}
-uint8_t manchester_decode(const uint8_t * data, const size_t len, uint8_t * dataout){
+int manchester_decode(const int * data, const size_t len, uint8_t * dataout){
- size_t bytelength = len;
-
- uint8_t bitStream[bytelength];
- memset(bitStream, 0x00, bytelength);
-
- int clock,high, low, bit, hithigh, hitlow, first, bit2idx, lastpeak;
- int i,invert, lastval;
- int bitidx = 0;
- int lc = 0;
- int warnings = 0;
+ int bitlength = 0;
+ int i, clock, high, low, startindex;
+ low = startindex = 0;
high = 1;
- low = bit = bit2idx = lastpeak = invert = lastval = hithigh = hitlow = first = 0;
- clock = 0xFFFF;
+ uint8_t bitStream[len];
+ memset(bitStream, 0x00, len);
+
/* Detect high and lows */
- for (i = 0; i < bytelength; i++) {
+ for (i = 0; i < len; i++) {
if (data[i] > high)
high = data[i];
else if (data[i] < low)
}
/* get clock */
- int j=0;
- for (i = 1; i < bytelength; i++) {
+ clock = GetT55x7Clock( data, len, high );
+ startindex = DetectFirstTransition(data, len, high, low);
+
+ PrintAndLog(" Clock : %d", clock);
+ PrintAndLog(" startindex : %d", startindex);
+
+ if (high != 1)
+ bitlength = ManchesterConvertFrom255(data, len, bitStream, high, low, clock, startindex);
+ else
+ bitlength= ManchesterConvertFrom1(data, len, bitStream, clock, startindex);
+
+ if ( bitlength > 0 ){
+ PrintPaddedManchester(bitStream, bitlength, clock);
+ }
+
+ 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 */
- j = i-1;
- if ( data[j] != data[i] &&
- data[i] == high)
- {
+ if ( data[i-1] != data[i] && data[i] == peak) {
/* find lowest difference between peaks */
if (lastpeak && i - lastpeak < clock)
clock = i - lastpeak;
lastpeak = i;
}
}
-
- int tolerance = clock/4;
- PrintAndLog(" Detected clock: %d",clock);
-
- /* Detect first transition */
- /* Lo-Hi (arbitrary) */
- /* skip to the first high */
- for (i= 0; i < bytelength; i++)
+ //return clock;
+ //defaults clock to precise values.
+ switch(clock){
+ case 8:
+ case 16:
+ case 32:
+ case 40:
+ case 50:
+ case 64:
+ case 100:
+ case 128:
+ return clock;
+ break;
+ default: break;
+ }
+ return 32;
+ }
+
+ int DetectFirstTransition(const int * data, const size_t len, int high, int low){
+
+ int i, retval;
+ retval = 0;
+ /*
+ Detect first transition Lo-Hi (arbitrary)
+ skip to the first high
+ */
+ for (i = 0; i < len; ++i)
if (data[i] == high)
break;
/* now look for the first low */
- for (; i < bytelength; i++) {
+ for (; i < len; ++i) {
if (data[i] == low) {
- lastval = i;
+ retval = i;
break;
}
}
-
- /* If we're not working with 1/0s, demod based off clock */
- if (high != 1)
+ return retval;
+ }
+
+ int ManchesterConvertFrom255(const int * data, const size_t len, uint8_t * dataout, int high, int low, int clock, int startIndex){
+
+ int i, j, hithigh, hitlow, first, bit, bitIndex;
+ i = startIndex;
+ bitIndex = 0;
+
+ /*
+ * We assume the 1st bit is zero, it may not be
+ * the case: this routine (I think) has an init problem.
+ * Ed.
+ */
+ bit = 0;
+
+ for (; i < (int)(len / clock); i++)
{
- bit = 0; /* We assume the 1st bit is zero, it may not be
- * the case: this routine (I think) has an init problem.
- * Ed.
- */
- for (; i < (int)(bytelength / clock); i++)
- {
hithigh = 0;
hitlow = 0;
first = 1;
if (hithigh && hitlow)
break;
- }
+ }
- /* If we didn't hit both high and low peaks, we had a bit transition */
- if (!hithigh || !hitlow)
+ /* If we didn't hit both high and low peaks, we had a bit transition */
+ if (!hithigh || !hitlow)
bit ^= 1;
- bitStream[bit2idx++] = bit ^ invert;
- }
+ dataout[bitIndex++] = bit;
}
- /* standard 1/0 bitstream */
- else {
- /* Then detect duration between 2 successive transitions */
- for (bitidx = 1; i < bytelength; i++) {
-
- if (data[i-1] != data[i]) {
- lc = i-lastval;
- lastval = i;
-
- // Error check: if bitidx becomes too large, we do not
- // have a Manchester encoded bitstream or the clock is really
- // wrong!
- if (bitidx > (bytelength*2/clock+8) ) {
- 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"
- bitStream[bitidx++] = data[i-1];
- } else if (abs(lc-clock) < tolerance) {
- // Long pulse: either "11" or "00"
- bitStream[bitidx++] = data[i-1];
- bitStream[bitidx++] = data[i-1];
- } else {
- // Error
- warnings++;
- PrintAndLog("Warning: Manchester decode error for pulse width detection.");
- if (warnings > 10) {
- PrintAndLog("Error: too many detection errors, aborting.");
- return 0;
- }
+ return bitIndex;
+ }
+
+ int ManchesterConvertFrom1(const int * data, const size_t len, uint8_t * dataout, int clock, int startIndex){
+
+ 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];
+
+ /* Then 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;
}
}
}
}
- // At this stage, we now have a bitstream of "01" ("1") or "10" ("0"), parse it into final decoded bitstream
- // Actually, we overwrite BitStream with the new decoded bitstream, we just need to be careful
- // to stop output at the final bitidx2 value, not bitidx
- for (i = 0; i < bitidx; i += 2) {
- if ((bitStream[i] == 0) && (bitStream[i+1] == 1)) {
- bitStream[bit2idx++] = 1 ^ invert;
- }
- else if ((bitStream[i] == 1) && (bitStream[i+1] == 0)) {
- bitStream[bit2idx++] = 0 ^ invert;
- }
- else {
- // We cannot end up in this state, this means we are unsynchronized,
- // move up 1 bit:
+
+ /*
+ * 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...");
- if (warnings > 10) {
+ 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];
- // PrintAndLog(" Manchester decoded bitstream : %d bits", (bit2idx-16));
- // uint8_t mod = (bit2idx-16) % blocksize;
- // uint8_t div = (bit2idx-16) / blocksize;
-
- // // 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) );
- // }
+ j = warnings = 0;
- if ( bit2idx > 0 )
- memcpy(dataout, bitStream, bit2idx);
+ uint8_t lastbit = 0;
- free(bitStream);
- return bit2idx;
-}
+ 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 bitstream : %d bits", len);
projects / proxmark3-svn / blobdiff