Merge remote-tracking branch 'origin/develop' into release

1 files changed, 63 insertions, 0 deletions

diff --git a/libdevcore/SwarmHash.cpp b/libdevcore/SwarmHash.cpp
new file mode 100644
index 00000000..e7b844eb
--- /dev/null
+++ b/libdevcore/SwarmHash.cpp
@@ -0,0 +1,63 @@
+/*
+	This file is part of cpp-ethereum.
+
+	cpp-ethereum is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	cpp-ethereum is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with cpp-ethereum.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/** @file SwarmHash.cpp
+ */
+
+#include <libdevcore/SwarmHash.h>
+
+#include <libdevcore/SHA3.h>
+
+using namespace std;
+using namespace dev;
+
+
+bytes toLittleEndian(size_t _size)
+{
+	bytes encoded(8);
+	for (size_t i = 0; i < 8; ++i)
+		encoded[i] = (_size >> (8 * i)) & 0xff;
+	return encoded;
+}
+
+h256 swarmHashSimple(bytesConstRef _data, size_t _size)
+{
+	return keccak256(toLittleEndian(_size) + _data.toBytes());
+}
+
+h256 swarmHashIntermediate(bytes const& _input, size_t _offset, size_t _length)
+{
+	if (_length <= 0x1000)
+		return swarmHashSimple(bytesConstRef(_input.data() + _offset, _length), _length);
+	else
+	{
+		bytes innerNodes;
+		size_t maxRepresentedSize = 0x1000;
+		while (maxRepresentedSize * (0x1000 / 32) < _length)
+			maxRepresentedSize *= (0x1000 / 32);
+		for (size_t i = 0; i < _length; i += maxRepresentedSize)
+		{
+			size_t size = std::min(maxRepresentedSize, _length - i);
+			innerNodes += swarmHashIntermediate(_input, _offset + i, size).asBytes();
+		}
+		return swarmHashSimple(bytesConstRef(&innerNodes), _length);
+	}
+}
+
+h256 dev::swarmHash(bytes const& _input)
+{
+	return swarmHashIntermediate(_input, 0, _input.size());
+}