVEN|ODD|2 (always 1's)|3 (always 0's)
* @return
*/
size_t addParity(uint8_t *bits, uint8_t *dest, uint8_t sourceLen, uint8_t pLen, uint8_t pType)
{
uint32_t parityWd = 0;
size_t j = 0, bitCnt = 0;
for (int word = 0; word < sourceLen; word += pLen-1) {
for (int bit = 0; bit < pLen-1; ++bit){
parityWd = (parityWd << 1) | bits[word+bit];
dest[j++] = (bits[word+bit]);
}
// if parity fails then return 0
switch (pType) {
case 3: dest[j++] = 0; break; // marker bit which should be a 0
case 2: dest[j++] = 1; break; // marker bit which should be a 1
default:
dest[j++] = parityTest(parityWd, pLen-1, pType) ^ 1;
break;
}
bitCnt += pLen;
parityWd = 0;
}
// if we got here then all the parities passed
//return ID start index and size
return bitCnt;
}
// by marshmellow
/*
* add HID parity to binary array: EVEN prefix for 1st half of ID, ODD suffix for 2nd half
* @brief wiegand_add_parity
* @param source pointer to source of binary data
* @param dest pointer to the destination where wiegandparity has been appended
* @param len number of bits which wiegand parity shall be calculated over. This number is without parities, so a wiegand 26 has 24 bits of data
*/
void wiegand_add_parity(uint8_t *source, uint8_t *dest, uint8_t len) {
// Copy to destination, shifted one step to make room for EVEN parity
memcpy(dest+1, source, length);
// half length, Even and Odd is calculated to the middle.
uint8_t len_h2 = length >> 1;
// add EVEN parity at the beginning
*(dest) = GetParity(source, EVEN, len_h2);
dest += length + 1;
// add ODD parity at the very end
*(dest) = GetParity(source + len_h2, ODD, len_h2);
}
//uint32_t bytebits_to_byte(uint8_t* src, size_t numbits);
#define MAX_BITS_TXX55 6*4*8
#define MAX_BYTES_TXX55 6*4
/*
* @brief num_to_wiegand_bytes
* @param oem Sometimes call FF Fixfield, SiteCode. Used in a few formats
* @param fc Facility code
* @param cn Card number
* @param dest pointer to the destination where wiegand bytes will be stored
* @param formatlen
*/
void num_to_wiegand_bytes(uint64_t oem, uint64_t fc, uint64_t cn, uint8_t *dest, uint8_t formatlen){
uint8_t data[MAX_BITS_TXX55] = {0};
memset(data, 0, sizeof(data));
num_to_wiegand_bits(oem, fc, cn, data, formatlen);
// loop
// (formatlen / 32 ) + 1
// (formatlen >> 5) + 1
for (int i = 0; i < formatlen ; ++i){
uint32_t value = bytebits_to_byte( data + (i * 32), 32);
num_to_bytes(value, 32, dest + (i*4) );
}
}
/*
* @brief num_to_wiegand_bits
* @param oem Sometimes call FF Fixfield, SiteCode. Used in a few formats
* @param fc Facility code
* @param cn Card number
* @param dest pointer to the destination where wiegand bits will be stored
* @param formatlen
*/
void num_to_wiegand_bits(uint64_t oem, uint64_t fc, uint64_t cn, uint8_t *dest, uint8_t formatlen){
uint8_t bits[MAX_BITS_TXX55] = {0};
memset(bits, 0, sizeof(bits));
uint8_t *temp = bits;
uint64_t value = 0;
switch ( formatlen ){
case 26 : // 26bit HID H10301
fc &= 0xFF; // 8bits
cn &= 0xFFFF; // 16bits
value = fc << 16 | cn;
num_to_bytebits(value, 24, temp);
wiegand_add_parity(temp, dest, 24);
break;
case 261: // 26bit Indala
fc &= 0xFFF; // 12bits
cn &= 0xFFF; // 12bits
value = fc << 12 | cn;
num_to_bytebits(value, 24, temp);
wiegand_add_parity(temp, dest, 24);
break;
case 34 : // 34bits HID
fc &= 0xFFFF; // 16bits
cn &= 0xFFFF; // 16bits
value = fc << 16 | cn;
num_to_bytebits(value, 32, temp);
wiegand_add_parity(temp, dest, 32);
break;
case 35 : // 35bits HID
fc &= 0xFFF; // 12bits
cn &= 0xFFFFFF; // 20bits
value = fc << 20 | cn;
num_to_bytebits(value, 32, temp);
wiegand_add_parity(temp, dest, 32);
break;
case 37 : // H10304
fc &= 0xFFFF; // 16bits
cn &= 0x7FFFF; // 19bits
value = fc << 19 | cn;
num_to_bytebits(value, 35, temp);
wiegand_add_parity(temp, dest, 35);
break;
case 39 : // 39bit KERI System Pyramid
fc &= 0x1FFFF; // 17bits
cn &= 0xFFFFFFFF; // 20bits
value = fc << 20 | cn;
num_to_bytebits(value, 37, temp);
wiegand_add_parity(temp, dest, 37);
break;
case 44 : // 44bit KERI system Pyramid
oem &= 0xFF; // 8bits
fc &= 0xFFF; // 12bits
cn &= 0xFFFFFFFF; // 21bits
value = oem << 20 | fc << 12 | cn;
num_to_bytebits(value, 42, temp);
wiegand_add_parity(temp, dest, 42);
break;
case 50 : // AWID 50 RBH
fc &= 0xFFFF; // 16bits
cn &= 0xFFFFFFFF // 32bits
value = fc << 32 | cn;
num_to_bytebits(value, 48, temp);
wiegand_add_parity(temp, dest, 48); // verify!
break;
default:
break;
}
}