FIX: coverity scan 133850, again. Why on earth did the 7 come from. I removed it.

[proxmark3-svn] / common / lfdemod.c

diff --git a/common/lfdemod.c b/common/lfdemod.c
index 8b31f1a4c10a751cd447d2667aa89f7a57a7e22e..7e31f53dcccb66b04e3c5d04b809cf5f20308477 100644 (file)
--- a/common/lfdemod.c
+++ b/common/lfdemod.c
@@ -723,6 +723,39 @@ int FDXBdemodBI(uint8_t *dest, size_t *size)
        return (int)startIdx;
 }
 
+// ASK/Diphase fc/64 (inverted Biphase)
+// Note: this i s not a demod, this is only a detection
+// the parameter *dest needs to be demoded before call
+int JablotronDemod(uint8_t *dest, size_t *size){
+       //make sure buffer has enough data
+       if (*size < 64) return -1;
+
+       size_t startIdx = 0;
+       // 0xFFFF preamble, 64bits
+       uint8_t preamble[] = {
+                       1,1,1,1,
+                   1,1,1,1,
+                               1,1,1,1,
+                               1,1,1,1,
+                               0
+               };
+
+       uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
+       if (errChk == 0) return -4; //preamble not found
+       if (*size != 64) return -3;
+       
+       uint8_t checkchksum = 0;
+       for (int i=16; i < 56; i += 8) {
+               checkchksum += bytebits_to_byte(dest+startIdx+i,8);
+       }
+       checkchksum ^= 0x3A;
+
+       uint8_t crc = bytebits_to_byte(dest+startIdx+56, 8);
+       
+       if ( checkchksum != crc ) return -5;    
+       return (int)startIdx;
+}
+
 // by marshmellow
 // FSK Demod then try to locate an AWID ID
 int AWIDdemodFSK(uint8_t *dest, size_t *size)