speed up the em4x05 cmds by only getting 6k...

[proxmark3-svn] / common / lfdemod.c

diff --git a/common/lfdemod.c b/common/lfdemod.c
index c66f3e04cf0dd835ab748de21baedd0a00612ed8..fbed6a9a8431fa913a4d56cba47b19297571ff4e 100644 (file)
--- a/common/lfdemod.c
+++ b/common/lfdemod.c
@@ -170,6 +170,23 @@ uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_
        return 0;
 }
 
+// search for given preamble in given BitStream and return success=1 or fail=0 and startIndex (where it was found)
+// does not look for a repeating preamble
+// em4x05/4x69 only sends preamble once, so look for it once in the first pLen bits
+// leave it generic so it could be reused later...
+bool onePreambleSearch(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 false;
+       for (size_t idx = 0; idx < size - pLen; idx++) {
+               if (memcmp(BitStream+idx, preamble, pLen) == 0) {
+                       if (g_debugMode) prnt("DEBUG: preamble found at %u", idx);
+                       *startIdx = idx;
+                       return true;
+               }
+       }
+       return false;
+}
+
 //by marshmellow
 //takes 1s and 0s and searches for EM410x format - output EM ID
 uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)