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// Copyright 2018 The dexon-consensus-core Authors
// This file is part of the dexon-consensus-core library.
//
// The dexon-consensus-core library is free software: you can redistribute it
// and/or modify it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation, either version 3 of the License,
// or (at your option) any later version.
//
// The dexon-consensus-core library is distributed in the hope that it will be
// useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
// General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the dexon-consensus-core library. If not, see
// <http://www.gnu.org/licenses/>.
package types
import (
"errors"
"fmt"
)
// ErrComparePositionOnDifferentChains raised when attempting to
// compare two positions with different chain ID.
var ErrComparePositionOnDifferentChains = errors.New(
"position on different chain")
// Position describes the position in the block lattice of an entity.
type Position struct {
ChainID uint32 `json:"chain_id"`
Round uint64 `json:"round"`
Height uint64 `json:"height"`
}
func (pos *Position) String() string {
return fmt.Sprintf("pos[%d:%d:%d]", pos.ChainID, pos.Round, pos.Height)
}
// Equal checks if two positions are equal, it panics when their chainIDs
// are different.
func (pos *Position) Equal(other *Position) bool {
if pos.ChainID != other.ChainID {
panic(ErrComparePositionOnDifferentChains)
}
return pos.Round == other.Round && pos.Height == other.Height
}
// Newer checks if one block is newer than another one on the same chain.
// If two blocks on different chain compared by this function, it would panic.
func (pos *Position) Newer(other *Position) bool {
if pos.ChainID != other.ChainID {
panic(ErrComparePositionOnDifferentChains)
}
return pos.Round > other.Round ||
(pos.Round == other.Round && pos.Height > other.Height)
}
// Clone a position instance.
func (pos *Position) Clone() *Position {
return &Position{
ChainID: pos.ChainID,
Round: pos.Round,
Height: pos.Height,
}
}
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