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authorMatt Corallo <git@bluematt.me>2012-11-02 18:33:50 -0400
committerMatt Corallo <git@bluematt.me>2013-01-16 12:48:02 -0500
commitb1f99bed6f0fbbe94e6a3161b49b3f225dec8374 (patch)
treeae47ef2b17af591fdcd3a07e1e957513a694304d /src/bloom.h
parent4c8fc1a5885634c3b463d5d44337d81cc5b1456b (diff)
Add a nTweak to bloom filters to tweak the seed.
Diffstat (limited to 'src/bloom.h')
-rw-r--r--src/bloom.h6
1 files changed, 5 insertions, 1 deletions
diff --git a/src/bloom.h b/src/bloom.h
index 1a8a562dad..a59b1d99f5 100644
--- a/src/bloom.h
+++ b/src/bloom.h
@@ -33,6 +33,7 @@ class CBloomFilter
private:
std::vector<unsigned char> vData;
unsigned int nHashFuncs;
+ unsigned int nTweak;
unsigned int Hash(unsigned int nHashNum, const std::vector<unsigned char>& vDataToHash) const;
@@ -41,7 +42,9 @@ public:
// Note that if the given parameters will result in a filter outside the bounds of the protocol limits,
// the filter created will be as close to the given parameters as possible within the protocol limits.
// This will apply if nFPRate is very low or nElements is unreasonably high.
- CBloomFilter(unsigned int nElements, double nFPRate);
+ // nTweak is a constant which is added to the seed value passed to the hash function
+ // It should generally always be a random value (and is largely only exposed for unit testing)
+ CBloomFilter(unsigned int nElements, double nFPRate, unsigned int nTweak);
// Using a filter initialized with this results in undefined behavior
// Should only be used for deserialization
CBloomFilter() {}
@@ -50,6 +53,7 @@ public:
(
READWRITE(vData);
READWRITE(nHashFuncs);
+ READWRITE(nTweak);
)
void insert(const std::vector<unsigned char>& vKey);