- //get high and low peak
- int peak, low;
- if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return 0;
-
- //PrintAndLog("DEBUG: peak: %d, low: %d",peak,low);
- size_t ii;
- uint8_t clkCnt;
- uint8_t tol = 0;
- uint16_t peakcnt=0;
- uint16_t peaksdet[]={0,0,0,0,0,0,0,0};
- uint16_t maxPeak=0;
- //test for large clipped waves
- for (i=0; i<loopCnt; i++){
- if (dest[i] >= peak || dest[i] <= low){
- peakcnt++;
- } else {
- if (peakcnt>0 && maxPeak < peakcnt){
- maxPeak = peakcnt;
- }
- peakcnt=0;
- }
- }
- peakcnt=0;
- //test each valid clock from smallest to greatest to see which lines up
- for(clkCnt=0; clkCnt < 8; ++clkCnt){
- //ignore clocks smaller than largest peak
- if (clk[clkCnt]<maxPeak) continue;
-
- //try lining up the peaks by moving starting point (try first 256)
- for (ii=0; ii< loopCnt; ++ii){
- if ((dest[ii] >= peak) || (dest[ii] <= low)){
- peakcnt=0;
- // now that we have the first one lined up test rest of wave array
- for (i=0; i < ((int)((size-ii-tol)/clk[clkCnt])-1); ++i){
- if (dest[ii+(i*clk[clkCnt])]>=peak || dest[ii+(i*clk[clkCnt])]<=low){
- peakcnt++;
- }
- }
- if(peakcnt>peaksdet[clkCnt]) {
- peaksdet[clkCnt]=peakcnt;
- }
- }
- }
- }
- int iii=7;
- uint8_t best=0;
- for (iii=7; iii > 0; iii--){
- if (peaksdet[iii] > peaksdet[best]){
- best = iii;
- }
- //PrintAndLog("DEBUG: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[iii],peaksdet[iii],bestErr[iii],clk[best]);
- }
- return clk[best];
-}
-
-// by marshmellow
-// convert psk1 demod to psk2 demod
-// only transition waves are 1s
-void psk1TOpsk2(uint8_t *BitStream, size_t size)
-{
- size_t i=1;
- uint8_t lastBit=BitStream[0];
- for (; i<size; i++){
- if (BitStream[i]==77){
- //ignore errors
- } else if (lastBit!=BitStream[i]){
- lastBit=BitStream[i];
- BitStream[i]=1;
- } else {
- BitStream[i]=0;
- }
- }
- return;
-}
-
-// by marshmellow
-// convert psk2 demod to psk1 demod
-// from only transition waves are 1s to phase shifts change bit
-void psk2TOpsk1(uint8_t *BitStream, size_t size)
-{
- uint8_t phase=0;
- for (size_t i=0; i<size; i++){
- if (BitStream[i]==1){
- phase ^=1;
- }
- BitStream[i]=phase;
- }
- return;
-}
-
-// redesigned by marshmellow adjusted from existing decode functions
-// indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
-int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert)
-{
- //26 bit 40134 format (don't know other formats)
- int i;
- int long_wait=29;//29 leading zeros in format
- int start;
- int first = 0;
- int first2 = 0;
- int bitCnt = 0;
- int ii;
- // Finding the start of a UID
- for (start = 0; start <= *size - 250; start++) {
- first = bitStream[start];
- for (i = start; i < start + long_wait; i++) {
- if (bitStream[i] != first) {
- break;
- }
- }
- if (i == (start + long_wait)) {
- break;
- }
- }
- if (start == *size - 250 + 1) {
- // did not find start sequence
- return -1;
- }
- // Inverting signal if needed
- if (first == 1) {
- for (i = start; i < *size; i++) {
- bitStream[i] = !bitStream[i];
- }
- *invert = 1;
- }else *invert=0;
-
- int iii;
- //found start once now test length by finding next one
- for (ii=start+29; ii <= *size - 250; ii++) {
- first2 = bitStream[ii];
- for (iii = ii; iii < ii + long_wait; iii++) {
- if (bitStream[iii] != first2) {
- break;
- }
- }
- if (iii == (ii + long_wait)) {
- break;
- }
- }
- if (ii== *size - 250 + 1){
- // did not find second start sequence
- return -2;
- }
- bitCnt=ii-start;
-
- // Dumping UID
- i = start;
- for (ii = 0; ii < bitCnt; ii++) {
- bitStream[ii] = bitStream[i++];
- }
- *size=bitCnt;
- return 1;
-}
-
-// by marshmellow - demodulate NRZ wave (both similar enough)
-// peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
-// there probably is a much simpler way to do this....
