Split memxor.c into memxor.c and memxor3.c.

1 files changed, 2 insertions, 215 deletions

diff --git a/memxor.c b/memxor.c
index 940da020..a252a13d 100644
--- a/memxor.c
+++ b/memxor.c
@@ -1,6 +1,6 @@
 /* memxor.c
 
-   Copyright (C) 2010 Niels Möller
+   Copyright (C) 2010, 2014 Niels Möller
 
    This file is part of GNU Nettle.
 
@@ -40,24 +40,7 @@
 #include <limits.h>
 
 #include "memxor.h"
-
-/* For uintptr_t */
-#include "nettle-types.h"
-
-#if defined(__x86_64__) || defined(__arch64__)
-/* Including on M$ windows, where unsigned long is only 32 bits */
-typedef uint64_t word_t;
-#else
-typedef unsigned long int word_t;
-#endif
-
-#define ALIGN_OFFSET(p) ((uintptr_t) (p) % sizeof(word_t))
-
-#ifndef WORDS_BIGENDIAN
-#define MERGE(w0, sh_1, w1, sh_2) (((w0) >> (sh_1)) | ((w1) << (sh_2)))
-#else
-#define MERGE(w0, sh_1, w1, sh_2) (((w0) << (sh_1)) | ((w1) >> (sh_2)))
-#endif
+#include "memxor-internal.h"
 
 #define WORD_T_THRESH 16
 
@@ -159,199 +142,3 @@ memxor(void *dst_in, const void *src_in, size_t n)
 
