(memxor3): New function, suggested by Adam Langley.

Rev: src/nettle/memxor.c:1.4
Rev: src/nettle/memxor.h:1.4

memxor.c

@@ -13,7 +13,8 @@
 
 #include "memxor.h"
 
-uint8_t *memxor(uint8_t *dst, const uint8_t *src, size_t n)
+uint8_t *
+memxor(uint8_t *dst, const uint8_t *src, size_t n)
 {
   size_t i;
   for (i = 0; i<n; i++)
@@ -21,3 +22,14 @@ uint8_t *memxor(uint8_t *dst, const uint8_t *src, size_t n)
 
   return dst;
 }
+
+uint8_t *
+memxor3(uint8_t *dst, const uint8_t *a, const uint8_t *b, size_t n)
+{
+  size_t i;
+  for (i = 0; i<n; i++)
+    dst[i] = a[i] ^ b[i];
+
+  return dst;
+}
+

memxor.h

@@ -9,5 +9,6 @@
 #include "nettle-types.h"
 
 uint8_t *memxor(uint8_t *dst, const uint8_t *src, size_t n);
+uint8_t *memxor3(uint8_t *dst, const uint8_t *a, const uint8_t *b, size_t n);
 
 #endif /* NETTLE_MEMXOR_H_INCLUDED */