github.com/annchain/OG@v0.0.9/vm/ovm/gaspool.go (about)

     1  // Copyright 2015 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package ovm
    18  
    19  import (
    20  	"fmt"
    21  	"github.com/annchain/OG/vm/types"
    22  	"math"
    23  )
    24  
    25  // GasPool tracks the amount of gas available during execution of the transactions
    26  // in a block. The zero value is a pool with zero gas available.
    27  type GasPool uint64
    28  
    29  // AddGas makes gas available for execution.
    30  func (gp *GasPool) AddGas(amount uint64) *GasPool {
    31  	if uint64(*gp) > math.MaxUint64-amount {
    32  		panic("gas pool pushed above uint64")
    33  	}
    34  	*(*uint64)(gp) += amount
    35  	return gp
    36  }
    37  
    38  // SubGas deducts the given amount from the pool if enough gas is
    39  // available and returns an error otherwise.
    40  func (gp *GasPool) SubGas(amount uint64) error {
    41  	if uint64(*gp) < amount {
    42  		return types.ErrGasLimitReached
    43  	}
    44  	*(*uint64)(gp) -= amount
    45  	return nil
    46  }
    47  
    48  // Gas returns the amount of gas remaining in the pool.
    49  func (gp *GasPool) Gas() uint64 {
    50  	return uint64(*gp)
    51  }
    52  
    53  func (gp *GasPool) String() string {
    54  	return fmt.Sprintf("%d", *gp)
    55  }