added DigestEngine::digestFromHex

Foundation/include/Poco/DigestEngine.h

@@ -1,7 +1,7 @@
 //
 // DigestEngine.h
 //
-// $Id: //poco/svn/Foundation/include/Poco/DigestEngine.h#2 $
+// $Id: //poco/Main/Foundation/include/Poco/DigestEngine.h#3 $
 //
 // Library: Foundation
 // Package: Crypt
@@ -85,6 +85,9 @@ public:
 	static std::string digestToHex(const Digest& bytes);
 		/// Converts a message digest into a string of hexadecimal numbers.
 
+	static Digest digestFromHex(const std::string& digest);
+		/// Converts a string created by digestToHex back to its Digest presentation
+
 protected:
 	virtual void updateImpl(const void* data, unsigned length) = 0;
 		/// Updates the digest with the given data. Must be implemented

Foundation/src/DigestEngine.cpp

@@ -1,7 +1,7 @@
 //
 // DigestEngine.cpp
 //
-// $Id: //poco/svn/Foundation/src/DigestEngine.cpp#2 $
+// $Id: //poco/Main/Foundation/src/DigestEngine.cpp#11 $
 //
 // Library: Foundation
 // Package: Crypt
@@ -35,6 +35,7 @@
 
 
 #include "Poco/DigestEngine.h"
+#include "Poco/Exception.h"
 
 
 namespace Poco {
@@ -65,4 +66,39 @@ std::string DigestEngine::digestToHex(const Digest& bytes)
 }
 
 
+DigestEngine::Digest DigestEngine::digestFromHex(const std::string& digest)
+{
+	if (digest.size() % 2 != 0)
+		throw DataFormatException();
+	Digest result;
+	result.reserve(digest.size()/2);
+	for (std::size_t i = 0; i < digest.size(); ++i)
+	{
+		int c = 0;
+		// first upper 4 bits
+		if (digest[i] >= '0' && digest[i] <= '9')
+			c = digest[i] - '0';
+		else if (digest[i] >= 'a' && digest[i] <= 'f')
+			c = digest[i] - 'a'+10;
+		else if (digest[i] >= 'A' && digest[i] <= 'F')
+			c = digest[i] - 'A'+10;
+		else
+			throw DataFormatException();
+		c <<= 4;
+		++i;
+		if (digest[i] >= '0' && digest[i] <= '9')
+			c += digest[i] - '0';
+		else if (digest[i] >= 'a' && digest[i] <= 'f')
+			c += digest[i] - 'a'+10;
+		else if (digest[i] >= 'A' && digest[i] <= 'F')
+			c += digest[i] - 'A'+10;
+		else
+			throw DataFormatException();
+
+		result.push_back(static_cast<unsigned char>(c));
+	}
+	return result;
+}
+
+
 } // namespace Poco

Foundation/testsuite/src/DigestStreamTest.cpp

@@ -1,7 +1,7 @@
 //
 // DigestStreamTest.cpp
 //
-// $Id: //poco/svn/Foundation/testsuite/src/DigestStreamTest.cpp#2 $
+// $Id: //poco/Main/Foundation/testsuite/src/DigestStreamTest.cpp#10 $
 //
 // Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
 // and Contributors.
@@ -93,6 +93,15 @@ void DigestStreamTest::testOutputStream2()
 }
 
 
+void DigestStreamTest::testToFromHex()
+{
+	std::string digest("c3fcd3d76192e4007dfb496cca67e13b");
+	Poco::DigestEngine::Digest dig = DigestEngine::digestFromHex(digest);
+	std::string digest2 = DigestEngine::digestToHex(dig);
+	assert (digest == digest2);
+}
+
+
 void DigestStreamTest::setUp()
 {
 }
@@ -110,6 +119,7 @@ CppUnit::Test* DigestStreamTest::suite()
 	CppUnit_addTest(pSuite, DigestStreamTest, testInputStream);
 	CppUnit_addTest(pSuite, DigestStreamTest, testOutputStream1);
 	CppUnit_addTest(pSuite, DigestStreamTest, testOutputStream2);
+	CppUnit_addTest(pSuite, DigestStreamTest, testToFromHex);
 
 	return pSuite;
 }

Foundation/testsuite/src/DigestStreamTest.h

@@ -1,7 +1,7 @@
 //
 // DigestStreamTest.h
 //
-// $Id: //poco/svn/Foundation/testsuite/src/DigestStreamTest.h#2 $
+// $Id: //poco/Main/Foundation/testsuite/src/DigestStreamTest.h#9 $
 //
 // Definition of the DigestStreamTest class.
 //
@@ -49,6 +49,7 @@ public:
 	void testInputStream();
 	void testOutputStream1();
 	void testOutputStream2();
+	void testToFromHex();
 
 	void setUp();
 	void tearDown();