-int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert, int maxErr)
-{
- if (justNoise(dest, *size)) return -1;
- *clk = DetectNRZClock(dest, *size, *clk);
- if (*clk==0) return -2;
- size_t i, gLen = 4096;
- if (gLen>*size) gLen = *size;
- int high, low;
- if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low
- int lastBit = 0; //set first clock check
- size_t iii = 0, bitnum = 0; //bitnum counter
- uint16_t errCnt = 0, MaxBits = 1000;
- size_t bestErrCnt = maxErr+1;
- size_t bestPeakCnt = 0, bestPeakStart = 0;
- uint8_t bestFirstPeakHigh=0, firstPeakHigh=0, curBit=0, bitHigh=0, errBitHigh=0;
- uint8_t tol = 1; //clock tolerance adjust - waves will be accepted as within the clock if they fall + or - this value + clock from last valid wave
- uint16_t peakCnt=0;
- uint8_t ignoreWindow=4;
- uint8_t ignoreCnt=ignoreWindow; //in case of noise near peak
- //loop to find first wave that works - align to clock
- for (iii=0; iii < gLen; ++iii){
- if ((dest[iii]>=high) || (dest[iii]<=low)){
- if (dest[iii]>=high) firstPeakHigh=1;
- else firstPeakHigh=0;
- lastBit=iii-*clk;
- peakCnt=0;
- errCnt=0;
- //loop through to see if this start location works
- for (i = iii; i < *size; ++i) {
- // if we are at a clock bit
- if ((i >= lastBit + *clk - tol) && (i <= lastBit + *clk + tol)) {
- //test high/low
- if (dest[i] >= high || dest[i] <= low) {
- bitHigh = 1;
- peakCnt++;
- errBitHigh = 0;
- ignoreCnt = ignoreWindow;
- lastBit += *clk;
- } else if (i == lastBit + *clk + tol) {
- lastBit += *clk;
- }
- //else if no bars found
- } else if (dest[i] < high && dest[i] > low){
- if (ignoreCnt==0){
- bitHigh=0;
- if (errBitHigh==1) errCnt++;
- errBitHigh=0;
- } else {
- ignoreCnt--;
- }
- } else if ((dest[i]>=high || dest[i]<=low) && (bitHigh==0)) {
- //error bar found no clock...
- errBitHigh=1;
- }
- if (((i-iii) / *clk)>=MaxBits) break;
- }
- //we got more than 64 good bits and not all errors
- if (((i-iii) / *clk) > 64 && (errCnt <= (maxErr))) {
- //possible good read
- if (!errCnt || peakCnt > bestPeakCnt){
- bestFirstPeakHigh=firstPeakHigh;
- bestErrCnt = errCnt;
- bestPeakCnt = peakCnt;
- bestPeakStart = iii;
- if (!errCnt) break; //great read - finish
- }
- }
- }
- }
- //PrintAndLog("DEBUG: bestErrCnt: %d, maxErr: %d, bestStart: %d, bestPeakCnt: %d, bestPeakStart: %d",bestErrCnt,maxErr,bestStart,bestPeakCnt,bestPeakStart);
- if (bestErrCnt > maxErr) return bestErrCnt;
-
- //best run is good enough set to best run and set overwrite BinStream
- lastBit = bestPeakStart - *clk;
- memset(dest, bestFirstPeakHigh^1, bestPeakStart / *clk);
- bitnum += (bestPeakStart / *clk);
- for (i = bestPeakStart; i < *size; ++i) {
- // if expecting a clock bit
- if ((i >= lastBit + *clk - tol) && (i <= lastBit + *clk + tol)) {
- // test high/low
- if (dest[i] >= high || dest[i] <= low) {
- peakCnt++;
- bitHigh = 1;
- errBitHigh = 0;
- ignoreCnt = ignoreWindow;
- curBit = *invert;
- if (dest[i] >= high) curBit ^= 1;
- dest[bitnum++] = curBit;
- lastBit += *clk;
- //else no bars found in clock area
- } else if (i == lastBit + *clk + tol) {
- dest[bitnum++] = curBit;
- lastBit += *clk;
- }
- //else if no bars found
- } else if (dest[i] < high && dest[i] > low){
- if (ignoreCnt == 0){
- bitHigh = 0;
- if (errBitHigh == 1){
- dest[bitnum++] = 77;
- errCnt++;
- }
- errBitHigh=0;
- } else {
- ignoreCnt--;
- }
- } else if ((dest[i] >= high || dest[i] <= low) && (bitHigh == 0)) {
- //error bar found no clock...
- errBitHigh=1;
- }
- if (bitnum >= MaxBits) break;
- }
- *size = bitnum;
- return bestErrCnt;
-}
-
-//by marshmellow
-//detects the bit clock for FSK given the high and low Field Clocks
-uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow)
-{
- uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
- uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
- uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
- uint8_t rfLensFnd = 0;
- uint8_t lastFCcnt = 0;
- uint16_t fcCounter = 0;
- uint16_t rfCounter = 0;
- uint8_t firstBitFnd = 0;
- size_t i;
- if (size == 0) return 0;
-
- uint8_t fcTol = (uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
- rfLensFnd=0;
- fcCounter=0;
- rfCounter=0;
- firstBitFnd=0;
- //PrintAndLog("DEBUG: fcTol: %d",fcTol);
- // prime i to first up transition
- for (i = 1; i < size-1; i++)
- if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
- break;
-
- for (; i < size-1; i++){
- fcCounter++;
- rfCounter++;