Use unordered_map for CCoinsViewCache with salted hash

This commit is contained in:
Pieter Wuille 2014-07-09 17:25:09 +02:00
parent bdd5b587fc
commit bc42503f6a
4 changed files with 66 additions and 4 deletions

View file

@ -4,6 +4,8 @@
#include "coins.h"
#include "random.h"
#include <assert.h>
// 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))

View file

@ -13,6 +13,7 @@
#include <stdint.h>
#include <boost/foreach.hpp>
#include <boost/unordered_map.hpp>
/** pruned version of CTransaction: only retains metadata and unspent transaction outputs
*
@ -239,7 +240,19 @@ public:
}
};
typedef std::map<uint256,CCoins> CCoinsMap;
class CCoinsKeyHasher
{
private:
uint256 salt;
public:
CCoinsKeyHasher();
uint64_t operator()(const uint256& key) const {
return key.GetHash(salt);
}
};
typedef boost::unordered_map<uint256, CCoins, CCoinsKeyHasher> CCoinsMap;
struct CCoinsStats
{

View file

@ -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);
}

View file

@ -21,7 +21,7 @@ public:
template<unsigned int BITS>
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