em4x05 getting better

[proxmark3-svn] / common / lfdemod.c

diff --git a/common/lfdemod.c b/common/lfdemod.c
index 8324c440f4c19f918159215ff6dc94b397596f80..2ee66a521596d15aa3adc2044495a6eb680d306e 100644 (file)
--- a/common/lfdemod.c
+++ b/common/lfdemod.c
@@ -62,7 +62,7 @@ uint8_t parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType)
        for (uint8_t i = 0; i < bitLen; i++){
                ans ^= ((bits >> i) & 1);
        }
-       //PrintAndLog("DEBUG: ans: %d, ptype: %d",ans,pType);
+       if (g_debugMode) prnt("DEBUG: ans: %d, ptype: %d, bits: %08X",ans,pType,bits);
        return (ans == pType);
 }
 
@@ -73,11 +73,13 @@ size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t p
 {
        uint32_t parityWd = 0;
        size_t j = 0, bitCnt = 0;
-       for (int word = 0; word < (bLen); word+=pLen){
-               for (int bit=0; bit < pLen; bit++){
+       for (int word = 0; word < (bLen); word+=pLen) {
+               for (int bit=0; bit < pLen; bit++) {
                        parityWd = (parityWd << 1) | BitStream[startIdx+word+bit];
                        BitStream[j++] = (BitStream[startIdx+word+bit]);
                }
+               if (word+pLen >= bLen) break;
+
                j--; // overwrite parity with next data
                // if parity fails then return 0
                switch (pType) {
@@ -148,6 +150,9 @@ uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits)
 //search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length
 uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx)
 {
+       // Sanity check.  If preamble length is bigger than bitstream length.
+       if ( *size <= pLen ) return 0;
+
        uint8_t foundCnt=0;
        for (int idx=0; idx < *size - pLen; idx++){
                if (memcmp(BitStream+idx, preamble, pLen) == 0){
@@ -1372,10 +1377,10 @@ uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj)
        uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
        uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
        uint8_t fcLensFnd = 0;
-       uint8_t lastFCcnt=0;
+       uint8_t lastFCcnt = 0;
        uint8_t fcCounter = 0;
        size_t i;
-       if (size == 0) return 0;
+       if (size < 180) return 0;
 
        // prime i to first up transition
        for (i = 160; i < size-20; i++)