From 7e0032290669fae5f52c256856c53038511c7db4 Mon Sep 17 00:00:00 2001 From: Pieter Wuille Date: Tue, 25 Apr 2017 11:29:16 -0700 Subject: Add specialization of SipHash for 256 + 32 bit data We'll need a version of SipHash for tuples of 256 bits and 32 bits data, when CCoinsViewCache switches from using txids to COutPoints as keys. --- src/hash.cpp | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) (limited to 'src/hash.cpp') diff --git a/src/hash.cpp b/src/hash.cpp index a14a2386a2..b361c90d16 100644 --- a/src/hash.cpp +++ b/src/hash.cpp @@ -208,3 +208,44 @@ uint64_t SipHashUint256(uint64_t k0, uint64_t k1, const uint256& val) SIPROUND; return v0 ^ v1 ^ v2 ^ v3; } + +uint64_t SipHashUint256Extra(uint64_t k0, uint64_t k1, const uint256& val, uint32_t extra) +{ + /* Specialized implementation for efficiency */ + uint64_t d = val.GetUint64(0); + + uint64_t v0 = 0x736f6d6570736575ULL ^ k0; + uint64_t v1 = 0x646f72616e646f6dULL ^ k1; + uint64_t v2 = 0x6c7967656e657261ULL ^ k0; + uint64_t v3 = 0x7465646279746573ULL ^ k1 ^ d; + + SIPROUND; + SIPROUND; + v0 ^= d; + d = val.GetUint64(1); + v3 ^= d; + SIPROUND; + SIPROUND; + v0 ^= d; + d = val.GetUint64(2); + v3 ^= d; + SIPROUND; + SIPROUND; + v0 ^= d; + d = val.GetUint64(3); + v3 ^= d; + SIPROUND; + SIPROUND; + v0 ^= d; + d = (((uint64_t)36) << 56) | extra; + v3 ^= d; + SIPROUND; + SIPROUND; + v0 ^= d; + v2 ^= 0xFF; + SIPROUND; + SIPROUND; + SIPROUND; + SIPROUND; + return v0 ^ v1 ^ v2 ^ v3; +} -- cgit v1.2.3