1 files changed, 127 insertions, 0 deletions
diff --git a/src/lib/utils/mem_ops.h b/src/lib/utils/mem_ops.h
index f9e39fa31..6ea7bdafe 100644
--- a/src/lib/utils/mem_ops.h
+++ b/src/lib/utils/mem_ops.h
@@ -10,6 +10,7 @@
 
 #include <botan/types.h>
 #include <cstring>
+#include <vector>
 
 namespace Botan {
 
@@ -70,6 +71,132 @@ template<typename T> inline bool same_mem(const T* p1, const T* p2, size_t n)
    return difference == 0;
    }
 
+/**
+* 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
+*/
+template<typename T>
+void xor_buf(T out[], const T in[], size_t length)
+   {
+   while(length >= 8)
+      {
+      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];
+
+      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
+*/
+template<typename T> void xor_buf(T out[],
+                                  const T in[],
+                                  const T in2[],
+                                  size_t length)
+   {
+   while(length >= 8)
+      {
+      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];
+
+      in += 8; in2 += 8; out += 8; length -= 8;
+      }
+
+   for(size_t i = 0; i != length; ++i)
+      out[i] = in[i] ^ in2[i];
+   }
+
+#if BOTAN_TARGET_UNALIGNED_MEMORY_ACCESS_OK
+
+template<>
+inline void xor_buf<byte>(byte out[], const byte in[], size_t length)
+   {
+   while(length >= 8)
+      {
+      *reinterpret_cast<u64bit*>(out) ^= *reinterpret_cast<const u64bit*>(in);
+      out += 8; in += 8; length -= 8;
+      }
+
+   for(size_t i = 0; i != length; ++i)
+      out[i] ^= in[i];
+   }
+
+template<>
+inline void xor_buf<byte>(byte out[],
+                          const byte in[],
+                          const byte in2[],
+                          size_t length)
+   {
+   while(length >= 8)
+      {
+      *reinterpret_cast<u64bit*>(out) =
+         *reinterpret_cast<const u64bit*>(in) ^
+         *reinterpret_cast<const u64bit*>(in2);
+
+      in += 8; in2 += 8; out += 8; length -= 8;
+      }
+
+   for(size_t i = 0; i != length; ++i)
+      out[i] = in[i] ^ in2[i];
+   }
+
+#endif
+
+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.data(), in.data(), n);
+   }
+
+template<typename Alloc>
+void xor_buf(std::vector<byte, Alloc>& out,
+             const byte* in,
+             size_t n)
+   {
+   xor_buf(out.data(), 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.data(), in, in2.data(), 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.data(), in.data(), in.size());
+   return out;
+   }
+
 }
 
 #endif