X-Git-Url: http://cvs.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/5215a874429bf41ec24c83d6d5f631233faf3d76..a47ded5b54e19b779bc4260466dcd093c2695d63:/common/lfdemod.c

diff --git a/common/lfdemod.c b/common/lfdemod.c
index ca126df3..58b843e2 100644
--- a/common/lfdemod.c
+++ b/common/lfdemod.c
@@ -203,10 +203,11 @@ size_t findModStart(uint8_t dest[], size_t size, uint8_t threshold_value, uint8_
 //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)
 {
 	// sanity check
-	if (BitStream[1] > 1) return 0; 
+	if (*size < 64) return -3;	
+	if (BitStream[1] > 1) return -1; 
 	
 	uint8_t fmtlen;
 	*startIdx = 0;
@@ -214,11 +215,13 @@ uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_
 	// 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 == 110) ? 22 : 10;
+	fmtlen = (*size == 128) ? 22 : 10;
 
 	//skip last 4bit parity row for simplicity
 	*size = removeParity(BitStream, *startIdx + sizeof(preamble), 5, 0, fmtlen * 5);  
@@ -236,14 +239,14 @@ uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_
 		*lo = ((uint64_t)(bytebits_to_byte(BitStream + 24, 32)) << 32) | (bytebits_to_byte(BitStream + 24 + 32, 32));
 		break;
 	    } 
-	    default: return 0;
-	
+	    default: return -4;	
 	}
 	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;
@@ -387,25 +390,30 @@ int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr
 //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){
@@ -413,9 +421,9 @@ int manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert){
 		} else {
 			BitStream[bitnum++] = 7;
 		}
-		if (bitnum>MaxBits) break;
+		if (bitnum > MaxBits) break;
 	}
-	*size=bitnum;
+	*size = bitnum;
 	return bestErr;
 }
 
@@ -1675,9 +1683,14 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
 	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};
@@ -1832,7 +1845,7 @@ bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
 	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)
@@ -1840,6 +1853,15 @@ bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
 			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) {