1 files changed, 113 insertions, 0 deletions
diff --git a/lib/utils/xor_buf.h b/lib/utils/xor_buf.h
new file mode 100644
index 000000000..5773a619c
--- /dev/null
+++ b/lib/utils/xor_buf.h
@@ -0,0 +1,113 @@
+/*
+* XOR operations
+* (C) 1999-2008 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#ifndef BOTAN_XOR_BUF_H__
+#define BOTAN_XOR_BUF_H__
+
+#include <botan/types.h>
+#include <vector>
+
+namespace Botan {
+
+/**
+* XOR arrays. Postcondition out[i] = in[i] ^ out[i] forall i = 0...length
+* @param out the input/output buffer
+* @param in the read-only input buffer
+* @param length the length of the buffers
+*/
+inline void xor_buf(byte out[], const byte in[], size_t length)
+   {
+   while(length >= 8)
+      {
+#if BOTAN_TARGET_UNALIGNED_MEMORY_ACCESS_OK
+      *reinterpret_cast<u64bit*>(out) ^= *reinterpret_cast<const u64bit*>(in);
+#else
+      out[0] ^= in[0]; out[1] ^= in[1];
+      out[2] ^= in[2]; out[3] ^= in[3];
+      out[4] ^= in[4]; out[5] ^= in[5];
+      out[6] ^= in[6]; out[7] ^= in[7];
+#endif
+
+      out += 8; in += 8; length -= 8;
+      }
+
+   for(size_t i = 0; i != length; ++i)
+      out[i] ^= in[i];
+   }
+
+/**
+* XOR arrays. Postcondition out[i] = in[i] ^ in2[i] forall i = 0...length
+* @param out the output buffer
+* @param in the first input buffer
+* @param in2 the second output buffer
+* @param length the length of the three buffers
+*/
+inline void xor_buf(byte out[],
+                    const byte in[],
+                    const byte in2[],
+                    size_t length)
+   {
+   while(length >= 8)
+      {
+#if BOTAN_TARGET_UNALIGNED_MEMORY_ACCESS_OK
+      *reinterpret_cast<u64bit*>(out) =
+         *reinterpret_cast<const u64bit*>(in) ^
+         *reinterpret_cast<const u64bit*>(in2);
+#else
+      out[0] = in[0] ^ in2[0]; out[1] = in[1] ^ in2[1];
+      out[2] = in[2] ^ in2[2]; out[3] = in[3] ^ in2[3];
+      out[4] = in[4] ^ in2[4]; out[5] = in[5] ^ in2[5];
+      out[6] = in[6] ^ in2[6]; out[7] = in[7] ^ in2[7];
+#endif
+
+      in += 8; in2 += 8; out += 8; length -= 8;
+      }
+
+   for(size_t i = 0; i != length; ++i)
+      out[i] = in[i] ^ in2[i];
+   }
+
+template<typename Alloc, typename Alloc2>
+void xor_buf(std::vector<byte, Alloc>& out,
+             const std::vector<byte, Alloc2>& in,
+             size_t n)
+   {
+   xor_buf(&out[0], &in[0], n);
+   }
+
+template<typename Alloc>
+void xor_buf(std::vector<byte, Alloc>& out,
+             const byte* in,
+             size_t n)
+   {
+   xor_buf(&out[0], in, n);
+   }
+
+template<typename Alloc, typename Alloc2>
+void xor_buf(std::vector<byte, Alloc>& out,
+             const byte* in,
+             const std::vector<byte, Alloc2>& in2,
+             size_t n)
+   {
+   xor_buf(&out[0], &in[0], &in2[0], n);
+   }
+
+template<typename T, typename Alloc, typename Alloc2>
+std::vector<T, Alloc>&
+operator^=(std::vector<T, Alloc>& out,
+           const std::vector<T, Alloc2>& in)
+   {
+   if(out.size() < in.size())
+      out.resize(in.size());
+
+   xor_buf(&out[0], &in[0], in.size());
+   return out;
+   }
+
+}
+
+#endif