+
+int manchester_decode( int * data, const size_t len, uint8_t * dataout, size_t dataoutlen){
+
+ int bitlength = 0;
+ int i, clock, high, low, startindex;
+ low = startindex = 0;
+ high = 1;
+ uint8_t * bitStream = (uint8_t* ) malloc(sizeof(uint8_t) * dataoutlen);
+ memset(bitStream, 0x00, dataoutlen);
+
+ /* Detect high and lows */
+ for (i = 0; i < len; i++) {
+ if (data[i] > high)
+ high = data[i];
+ else if (data[i] < low)
+ low = data[i];
+ }
+
+ /* get clock */
+ clock = GetT55x7Clock( data, len, high );
+ startindex = DetectFirstTransition(data, len, high);
+
+ //PrintAndLog(" Clock : %d", clock);
+
+ if (high != 1)
+ bitlength = ManchesterConvertFrom255(data, len, bitStream, dataoutlen, high, low, clock, startindex);
+ else
+ bitlength= ManchesterConvertFrom1(data, len, bitStream, dataoutlen, clock, startindex);
+
+ memcpy(dataout, bitStream, bitlength);
+ free(bitStream);
+ return bitlength;
+}
+
+ int GetT55x7Clock( const int * data, const size_t len, int peak ){
+
+ int i,lastpeak,clock;
+ clock = 0xFFFF;
+ lastpeak = 0;
+
+ /* Detect peak if we don't have one */
+ if (!peak) {
+ for (i = 0; i < len; ++i) {
+ if (data[i] > peak) {
+ peak = data[i];
+ }
+ }
+ }
+
+ for (i = 1; i < len; ++i) {
+ /* if this is the beginning of a peak */
+ if ( data[i-1] != data[i] && data[i] == peak) {
+ /* find lowest difference between peaks */
+ if (lastpeak && i - lastpeak < clock)
+ clock = i - lastpeak;
+ lastpeak = i;
+ }
+ }
+
+ // When detected clock is 31 or 33 then then return
+ int clockmod = clock%8;
+ if ( clockmod == 0) return clock;
+
+ if ( clockmod == 7 ) clock += 1;
+ else if ( clockmod == 1 ) clock -= 1;
+
+ return clock;
+ }
+
+ int DetectFirstTransition(const int * data, const size_t len, int threshold){
+
+ int i =0;
+ /* now look for the first threshold */
+ for (; i < len; ++i) {
+ if (data[i] == threshold) {
+ break;
+ }
+ }
+ return i;
+ }
+
+ int ManchesterConvertFrom255(const int * data, const size_t len, uint8_t * dataout, int dataoutlen, int high, int low, int clock, int startIndex){
+
+ int i, j, z, hithigh, hitlow, bitIndex, startType;
+ i = 0;
+ bitIndex = 0;
+
+ int isDamp = 0;
+ int damplimit = (int)((high / 2) * 0.3);
+ int dampHi = (high/2)+damplimit;
+ int dampLow = (high/2)-damplimit;
+ int firstST = 0;
+
+ // i = clock frame of data
+ for (; i < (int)(len/clock); i++)
+ {
+ hithigh = 0;
+ hitlow = 0;
+ startType = -1;
+ z = startIndex + (i*clock);
+ isDamp = 0;
+
+ /* Find out if we hit both high and low peaks */
+ for (j = 0; j < clock; j++)
+ {
+ if (data[z+j] == high){
+ hithigh = 1;
+ if ( startType == -1)
+ startType = 1;
+ }
+
+ if (data[z+j] == low ){
+ hitlow = 1;
+ if ( startType == -1)
+ startType = 0;
+ }
+
+ if (hithigh && hitlow)
+ break;
+ }
+
+ // No high value found, are we in a dampening field?
+ if ( !hithigh ) {
+ //PrintAndLog(" # Entering damp test at index : %d (%d)", z+j, j);
+ for (j = 0; j < clock; j++) {
+ if (
+ (data[z+j] <= dampHi && data[z+j] >= dampLow)
+ ){
+ isDamp++;
+ }
+ }
+ }
+
+ /* Manchester Switching..
