+
+// RotateLeft - Ultralight, Desfire, works on byte level
+// 00-01-02 >> 01-02-00
+void rol(uint8_t *data, const size_t len){
+ uint8_t first = data[0];
+ for (size_t i = 0; i < len-1; i++) {
+ data[i] = data[i+1];
+ }
+ data[len-1] = first;
+}
+
+// Swap bit order on a uint32_t value. Can be limited by nrbits just use say 8bits reversal
+// And clears the rest of the bits.
+uint32_t SwapBits(uint32_t value, int nrbits) {
+ uint32_t newvalue = 0;
+ for(int i = 0; i < nrbits; i++) {
+ newvalue ^= ((value >> i) & 1) << (nrbits - 1 - i);
+ }
+ return newvalue;
+}
+/*
+ ref http://www.csm.ornl.gov/~dunigan/crc.html
+ Returns the value v with the bottom b [0,32] bits reflected.
+ Example: reflect(0x3e23L,3) == 0x3e26
+*/
+uint32_t reflect(uint32_t v, int b) {
+ uint32_t t = v;
+ for ( int i = 0; i < b; ++i) {
+ if (t & 1)
+ v |= BITMASK((b-1)-i);
+ else
+ v &= ~BITMASK((b-1)-i);
+ t>>=1;
+ }
+ return v;
+}
+
+uint64_t HornerScheme(uint64_t num, uint64_t divider, uint64_t factor) {
+ uint64_t remainder=0, quotient=0, result=0;
+ remainder = num % divider;
+ quotient = num / divider;
+ if(!(quotient == 0 && remainder == 0))
+ result += HornerScheme(quotient, divider, factor) * factor + remainder;
+ return result;
+}
\ No newline at end of file