1 files changed, 57 insertions, 0 deletions
diff --git a/lib/dns/sec/dnssafe/cantobig.c b/lib/dns/sec/dnssafe/cantobig.c
new file mode 100644
index 00000000..79b760f7
--- /dev/null
+++ b/lib/dns/sec/dnssafe/cantobig.c
@@ -0,0 +1,57 @@
+/* Copyright (C) RSA Data Security, Inc. created 1990, 1996.  This is an
+   unpublished work protected as such under copyright law.  This work
+   contains proprietary, confidential, and trade secret information of
+   RSA Data Security, Inc.  Use, disclosure or reproduction without the
+   express written authorization of RSA Data Security, Inc. is
+   prohibited.
+ */
+
+#include "global.h"
+#include "algae.h"
+#include "bigmath.h"
+
+/* CanonicalToBig () copies a byte vector into a word vector while REVERSING
+     the order of significance.  The byte vector is input MSByte first while
+     the word vector is written out LSWord first. It also adds a leading zero
+     sign bit if necessary.
+   Returns 0, AE_DATA.
+ */
+int CanonicalToBig (wordPointer, wordCount, bytePointer, numBytes)
+UINT2 *wordPointer;
+unsigned int wordCount;
+unsigned char *bytePointer;
+unsigned int numBytes;
+{
+  unsigned int copyCount;
+  
+  if (A_IntegerBits (bytePointer, numBytes) / 16 + 1 > wordCount)
+    return (AE_DATA);
+
+  /* start at end of byte vector */
+  bytePointer += numBytes-1;
+  
+  /* copy as much as possible */
+  copyCount = (wordCount < numBytes / 2) ? wordCount : numBytes / 2;
+  wordCount -= copyCount;
+  numBytes -= 2 * copyCount;
+  while (copyCount--) {
+    /* Copy two bytes.*/
+    *wordPointer++ = (UINT2)*bytePointer + (*(bytePointer - 1) << 8);
+    bytePointer -= 2;
+  }
+  
+  if (wordCount && numBytes & 1) {
+    /* If the number of input bytes was odd.  Copy one last byte.*/
+    *wordPointer++ = (UINT2)*bytePointer--;
+    wordCount--;
+    numBytes--;
+  }
+  
+  /* zero fill remainder of word vector */
+  while (wordCount--)
+    *wordPointer++ = 0;
+  
+  return (0);
+}
+
+