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authorchriseth <c@ethdev.com>2016-11-15 21:55:19 +0800
committerchriseth <c@ethdev.com>2016-11-15 21:55:51 +0800
commit518fe2aab7b96dc9cd259049dec80be509860a43 (patch)
tree4e290aee6d7799a5c43bae9cd12d1e7265828b79 /libdevcore
parent0072160d7772b2f30c2c6af4428728cb31641696 (diff)
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Correct implementation of swarm hash.
Diffstat (limited to 'libdevcore')
-rw-r--r--libdevcore/SwarmHash.cpp38
1 files changed, 16 insertions, 22 deletions
diff --git a/libdevcore/SwarmHash.cpp b/libdevcore/SwarmHash.cpp
index 583d84b1..e7b844eb 100644
--- a/libdevcore/SwarmHash.cpp
+++ b/libdevcore/SwarmHash.cpp
@@ -38,32 +38,26 @@ h256 swarmHashSimple(bytesConstRef _data, size_t _size)
return keccak256(toLittleEndian(_size) + _data.toBytes());
}
-h256 dev::swarmHash(bytes const& _input)
+h256 swarmHashIntermediate(bytes const& _input, size_t _offset, size_t _length)
{
- bytes data = _input;
- size_t lastChunkSize = 0;
- size_t level = 0;
- do
+ if (_length <= 0x1000)
+ return swarmHashSimple(bytesConstRef(_input.data() + _offset, _length), _length);
+ else
{
bytes innerNodes;
- size_t i = 0;
- do
+ size_t maxRepresentedSize = 0x1000;
+ while (maxRepresentedSize * (0x1000 / 32) < _length)
+ maxRepresentedSize *= (0x1000 / 32);
+ for (size_t i = 0; i < _length; i += maxRepresentedSize)
{
- 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;
+ size_t size = std::min(maxRepresentedSize, _length - i);
+ innerNodes += swarmHashIntermediate(_input, _offset + i, size).asBytes();
}
- while (i < data.size());
- data = std::move(innerNodes);
- level++;
+ return swarmHashSimple(bytesConstRef(&innerNodes), _length);
}
- while (data.size() > 32);
- return h256(data);
+}
+
+h256 dev::swarmHash(bytes const& _input)
+{
+ return swarmHashIntermediate(_input, 0, _input.size());
}