Split byte swap code and word rotation code off into bswap.h and rotate.h

1 files changed, 39 insertions, 0 deletions

diff --git a/include/bswap.h b/include/bswap.h
new file mode 100644
index 000000000..e38d3c6fa
--- /dev/null
+++ b/include/bswap.h
@@ -0,0 +1,39 @@
+/*************************************************
+* Byte Swapping Operations Header File           *
+* (C) 1999-2008 Jack Lloyd                       *
+*************************************************/
+
+#ifndef BOTAN_BSWAP_H__
+#define BOTAN_BSWAP_H__
+
+#include <botan/types.h>
+#include <botan/rotate.h>
+
+namespace Botan {
+
+/*************************************************
+* Byte Swapping Functions                        *
+*************************************************/
+inline u16bit reverse_bytes(u16bit input)
+   {
+   return rotate_left(input, 8);
+   }
+
+inline u32bit reverse_bytes(u32bit input)
+   {
+   input = ((input & 0xFF00FF00) >> 8) | ((input & 0x00FF00FF) << 8);
+   return rotate_left(input, 16);
+   }
+
+inline u64bit reverse_bytes(u64bit input)
+   {
+   u32bit hi = ((input >> 40) & 0x00FF00FF) | ((input >> 24) & 0xFF00FF00);
+   u32bit lo = ((input & 0xFF00FF00) >> 8) | ((input & 0x00FF00FF) << 8);
+   hi = (hi << 16) | (hi >> 16);
+   lo = (lo << 16) | (lo >> 16);
+   return (static_cast<u64bit>(lo) << 32) | hi;
+   }
+
+}
+
+#endif