1 files changed, 103 insertions, 0 deletions

diff --git a/CryptoPP/words.h b/CryptoPP/words.h
new file mode 100644
index 000000000..d5fda71da
--- /dev/null
+++ b/CryptoPP/words.h
@@ -0,0 +1,103 @@
+#ifndef CRYPTOPP_WORDS_H
+#define CRYPTOPP_WORDS_H
+
+#include "misc.h"
+
+NAMESPACE_BEGIN(CryptoPP)
+
+inline size_t CountWords(const word *X, size_t N)
+{
+	while (N && X[N-1]==0)
+		N--;
+	return N;
+}
+
+inline void SetWords(word *r, word a, size_t n)
+{
+	for (size_t i=0; i<n; i++)
+		r[i] = a;
+}
+
+inline void CopyWords(word *r, const word *a, size_t n)
+{
+	if (r != a)
+		memcpy(r, a, n*WORD_SIZE);
+}
+
+inline void XorWords(word *r, const word *a, const word *b, size_t n)
+{
+	for (size_t i=0; i<n; i++)
+		r[i] = a[i] ^ b[i];
+}
+
+inline void XorWords(word *r, const word *a, size_t n)
+{
+	for (size_t i=0; i<n; i++)
+		r[i] ^= a[i];
+}
+
+inline void AndWords(word *r, const word *a, const word *b, size_t n)
+{
+	for (size_t i=0; i<n; i++)
+		r[i] = a[i] & b[i];
+}
+
+inline void AndWords(word *r, const word *a, size_t n)
+{
+	for (size_t i=0; i<n; i++)
+		r[i] &= a[i];
+}
+
+inline word ShiftWordsLeftByBits(word *r, size_t n, unsigned int shiftBits)
+{
+	assert (shiftBits<WORD_BITS);
+	word u, carry=0;
+	if (shiftBits)
+		for (size_t i=0; i<n; i++)
+		{
+			u = r[i];
+			r[i] = (u << shiftBits) | carry;
+			carry = u >> (WORD_BITS-shiftBits);
+		}
+	return carry;
+}
+
+inline word ShiftWordsRightByBits(word *r, size_t n, unsigned int shiftBits)
+{
+	assert (shiftBits<WORD_BITS);
+	word u, carry=0;
+	if (shiftBits)
+		for (size_t i=n; i>0; i--)
+		{
+			u = r[i-1];
+			r[i-1] = (u >> shiftBits) | carry;
+			carry = u << (WORD_BITS-shiftBits);
+		}
+	return carry;
+}
+
+inline void ShiftWordsLeftByWords(word *r, size_t n, size_t shiftWords)
+{
+	shiftWords = STDMIN(shiftWords, n);
+	if (shiftWords)
+	{
+		for (size_t i=n-1; i>=shiftWords; i--)
+			r[i] = r[i-shiftWords];
+		SetWords(r, 0, shiftWords);
+	}
+}
+
+inline void ShiftWordsRightByWords(word *r, size_t n, size_t shiftWords)
+{
+	shiftWords = STDMIN(shiftWords, n);
+	if (shiftWords)
+	{
+		for (size_t i=0; i+shiftWords<n; i++)
+			r[i] = r[i+shiftWords];
+		SetWords(r+n-shiftWords, 0, shiftWords);
+	}
+}
+
+NAMESPACE_END
+
+#endif