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Add specialization of SipHash for 256 + 32 bit data

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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.
This commit is contained in:
Pieter Wuille
2017-04-25 11:29:16 -07:00
parent e484652fc3
commit 7e00322906
3 changed files with 59 additions and 0 deletions
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41
src/hash.cpp
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@@ -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;
}