MurmurHash : Added string constructor and fromString function.

Author: proberts-cinesite

Changes

@@ -1,6 +1,11 @@
 10.4.2.1 (relative to 10.4.2.0)
 ========
 
+Improvements
+------------
+
+- Added string constructor and `fromString` function to `IECore.MurmurHash`.
+
 Build
 -----
 

include/IECore/MurmurHash.h

@@ -61,6 +61,9 @@ class IECORE_API MurmurHash
 		inline MurmurHash();
 		inline MurmurHash( const MurmurHash &other );
 
+		// Construct directly from string representation
+		inline explicit MurmurHash( const std::string &repr );
+
 		// Construct directly from known internal values
 		inline MurmurHash( uint64_t h1, uint64_t h2 );
 
@@ -84,6 +87,7 @@ class IECORE_API MurmurHash
 		inline bool operator < ( const MurmurHash &other ) const;
 
 		std::string toString() const;
+		void fromString( const std::string &repr );
 
 		// Access internal storage for special cases
 		inline uint64_t h1() const;

include/IECore/MurmurHash.inl

@@ -79,6 +79,12 @@ inline MurmurHash::MurmurHash( const MurmurHash &other )
 {
 }
 
+inline MurmurHash::MurmurHash( const std::string &repr )
+	:	m_h1( 0 ), m_h2( 0 )
+{
+	fromString( repr );
+}
+
 inline MurmurHash::MurmurHash( uint64_t h1, uint64_t h2 )
     :   m_h1( h1 ), m_h2( h2 )
 {

src/IECore/MurmurHash.cpp

@@ -46,6 +46,16 @@ std::string MurmurHash::toString() const
 	return s.str();
 }
 
+void MurmurHash::fromString( const std::string &repr )
+{
+	std::stringstream s;
+	s.str( repr.substr( 0, 16 ) );
+	s >> std::hex >> m_h1;
+	s.clear();
+	s.str( repr.substr( 16, 16 ) );
+	s >> std::hex >> m_h2;
+}
+
 std::ostream &IECore::operator << ( std::ostream &o, const MurmurHash &hash )
 {
 	o << hash.toString();

src/IECorePython/MurmurHashBinding.cpp

@@ -128,6 +128,7 @@ void IECorePython::bindMurmurHash()
 	class_<MurmurHash>( "MurmurHash" )
 		.def( init<>() )
 		.def( init<const MurmurHash &>() )
+		.def( init<const std::string &>() )
 		.def( init<uint64_t, uint64_t>() )
 		.def( "append", (MurmurHash &(MurmurHash::*)( const float & ))&MurmurHash::append, return_self<>() )
 		.def( "append", (MurmurHash &(MurmurHash::*)( const double & ))&MurmurHash::append, return_self<>() )
@@ -198,6 +199,7 @@ void IECorePython::bindMurmurHash()
 		.def( "__str__", &MurmurHash::toString )
 		.def( "__hash__", &hash )
 		.def( "toString", &MurmurHash::toString )
+		.def( "fromString", &MurmurHash::fromString )
 		.def( "h1", &MurmurHash::h1 )
 		.def( "h2", &MurmurHash::h2 )
 	;

test/IECore/MurmurHashTest.py

@@ -45,6 +45,16 @@ def testConstructor( self ) :
 		self.assertEqual( str( h ), "0" * 32 )
 		self.assertEqual( h, IECore.MurmurHash() )
 
+	def testStringConstructor( self ) :
+
+		h = IECore.MurmurHash()
+		h.append( 1 )
+		h.append( "hello" )
+
+		s = h.toString()
+		hs = IECore.MurmurHash( s )
+		self.assertEqual( h, hs )
+
 	def testCopyConstructor( self ) :
 
 		h = IECore.MurmurHash()
@@ -54,6 +64,17 @@ def testCopyConstructor( self ) :
 		self.assertEqual( h, IECore.MurmurHash( h ) )
 		self.assertNotEqual( h, IECore.MurmurHash() )
 
+	def testFromString( self ) :
+
+		h = IECore.MurmurHash()
+		h.append( 1 )
+		h.append( "hello" )
+
+		s = h.toString()
+		hs = IECore.MurmurHash()
+		hs.fromString( s )
+		self.assertEqual( h, hs )
+
 	def testAppend( self ) :
 
 		h = IECore.MurmurHash()