Fix viking demod bug - clean my indala demod code

[proxmark3-svn] / common / lfdemod.c

diff --git a/common/lfdemod.c b/common/lfdemod.c
index c8a2c69af82291e8486bd81cbadfb6dab1895fb7..32feab6a6589934fd7cb291b883337915e7a027d 100644 (file)
--- a/common/lfdemod.c
+++ b/common/lfdemod.c
@@ -602,7 +602,6 @@ int IOdemodFSK(uint8_t *dest, size_t size)
 // by marshmellow
 // find viking preamble 0xF200 in already demoded data
 int VikingDemod_AM(uint8_t *dest, size_t *size) {
-       if (justNoise(dest, *size)) return -1;
        //make sure buffer has data
        if (*size < 64*2) return -2;
 
@@ -614,7 +613,7 @@ int VikingDemod_AM(uint8_t *dest, size_t *size) {
            ^ bytebits_to_byte(dest+startIdx+24,8) ^ bytebits_to_byte(dest+startIdx+32,8) ^ bytebits_to_byte(dest+startIdx+40,8) 
            ^ bytebits_to_byte(dest+startIdx+48,8) ^ bytebits_to_byte(dest+startIdx+56,8);
        if ( checkCalc != 0xA8 ) return -5;
-       if (*size != 64) return -5;
+       if (*size != 64) return -6;
        //return start position
        return (int) startIdx;
 }
@@ -1074,63 +1073,20 @@ void psk2TOpsk1(uint8_t *BitStream, size_t size)
 int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert)
 {
        //26 bit 40134 format  (don't know other formats)
-       int i;
-       int long_wait=29;//29 leading zeros in format
-       int start;
-       int first = 0;
-       int first2 = 0;
-       int bitCnt = 0;
-       int ii;
-       // Finding the start of a UID
-       for (start = 0; start <= *size - 250; start++) {
-               first = bitStream[start];
-               for (i = start; i < start + long_wait; i++) {
-                       if (bitStream[i] != first) {
-                               break;
-                       }
-               }
-               if (i == (start + long_wait)) {
-                       break;
-               }
-       }
-       if (start == *size - 250 + 1) {
-               // did not find start sequence
-               return -1;
-       }
-       // Inverting signal if needed
-       if (first == 1) {
-               for (i = start; i < *size; i++) {
-                       bitStream[i] = !bitStream[i];
-               }
-               *invert = 1;
-       }else *invert=0;
-
-       int iii;
-       //found start once now test length by finding next one
-       for (ii=start+29; ii <= *size - 250; ii++) {
-               first2 = bitStream[ii];
-               for (iii = ii; iii < ii + long_wait; iii++) {
-                       if (bitStream[iii] != first2) {
-                               break;
-                       }
-               }
-               if (iii == (ii + long_wait)) {
-                       break;
-               }
-       }
-       if (ii== *size - 250 + 1){
-               // did not find second start sequence
-               return -2;
-       }
-       bitCnt=ii-start;
+       uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
+       uint8_t preamble_i[] = {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0};
+       size_t startidx = 0; 
+       if (!preambleSearch(bitStream, preamble, sizeof(preamble), size, &startidx)){
+               // if didn't find preamble try again inverting
+               if (!preambleSearch(bitStream, preamble_i, sizeof(preamble_i), size, &startidx)) return -1;
+               *invert ^= 1;
+       } 
+       if (*size != 64 && *size != 224) return -2;
+       if (*invert==1)
+               for (size_t i = startidx; i < *size; i++)
+                       bitStream[i] ^= 1;
 
-       // Dumping UID
-       i = start;
-       for (ii = 0; ii < bitCnt; ii++) {
-               bitStream[ii] = bitStream[i++];
-       }
-       *size=bitCnt;
-       return 1;
+       return (int) startidx;
 }
 
 // by marshmellow - demodulate NRZ wave (both similar enough)