+ 0: High -> Low
+ 1: Low -> High
+ */
+ if (startType == 0)
+ dataout[bitIndex++] = 1;
+ else if (startType == 1)
+ dataout[bitIndex++] = 0;
+ else
+ dataout[bitIndex++] = 2;
+
+ if ( isDamp > clock/2 ) {
+ firstST++;
+ }
+
+ if ( firstST == 4)
+ break;
+ if ( bitIndex >= dataoutlen-1 )
+ break;
+ }
+ return bitIndex;
+ }
+
+ int ManchesterConvertFrom1(const int * data, const size_t len, uint8_t * dataout,int dataoutlen, int clock, int startIndex){
+
+ PrintAndLog(" Path B");
+
+ int i,j, bitindex, lc, tolerance, warnings;
+ warnings = 0;
+ int upperlimit = len*2/clock+8;
+ i = startIndex;
+ j = 0;
+ tolerance = clock/4;
+ uint8_t decodedArr[len];
+
+ /* Detect duration between 2 successive transitions */
+ for (bitindex = 1; i < len; i++) {
+
+ if (data[i-1] != data[i]) {
+ lc = i - startIndex;
+ startIndex = i;
+
+ // Error check: if bitindex becomes too large, we do not
+ // have a Manchester encoded bitstream or the clock is really wrong!
+ if (bitindex > upperlimit ) {
+ PrintAndLog("Error: the clock you gave is probably wrong, aborting.");
+ return 0;
+ }
+ // Then switch depending on lc length:
+ // Tolerance is 1/4 of clock rate (arbitrary)
+ if (abs((lc-clock)/2) < tolerance) {
+ // Short pulse : either "1" or "0"
+ decodedArr[bitindex++] = data[i-1];
+ } else if (abs(lc-clock) < tolerance) {
+ // Long pulse: either "11" or "00"
+ decodedArr[bitindex++] = data[i-1];
+ decodedArr[bitindex++] = data[i-1];
+ } else {
+ ++warnings;
+ PrintAndLog("Warning: Manchester decode error for pulse width detection.");
+ if (warnings > 10) {
+ PrintAndLog("Error: too many detection errors, aborting.");
+ return 0;
+ }
+ }
+ }
+ }
+
+ /*
+ * We have a decodedArr of "01" ("1") or "10" ("0")
+ * parse it into final decoded dataout
+ */
+ for (i = 0; i < bitindex; i += 2) {
+
+ if ((decodedArr[i] == 0) && (decodedArr[i+1] == 1)) {
+ dataout[j++] = 1;
+ } else if ((decodedArr[i] == 1) && (decodedArr[i+1] == 0)) {
+ dataout[j++] = 0;
+ } else {
+ i++;
+ warnings++;
+ PrintAndLog("Unsynchronized, resync...");
+ PrintAndLog("(too many of those messages mean the stream is not Manchester encoded)");
+
+ if (warnings > 10) {
+ PrintAndLog("Error: too many decode errors, aborting.");
+ return 0;
+ }
+ }
+ }
+
+ PrintAndLog("%s", sprint_hex(dataout, j));
+ return j;
+ }
+
+ void ManchesterDiffDecodedString(const uint8_t* bitstream, size_t len, uint8_t invert){
+ /*
+ * We have a bitstream of "01" ("1") or "10" ("0")
+ * parse it into final decoded bitstream
+ */
+ int i, j, warnings;
+ uint8_t decodedArr[(len/2)+1];
+
+ j = warnings = 0;
+
+ uint8_t lastbit = 0;
+
+ for (i = 0; i < len; i += 2) {
+
+ uint8_t first = bitstream[i];
+ uint8_t second = bitstream[i+1];
+
+ if ( first == second ) {
+ ++i;
+ ++warnings;
+ if (warnings > 10) {
+ PrintAndLog("Error: too many decode errors, aborting.");
+ return;
+ }
+ }
+ else if ( lastbit != first ) {
+ decodedArr[j++] = 0 ^ invert;
+ }
+ else {
+ decodedArr[j++] = 1 ^ invert;
+ }
+ lastbit = second;
+ }
+
+ PrintAndLog("%s", sprint_hex(decodedArr, j));
+}
+
+void PrintPaddedManchester( uint8_t* bitStream, size_t len, size_t blocksize){
+
+ PrintAndLog(" Manchester decoded : %d bits", len);
+
+ uint8_t mod = len % blocksize;
+ uint8_t div = len / blocksize;
+ int i;
+
+ // Now output the bitstream to the scrollback by line of 16 bits
+ for (i = 0; i < div*blocksize; i+=blocksize) {
+ PrintAndLog(" %s", sprint_bin(bitStream+i,blocksize) );
