parityWd = (parityWd << 1) | BitStream[startIdx+word+bit];
BitStream[j++] = (BitStream[startIdx+word+bit]);
}
- if (word+pLen >= bLen) break;
+ if (word+pLen > bLen) break;
j--; // overwrite parity with next data
// if parity fails then return 0
uint8_t foundCnt = 0;
for (int idx = 0; idx < *size - pLen; idx++){
if (memcmp(BitStream+idx, preamble, pLen) == 0){
- if (g_debugMode) prnt("DEBUG: preamble found at %u", idx);
+ if (g_debugMode) prnt("DEBUG: preamble found at %i", idx);
//first index found
foundCnt++;
if (foundCnt == 1){
//by marshmellow
//takes 1s and 0s and searches for EM410x format - output EM ID
// actually, no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future
-uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
+int Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
{
- //allow only 1s and 0s
- // only checking first bitvalue?!
- if (BitStream[1] > 1) return 0;
+ // sanity check
+ if (*size < 64) return -3;
+ if (BitStream[1] > 1) return -1;
- uint32_t i = 0, idx = 0, parityBits = 0;
- uint8_t fmtlen = 0;
+ uint8_t fmtlen;
*startIdx = 0;
// preamble 0111111111
// include 0 in front to help get start pos
uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};
- if (!preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx))
- return 0;
- if (*size < 64) return 0;
+ if (!preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx))
+ return -2;
+
+ //XL and normal size.
+ if (*size != 64 && *size != 128) return -3;
- fmtlen = (*size > 64) ? 22 : 10;
+ fmtlen = (*size == 128) ? 22 : 10;
- idx = *startIdx + sizeof(preamble);
+ //skip last 4bit parity row for simplicity
+ *size = removeParity(BitStream, *startIdx + sizeof(preamble), 5, 0, fmtlen * 5);
- //loop through 10 or 22 sets of 5 bits (50-10p = 40 bits or 88 bits)
- for (i=0; i < fmtlen; i++){
- parityBits = bytebits_to_byte(BitStream + (i*5) + idx, 5);
- //check even parity
- if (parityTest(parityBits, 5, 0) == 0) return 0;
- //set uint64 with ID from BitStream
- for (uint8_t j = 0; j < 4; j++){
- *hi = (*hi << 1) | (*lo >> 63);
- *lo = (*lo << 1) | (BitStream[(i*5) + j + idx]);
- }
+ switch (*size) {
+ case 40: {
+ // std em410x format
+ *hi = 0;
+ *lo = ((uint64_t)(bytebits_to_byte(BitStream, 8)) << 32) | (bytebits_to_byte(BitStream + 8, 32));
+ break;
+ }
+ case 88: {
+ // long em format
+ *hi = (bytebits_to_byte(BitStream, 24));
+ *lo = ((uint64_t)(bytebits_to_byte(BitStream + 24, 32)) << 32) | (bytebits_to_byte(BitStream + 24 + 32, 32));
+ break;
+ }
+ default: return -4;
}
- //skip last 5 bit parity test for simplicity.
- // *size = 64 | 128;
return 1;
}
//by marshmellow
//demodulates strong heavily clipped samples
+//RETURN: num of errors. if 0, is ok.
int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low)
{
size_t bitCnt=0, smplCnt=0, errCnt=0;
//by marshmellow
//take 10 and 01 and manchester decode
//run through 2 times and take least errCnt
-int manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert){
+int manrawdecode(uint8_t *BitStream, size_t *size, uint8_t invert){
+
+ // sanity check
+ if (*size < 16) return -1;
+
int errCnt = 0, bestErr = 1000;
uint16_t bitnum = 0, MaxBits = 512, bestRun = 0;
size_t i, k;
- if (*size < 16) return -1;
+
//find correct start position [alignment]
- for (k=0; k < 2; ++k){
- for (i=k; i<*size-3; i += 2)
+ for (k = 0; k < 2; ++k){
+ for (i = k; i < *size-3; i += 2) {
if (BitStream[i] == BitStream[i+1])
errCnt++;
-
+ }
if (bestErr > errCnt){
bestErr = errCnt;
bestRun = k;
}
- errCnt=0;
+ errCnt = 0;
}
+
//decode
- for (i=bestRun; i < *size-3; i += 2){
+ for (i = bestRun; i < *size-3; i += 2){
if (BitStream[i] == 1 && (BitStream[i+1] == 0)){
BitStream[bitnum++] = invert;
} else if ((BitStream[i] == 0) && BitStream[i+1] == 1){
} else {
BitStream[bitnum++] = 7;
}
- if (bitnum>MaxBits) break;
+ if (bitnum > MaxBits) break;
}
- *size=bitnum;
+ *size = bitnum;
return bestErr;
}
return errCnt;
}
+bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
+ size_t ststart = 0, stend = 0;
+ return DetectST_ext(buffer, size, foundclock, &ststart, &stend);
+}
+
//by marshmellow
//attempt to identify a Sequence Terminator in ASK modulated raw wave
-bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
+bool DetectST_ext(uint8_t buffer[], size_t *size, int *foundclock, size_t *ststart, size_t *stend) {
size_t bufsize = *size;
//need to loop through all samples and identify our clock, look for the ST pattern
uint8_t fndClk[] = {8,16,32,40,50,64,128};
size_t newloc = 0;
i=0;
if (g_debugMode==2) prnt("DEBUG STT: Starting STT trim - start: %d, datalen: %d ",dataloc, datalen);
-
+ bool firstrun = true;
// warning - overwriting buffer given with raw wave data with ST removed...
while ( dataloc < bufsize-(clk/2) ) {
//compensate for long high at end of ST not being high due to signal loss... (and we cut out the start of wave high part)
for(i=0; i < clk/2-tol; ++i) {
buffer[dataloc+i] = high+5;
}
+ } //test for single sample outlier (high between two lows) in the case of very strong waves
+ if (buffer[dataloc] >= high && buffer[dataloc+2] <= low) {
+ buffer[dataloc] = buffer[dataloc+2];
+ buffer[dataloc+1] = buffer[dataloc+2];
+ }
+ if (firstrun) {
+ *stend = dataloc;
+ *ststart = dataloc-(clk*4);
+ firstrun=false;
}
for (i=0; i<datalen; ++i) {
if (i+newloc < bufsize) {
projects / proxmark3-svn / blobdiff