   return dst;
 }
-
-
-/* XOR word-aligned areas. n is the number of words, not bytes. */
-static void
-memxor3_common_alignment (word_t *dst,
-			  const word_t *a, const word_t *b, size_t n)
-{
-  /* FIXME: Require n > 0? */
-  if (n & 1)
-    {
-      n--;
-      dst[n] = a[n] ^ b[n];
-    }
-  while (n > 0)
-    {
-      n -= 2;
-      dst[n+1] = a[n+1] ^ b[n+1];
-      dst[n] = a[n] ^ b[n];
-    }
-}
-
-static void
-memxor3_different_alignment_b (word_t *dst,
-			       const word_t *a, const char *b, unsigned offset, size_t n)
-{
-  int shl, shr;
-  const word_t *b_word;
-
-  word_t s0, s1;
-
-  shl = CHAR_BIT * offset;
-  shr = CHAR_BIT * (sizeof(word_t) - offset);
-
-  b_word = (const word_t *) ((uintptr_t) b & -sizeof(word_t));
-
-  if (n & 1)
-    {
-      n--;
-      s1 = b_word[n];
-      s0 = b_word[n+1];
-      dst[n] = a[n] ^ MERGE (s1, shl, s0, shr);
-    }
-  else
-    s1 = b_word[n];
-  
-  while (n > 0)
-    {
-      n -= 2;
-      s0 = b_word[n+1]; 
-      dst[n+1] = a[n+1] ^ MERGE(s0, shl, s1, shr);
-      s1 = b_word[n];
-      dst[n] = a[n] ^ MERGE(s1, shl, s0, shr);
-    }
-}
-
-static void
-memxor3_different_alignment_ab (word_t *dst,
-				const char *a, const char *b,
-				unsigned offset, size_t n)
-{
-  int shl, shr;
-  const word_t *a_word;
-  const word_t *b_word;
-  
-  word_t s0, s1;
-
-  shl = CHAR_BIT * offset;
-  shr = CHAR_BIT * (sizeof(word_t) - offset);
-
-  a_word = (const word_t *) ((uintptr_t) a & -sizeof(word_t));
-  b_word = (const word_t *) ((uintptr_t) b & -sizeof(word_t));
-
-  if (n & 1)
-    {
-      n--;
-      s1 = a_word[n] ^ b_word[n];
-      s0 = a_word[n+1] ^ b_word[n+1];
-      dst[n] = MERGE (s1, shl, s0, shr);
-    }
-  else    
-    s1 = a_word[n] ^ b_word[n];
-  
-  while (n > 0)
-    {
-      n -= 2;
-      s0 = a_word[n+1] ^ b_word[n+1]; 
-      dst[n+1] = MERGE(s0, shl, s1, shr);
-      s1 = a_word[n] ^ b_word[n];
-      dst[n] = MERGE(s1, shl, s0, shr);
-    }
-}
-
-static void
-memxor3_different_alignment_all (word_t *dst,
-				 const char *a, const char *b,
-				 unsigned a_offset, unsigned b_offset,
-				 size_t n)
-{
-  int al, ar, bl, br;
-  const word_t *a_word;
-  const word_t *b_word;
-  
-  word_t a0, a1, b0, b1;
-
-  al = CHAR_BIT * a_offset;
-  ar = CHAR_BIT * (sizeof(word_t) - a_offset);
-  bl = CHAR_BIT * b_offset;
-  br = CHAR_BIT * (sizeof(word_t) - b_offset);
-
-  a_word = (const word_t *) ((uintptr_t) a & -sizeof(word_t));
-  b_word = (const word_t *) ((uintptr_t) b & -sizeof(word_t));
-
-  if (n & 1)
-    {
-      n--;
-      a1 = a_word[n]; a0 = a_word[n+1];
-      b1 = b_word[n]; b0 = b_word[n+1];
-      
-      dst[n] = MERGE (a1, al, a0, ar) ^ MERGE (b1, bl, b0, br);
-    }
-  else    
-    {
-      a1 = a_word[n];
-      b1 = b_word[n];
-    }
-  
-  while (n > 0)
-    {
-      n -= 2;
-      a0 = a_word[n+1]; b0 = b_word[n+1]; 
-      dst[n+1] = MERGE(a0, al, a1, ar) ^ MERGE(b0, bl, b1, br);
-      a1 = a_word[n]; b1 = b_word[n];
-      dst[n] = MERGE(a1, al, a0, ar) ^ MERGE(b1, bl, b0, br);
-    }
-}
-
-/* Current implementation processes data in descending order, to
-   support overlapping operation with one of the sources overlapping
-   the start of the destination area. This feature is used only
-   internally by cbc decrypt, and it is not advertised or documented
-   to nettle users. */
-void *
-memxor3(void *dst_in, const void *a_in, const void *b_in, size_t n)
-{
-  char *dst = dst_in;
-  const char *a = a_in;
-  const char *b = b_in;
-
-  if (n >= WORD_T_THRESH)
-    {
-      unsigned i;
-      unsigned a_offset;
-      unsigned b_offset;
-      size_t nwords;
-
-      for (i = ALIGN_OFFSET(dst + n); i > 0; i--)
-	{
-	  n--;
-	  dst[n] = a[n] ^ b[n];
-	}
-
-      a_offset = ALIGN_OFFSET(a + n);
-      b_offset = ALIGN_OFFSET(b + n);
-
-      nwords = n / sizeof (word_t);
-      n %= sizeof (word_t);
-
-      if (a_offset == b_offset)
-	{
-	  if (!a_offset)
-	    memxor3_common_alignment((word_t *) (dst + n),
-				     (const word_t *) (a + n),
-				     (const word_t *) (b + n), nwords);
-	  else
-	    memxor3_different_alignment_ab((word_t *) (dst + n),
-					   a + n, b + n, a_offset,
-					   nwords);
-	}
-      else if (!a_offset)
-	memxor3_different_alignment_b((word_t *) (dst + n),
-				      (const word_t *) (a + n), b + n,
-				      b_offset, nwords);
-      else if (!b_offset)
-	memxor3_different_alignment_b((word_t *) (dst + n),
-				      (const word_t *) (b + n), a + n,
-				      a_offset, nwords);
-      else
-	memxor3_different_alignment_all((word_t *) (dst + n), a + n, b + n,
-					a_offset, b_offset, nwords);
-					
-    }
-  while (n-- > 0)
-    dst[n] = a[n] ^ b[n];
-
-  return dst;
-}