peerplays_migrated/libraries/chain/include/graphene/chain/vote_count.hpp
2016-02-15 15:33:21 -05:00

77 lines
2.6 KiB
C++

/*
* Copyright (c) 2015 Cryptonomex, Inc., and contributors.
*
* The MIT License
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#pragma once
#include <graphene/chain/protocol/authority.hpp>
namespace graphene { namespace chain {
/**
* Keep track of vote totals in internal authority object. See #533.
*/
struct vote_counter
{
template< typename Component >
void add( Component who, uint64_t votes )
{
if( votes == 0 )
return;
assert( votes <= last_votes );
last_votes = votes;
if( bitshift == -1 )
bitshift = std::max(int(boost::multiprecision::detail::find_msb( votes )) - 15, 0);
uint64_t scaled_votes = std::max( votes >> bitshift, uint64_t(1) );
assert( scaled_votes <= std::numeric_limits<weight_type>::max() );
total_votes += scaled_votes;
assert( total_votes <= std::numeric_limits<uint32_t>::max() );
auth.add_authority( who, weight_type( scaled_votes ) );
}
/**
* Write into out_auth, but only if we have at least one member.
*/
void finish( authority& out_auth )
{
if( total_votes == 0 )
return;
assert( total_votes <= std::numeric_limits<uint32_t>::max() );
uint32_t weight = uint32_t( total_votes );
weight = (weight >> 1)+1;
auth.weight_threshold = weight;
out_auth = auth;
}
bool is_empty()const
{
return (total_votes == 0);
}
uint64_t last_votes = std::numeric_limits<uint64_t>::max();
uint64_t total_votes = 0;
int8_t bitshift = -1;
authority auth;
};
} } // graphene::chain