From bc42503f6ab304608c321986a870795e45f5a016 Mon Sep 17 00:00:00 2001 From: Pieter Wuille Date: Wed, 9 Jul 2014 17:25:09 +0200 Subject: [PATCH] Use unordered_map for CCoinsViewCache with salted hash --- src/coins.cpp | 8 ++++++-- src/coins.h | 15 ++++++++++++++- src/uint256.cpp | 43 +++++++++++++++++++++++++++++++++++++++++++ src/uint256.h | 4 +++- 4 files changed, 66 insertions(+), 4 deletions(-) diff --git a/src/coins.cpp b/src/coins.cpp index 13a4ea95c..e76d8c7ef 100644 --- a/src/coins.cpp +++ b/src/coins.cpp @@ -4,6 +4,8 @@ #include "coins.h" +#include "random.h" + #include // calculate number of bytes for the bitmask, and its number of non-zero bytes @@ -69,6 +71,8 @@ void CCoinsViewBacked::SetBackend(CCoinsView &viewIn) { base = &viewIn; } bool CCoinsViewBacked::BatchWrite(const CCoinsMap &mapCoins, const uint256 &hashBlock) { return base->BatchWrite(mapCoins, hashBlock); } bool CCoinsViewBacked::GetStats(CCoinsStats &stats) { return base->GetStats(stats); } +CCoinsKeyHasher::CCoinsKeyHasher() : salt(GetRandHash()) {} + CCoinsViewCache::CCoinsViewCache(CCoinsView &baseIn, bool fDummy) : CCoinsViewBacked(baseIn), hashBlock(0) { } bool CCoinsViewCache::GetCoins(const uint256 &txid, CCoins &coins) { @@ -84,8 +88,8 @@ bool CCoinsViewCache::GetCoins(const uint256 &txid, CCoins &coins) { } CCoinsMap::iterator CCoinsViewCache::FetchCoins(const uint256 &txid) { - CCoinsMap::iterator it = cacheCoins.lower_bound(txid); - if (it != cacheCoins.end() && it->first == txid) + CCoinsMap::iterator it = cacheCoins.find(txid); + if (it != cacheCoins.end()) return it; CCoins tmp; if (!base->GetCoins(txid,tmp)) diff --git a/src/coins.h b/src/coins.h index c57a5ec72..9f90fe6bd 100644 --- a/src/coins.h +++ b/src/coins.h @@ -13,6 +13,7 @@ #include #include +#include /** pruned version of CTransaction: only retains metadata and unspent transaction outputs * @@ -239,7 +240,19 @@ public: } }; -typedef std::map CCoinsMap; +class CCoinsKeyHasher +{ +private: + uint256 salt; + +public: + CCoinsKeyHasher(); + uint64_t operator()(const uint256& key) const { + return key.GetHash(salt); + } +}; + +typedef boost::unordered_map CCoinsMap; struct CCoinsStats { diff --git a/src/uint256.cpp b/src/uint256.cpp index 3392f1e9b..08c05594f 100644 --- a/src/uint256.cpp +++ b/src/uint256.cpp @@ -290,3 +290,46 @@ uint32_t uint256::GetCompact(bool fNegative) const nCompact |= (fNegative && (nCompact & 0x007fffff) ? 0x00800000 : 0); return nCompact; } + +static void inline HashMix(uint32_t& a, uint32_t& b, uint32_t& c) +{ + // Taken from lookup3, by Bob Jenkins. + a -= c; a ^= ((c << 4) | (c >> 28)); c += b; + b -= a; b ^= ((a << 6) | (a >> 26)); a += c; + c -= b; c ^= ((b << 8) | (b >> 24)); b += a; + a -= c; a ^= ((c << 16) | (c >> 16)); c += b; + b -= a; b ^= ((a << 19) | (a >> 13)); a += c; + c -= b; c ^= ((b << 4) | (b >> 28)); b += a; +} + +static void inline HashFinal(uint32_t& a, uint32_t& b, uint32_t& c) +{ + // Taken from lookup3, by Bob Jenkins. + c ^= b; c -= ((b << 14) | (b >> 18)); + a ^= c; a -= ((c << 11) | (c >> 21)); + b ^= a; b -= ((a << 25) | (a >> 7)); + c ^= b; c -= ((b << 16) | (b >> 16)); + a ^= c; a -= ((c << 4) | (c >> 28)); + b ^= a; b -= ((a << 14) | (a >> 18)); + c ^= b; c -= ((b << 24) | (b >> 8)); +} + +uint64_t uint256::GetHash(const uint256 &salt) const +{ + uint32_t a, b, c; + a = b = c = 0xdeadbeef + (WIDTH << 2); + + a += pn[0] ^ salt.pn[0]; + b += pn[1] ^ salt.pn[1]; + c += pn[2] ^ salt.pn[2]; + HashMix(a, b, c); + a += pn[3] ^ salt.pn[3]; + b += pn[4] ^ salt.pn[4]; + c += pn[5] ^ salt.pn[5]; + HashMix(a, b, c); + a += pn[6] ^ salt.pn[6]; + b += pn[7] ^ salt.pn[7]; + HashFinal(a, b, c); + + return ((((uint64_t)b) << 32) | c); +} diff --git a/src/uint256.h b/src/uint256.h index 82db7758c..ad0a56f44 100644 --- a/src/uint256.h +++ b/src/uint256.h @@ -21,7 +21,7 @@ public: template class base_uint { -private: +protected: enum { WIDTH=BITS/32 }; uint32_t pn[WIDTH]; public: @@ -322,6 +322,8 @@ public: // implementation accident. uint256& SetCompact(uint32_t nCompact, bool *pfNegative = NULL, bool *pfOverflow = NULL); uint32_t GetCompact(bool fNegative = false) const; + + uint64_t GetHash(const uint256& salt) const; }; #endif