Multi-level swarm hash.

4 files changed, 103 insertions, 10 deletions

diff --git a/libdevcore/SHA3.cpp b/libdevcore/SHA3.cpp
index 3b12f39f..96c7b764 100644
--- a/libdevcore/SHA3.cpp
+++ b/libdevcore/SHA3.cpp
@@ -238,4 +238,47 @@ bool keccak256(bytesConstRef _input, bytesRef o_output)
 	return true;
 }
 
+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 swarmHash(bytes const& _input)
+{
+	bytes data = _input;
+	size_t lastChunkSize = 0;
+	size_t level = 0;
+	do
+	{
+		bytes innerNodes;
+		size_t i = 0;
+		do
+		{
+			size_t bytes = std::min<size_t>(0x1000, data.size() - i);
+			size_t size = bytes << (7 * level);
+			if (i + 0x1000 >= data.size())
+			{
+				// last node
+				size = level == 0 ? bytes : ((bytes - 32) << (7 * level)) + lastChunkSize;
+				lastChunkSize = size;
+			}
+			innerNodes += swarmHashSimple(bytesConstRef(_input.data() + i, bytes), size).asBytes();
+			i += 0x1000;
+		}
+		while (i < data.size());
+		data = std::move(innerNodes);
+		level++;
+	}
+	while (data.size() > 32);
+	return h256(data);
+}
+
 }
diff --git a/libdevcore/SHA3.h b/libdevcore/SHA3.h
index e3ff1335..ea0c761d 100644
--- a/libdevcore/SHA3.h
+++ b/libdevcore/SHA3.h
@@ -53,12 +53,5 @@ inline std::string keccak256(std::string const& _input, bool _isNibbles) { retur
 /// Calculate SHA3-256 MAC
 inline void keccak256mac(bytesConstRef _secret, bytesConstRef _plain, bytesRef _output) { keccak256(_secret.toBytes() + _plain.toBytes()).ref().populate(_output); }
 
-h256 swarmHash(bytes const& _data)
-{
-	bytes size(8);
-	for (size_t i = 0; i < 8; ++i)
-		size[i] = (_data.size() >> (8 * i)) & 0xff;
-
-	return keccak256(size + _data);
-}
+h256 swarmHash(bytes const& _data);
 }
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index e67a04d4..33af9981 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -1,9 +1,10 @@
 cmake_policy(SET CMP0015 NEW)
 
 aux_source_directory(. SRC_LIST)
-aux_source_directory(contracts SRC_LIST)
-aux_source_directory(libsolidity SRC_LIST)
+aux_source_directory(libdevcore SRC_LIST)
 aux_source_directory(libevmasm SRC_LIST)
+aux_source_directory(libsolidity SRC_LIST)
+aux_source_directory(contracts SRC_LIST)
 
 get_filename_component(TESTS_DIR "${CMAKE_CURRENT_SOURCE_DIR}" ABSOLUTE)
 
diff --git a/test/libdevcore/SwarmHash.cpp b/test/libdevcore/SwarmHash.cpp
new file mode 100644
index 00000000..47b2baa7
--- /dev/null
+++ b/test/libdevcore/SwarmHash.cpp
@@ -0,0 +1,56 @@
+/*
+	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/>.
+*/
+/**
+ * Unit tests for the swarm hash computation routine.
+ */
+
+#include <libdevcore/SHA3.h>
+
+#include "../TestHelper.h"
+
+using namespace std;
+
+namespace dev
+{
+namespace test
+{
+
+BOOST_AUTO_TEST_SUITE(SwarmHash)
+
+string swarmHashHex(bytes const& _input)
+{
+	return toHex(swarmHash(_input).asBytes());
+}
+
+BOOST_AUTO_TEST_CASE(test_zeros)
+{
+	BOOST_CHECK_EQUAL(swarmHashHex(bytes()), string("011b4d03dd8c01f1049143cf9c4c817e4b167f1d1b83e5c6f0f10d89ba1e7bce"));
+	BOOST_CHECK_EQUAL(swarmHashHex(bytes(0x1000 - 1, 0)), string("32f0faabc4265ac238cd945087133ce3d7e9bb2e536053a812b5373c54043adb"));
+	BOOST_CHECK_EQUAL(swarmHashHex(bytes(0x1000, 0)), string("411dd45de7246e94589ff5888362c41e85bd3e582a92d0fda8f0e90b76439bec"));
+	BOOST_CHECK_EQUAL(swarmHashHex(bytes(0x1000 + 1, 0)), string("970b0b1fe0bf90549af9aba54e8ce18884cce97d63069efe92f73fd50037c3e2"));
+	BOOST_CHECK_EQUAL(swarmHashHex(bytes(0x2000 - 1, 0)), string("1e7bd4d46836b63a2e7c313b68d24ad6be56ed6c8b30634005fd213bb580b0b4"));
+	BOOST_CHECK_EQUAL(swarmHashHex(bytes(0x2000, 0)), string("ab184c15eee316dd54e8887614a535f589478e99b922a1ede30ec418344c8324"));
+	BOOST_CHECK_EQUAL(swarmHashHex(bytes(0x2000 + 1, 0)), string("c8915d9244ad5d7428a41b207e083de6eafffac629b45ad462062ea8dc5ac4a3"));
+	BOOST_CHECK_EQUAL(swarmHashHex(bytes(0x80000, 0)), string("d0bf003bbc34a68f608f8bc88b497c19ce4ad61f38436ee3120b33db9cc9a116"));
+	BOOST_CHECK_EQUAL(swarmHashHex(bytes(0x80020, 0)), string("d001908f9942ad56d5343574e33bd74b30092115b1c29a67c20869a9ddbbedc3"));
+	BOOST_CHECK_EQUAL(swarmHashHex(bytes(0x800020, 0)), string("cdeedeccfe3eaa1c4095713af579b9c2b151d2b3f45ce6652ba2f5cd537a60ba"));
+}
+
+BOOST_AUTO_TEST_SUITE_END()
+
+}
+}