+ }
+
+ if ( mod > 0 )
+ PrintAndLog(" %s", sprint_bin(bitStream+i, mod) );
+}
+
+/* Sliding DFT
+ Smooths out
+*/
+void iceFsk2(int * data, const size_t len){
+
+ int i, j;
+ int * output = (int* ) malloc(sizeof(int) * len);
+ memset(output, 0x00, len);
+
+ // for (i=0; i<len-5; ++i){
+ // for ( j=1; j <=5; ++j) {
+ // output[i] += data[i*j];
+ // }
+ // output[i] /= 5;
+ // }
+ int rest = 127;
+ int tmp =0;
+ for (i=0; i<len; ++i){
+ if ( data[i] < 127)
+ output[i] = 0;
+ else {
+ tmp = (100 * (data[i]-rest)) / rest;
+ output[i] = (tmp > 60)? 100:0;
+ }
+ }
+
+ for (j=0; j<len; ++j)
+ data[j] = output[j];
+
+ free(output);
+}
+
+void iceFsk3(int * data, const size_t len){
+
+ int i,j;
+
+ int * output = (int* ) malloc(sizeof(int) * len);
+ memset(output, 0x00, len);
+ float fc = 0.1125f; // center frequency
+ size_t adjustedLen = len;
+
+ // create very simple low-pass filter to remove images (2nd-order Butterworth)
+ float complex iir_buf[3] = {0,0,0};
+ float b[3] = {0.003621681514929, 0.007243363029857, 0.003621681514929};
+ float a[3] = {1.000000000000000, -1.822694925196308, 0.837181651256023};
+
+ float sample = 0; // input sample read from file
+ float complex x_prime = 1.0f; // save sample for estimating frequency
+ float complex x;
+
+ for (i=0; i<adjustedLen; ++i) {
+
+ sample = data[i]+128;
+
+ // remove DC offset and mix to complex baseband
+ x = (sample - 127.5f) * cexpf( _Complex_I * 2 * M_PI * fc * i );
+
+ // apply low-pass filter, removing spectral image (IIR using direct-form II)
+ iir_buf[2] = iir_buf[1];
+ iir_buf[1] = iir_buf[0];
+ iir_buf[0] = x - a[1]*iir_buf[1] - a[2]*iir_buf[2];
+ x = b[0]*iir_buf[0] +
+ b[1]*iir_buf[1] +
+ b[2]*iir_buf[2];
+
+ // compute instantaneous frequency by looking at phase difference
+ // between adjacent samples
+ float freq = cargf(x*conjf(x_prime));
+ x_prime = x; // retain this sample for next iteration
+
+ output[i] =(freq > 0)? 10 : -10;
+ }
+
+ // show data
+ for (j=0; j<adjustedLen; ++j)
+ data[j] = output[j];
+
+ CmdLtrim("30");
+ adjustedLen -= 30;
+
+ // zero crossings.
+ for (j=0; j<adjustedLen; ++j){
+ if ( data[j] == 10) break;
+ }
+ int startOne =j;
+
+ for (;j<adjustedLen; ++j){
+ if ( data[j] == -10 ) break;
+ }
+ int stopOne = j-1;
+
+ int fieldlen = stopOne-startOne;
+
+ fieldlen = (fieldlen == 39 || fieldlen == 41)? 40 : fieldlen;
+ fieldlen = (fieldlen == 59 || fieldlen == 51)? 50 : fieldlen;
+ if ( fieldlen != 40 && fieldlen != 50){
+ printf("Detected field Length: %d \n", fieldlen);
+ printf("Can only handle 40 or 50. Aborting...\n");
+ return;
+ }
+
+ // FSK sequence start == 000111
+ int startPos = 0;
+ for (i =0; i<adjustedLen; ++i){
+ int dec = 0;
+ for ( j = 0; j < 6*fieldlen; ++j){
+ dec += data[i + j];
+ }
+ if (dec == 0) {
+ startPos = i;
+ break;
+ }
+ }
+
+ printf("000111 position: %d \n", startPos);
+
+ startPos += 6*fieldlen+5;
+
+ int bit =0;
+ printf("BINARY\n");
+ printf("R/40 : ");
+ for (i =startPos ; i < adjustedLen; i += 40){
+ bit = data[i]>0 ? 1:0;
+ printf("%d", bit );
+ }
+ printf("\n");
+
+ printf("R/50 : ");
+ for (i =startPos ; i < adjustedLen; i += 50){
+ bit = data[i]>0 ? 1:0;
+ printf("%d", bit ); }
+ printf("\n");
+
+ free(output);
+}
+
+float complex cexpf (float complex Z)
+{
+ float complex Res;
+ double rho = exp (__real__ Z);
+ __real__ Res = rho * cosf(__imag__ Z);
+ __imag__ Res = rho * sinf(__imag__ Z);
+ return Res;
+}
projects / proxmark3-svn / blobdiff