- }
- 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++)
- {
- hithigh = 0;
- hitlow = 0;
- first = 1;
-
- /* Find out if we hit both high and low peaks */
- for (j = 0; j < clock; j++)
- {
- if (data[(i * clock) + j] == high)
- hithigh = 1;
- else if (data[(i * clock) + j] == low)
- hitlow = 1;
-
- /* it doesn't count if it's the first part of our read
- because it's really just trailing from the last sequence */
- if (first && (hithigh || hitlow))
- hithigh = hitlow = 0;
- else
- first = 0;
-
- if (hithigh && hitlow)
- break;
- }
-
- /* If we didn't hit both high and low peaks, we had a bit transition */
- if (!hithigh || !hitlow)
- bit ^= 1;
-
- dataout[bitIndex++] = bit;
- }
- 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;
- }
- }
- }