From 851f567904d2e6ef236fede79b02d638c71e4e2f Mon Sep 17 00:00:00 2001
From: weidai <weidai@57ff6487-cd31-0410-9ec3-f628ee90f5f0>
Date: Sun, 15 Apr 2007 22:54:31 +0000
Subject: SSE2 optimizations

git-svn-id: svn://svn.code.sf.net/p/cryptopp/code/trunk/c5@282 57ff6487-cd31-0410-9ec3-f628ee90f5f0
---
 strciphr.cpp | 80 ++++++++++++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 64 insertions(+), 16 deletions(-)

(limited to 'strciphr.cpp')

diff --git a/strciphr.cpp b/strciphr.cpp
index b25017e..6294785 100644
--- a/strciphr.cpp
+++ b/strciphr.cpp
@@ -37,6 +37,57 @@ byte AdditiveCipherTemplate<S>::GenerateByte()
 	return *(KeystreamBufferEnd()-m_leftOver--);
 }
 
+template <class S>
+void AdditiveCipherTemplate<S>::GenerateBlock(byte *outString, size_t length)
+{
+	if (m_leftOver > 0)
+	{
+		size_t len = STDMIN(m_leftOver, length);
+		memcpy(outString, KeystreamBufferEnd()-m_leftOver, len);
+		length -= len;
+		m_leftOver -= len;
+		outString += len;
+
+		if (!length)
+			return;
+	}
+	assert(m_leftOver == 0);
+
+	PolicyInterface &policy = this->AccessPolicy();
+	unsigned int bytesPerIteration = policy.GetBytesPerIteration();
+
+	if (length >= bytesPerIteration)
+	{
+		size_t iterations = length / bytesPerIteration;
+
+		policy.WriteKeystream(outString, iterations);
+
+		outString += iterations * bytesPerIteration;
+		length -= iterations * bytesPerIteration;
+
+		if (!length)
+			return;
+	}
+
+	unsigned int bufferByteSize = GetBufferByteSize(policy);
+	unsigned int bufferIterations = policy.GetIterationsToBuffer();
+
+	while (length >= bufferByteSize)
+	{
+		policy.WriteKeystream(m_buffer, bufferIterations);
+		memcpy(outString, KeystreamBufferBegin(), bufferByteSize);
+		length -= bufferByteSize;
+		outString += bufferByteSize;
+	}
+
+	if (length > 0)
+	{
+		policy.WriteKeystream(m_buffer, bufferIterations);
+		memcpy(outString, KeystreamBufferBegin(), length);
+		m_leftOver = bytesPerIteration - length;
+	}
+}
+
 template <class S>
 void AdditiveCipherTemplate<S>::ProcessData(byte *outString, const byte *inString, size_t length)
 {
@@ -48,29 +99,26 @@ void AdditiveCipherTemplate<S>::ProcessData(byte *outString, const byte *inStrin
 		m_leftOver -= len;
 		inString += len;
 		outString += len;
-	}
-
-	if (!length)
-		return;
 
+		if (!length)
+			return;
+	}
 	assert(m_leftOver == 0);
 
 	PolicyInterface &policy = this->AccessPolicy();
 	unsigned int bytesPerIteration = policy.GetBytesPerIteration();
-	unsigned int alignment = policy.GetAlignment();
 
-	if (policy.CanOperateKeystream() && length >= bytesPerIteration && IsAlignedOn(outString, alignment))
+	if (policy.CanOperateKeystream() && length >= bytesPerIteration)
 	{
-		if (IsAlignedOn(inString, alignment))
-			policy.OperateKeystream(XOR_KEYSTREAM, outString, inString, length / bytesPerIteration);
-		else
-		{
-			memcpy(outString, inString, length);
-			policy.OperateKeystream(XOR_KEYSTREAM_INPLACE, outString, outString, length / bytesPerIteration);
-		}
-		inString += length - length % bytesPerIteration;
-		outString += length - length % bytesPerIteration;
-		length %= bytesPerIteration;
+		size_t iterations = length / bytesPerIteration;
+		unsigned int alignment = policy.GetAlignment();
+		KeystreamOperation operation = KeystreamOperation((IsAlignedOn(inString, alignment) * 2) | (int)IsAlignedOn(outString, alignment));
+
+		policy.OperateKeystream(operation, outString, inString, iterations);
+
+		inString += iterations * bytesPerIteration;
+		outString += iterations * bytesPerIteration;
+		length -= iterations * bytesPerIteration;
 
 		if (!length)
 			return;
-- 
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