#include <hasher.h>

Public Member Functions
	SaltedOutpointHasher ()

size_t	operator() (const COutPoint &id) const noexcept
	This must return size_t. More...

Private Attributes
const uint64_t	k0
	Salt. More...

const uint64_t	k1

Detailed Description

Definition at line 26 of file hasher.h.

Constructor & Destructor Documentation

◆ SaltedOutpointHasher()

SaltedOutpointHasher::SaltedOutpointHasher ( )

Definition at line 12 of file hasher.cpp.

Member Function Documentation

◆ operator()()

size_t SaltedOutpointHasher::operator() ( const COutPoint & id ) const

inlinenoexcept

This must return size_t.

With Boost 1.46 on 32-bit systems the unordered_map will behave unpredictably if the custom hasher returns a uint64_t, resulting in failures when syncing the chain (#4634).

Having the hash noexcept allows libstdc++'s unordered_map to recalculate the hash during rehash, so it does not have to cache the value. This reduces node's memory by sizeof(size_t). The required recalculation has a slight performance penalty (around 1.6%), but this is compensated by memory savings of about 9% which allow for a larger dbcache setting.