Refactor parity functions

[proxmark3-svn] / common / parity.h

diff --git a/common/parity.h b/common/parity.h
new file mode 100644 (file)
index 0000000..615fdee
--- /dev/null
+++ b/common/parity.h
@@ -0,0 +1,53 @@
+//-----------------------------------------------------------------------------
+// This code is licensed to you under the terms of the GNU GPL, version 2 or,
+// at your option, any later version. See the LICENSE.txt file for the text of
+// the license.
+//-----------------------------------------------------------------------------
+// Parity functions
+//-----------------------------------------------------------------------------
+
+// all functions defined in header file by purpose. Allows compiler optimizations. 
+
+#ifndef __PARITY_H
+#define __PARITY_H
+
+#include <stdint.h>
+#include <stdbool.h>
+
+extern const uint8_t OddByteParity[256];
+
+
+static inline bool oddparity8(const uint8_t x) {
+       return OddByteParity[x];
+}
+
+
+static inline bool evenparity8(const uint8_t x) {
+       return !OddByteParity[x];
+}
+
+
+static inline bool evenparity32(uint32_t x) 
+{
+#if !defined __GNUC__
+       x ^= x >> 16;
+       x ^= x >> 8;
+       return evenparity8(x);
+#else
+       return __builtin_parity(x);
+#endif
+}
+
+
+static inline bool oddparity32(uint32_t x) 
+{
+#if !defined __GNUC__
+       x ^= x >> 16;
+       x ^= x >> 8;
+       return oddparity8(x);
+#else
+       return !__builtin_parity(x);
+#endif
+}
+
+#endif /* __PARITY_H */