github.com/vantum/vantum@v0.0.0-20180815184342-fe37d5f7a990/core/vm/intpool.go (about)

     1  // Copyright 2017 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 vm
    18  
    19  import "math/big"
    20  
    21  var checkVal = big.NewInt(-42)
    22  
    23  const poolLimit = 256
    24  
    25  // intPool is a pool of big integers that
    26  // can be reused for all big.Int operations.
    27  type intPool struct {
    28  	pool *Stack
    29  }
    30  
    31  func newIntPool() *intPool {
    32  	return &intPool{pool: newstack()}
    33  }
    34  
    35  func (p *intPool) get() *big.Int {
    36  	if p.pool.len() > 0 {
    37  		return p.pool.pop()
    38  	}
    39  	return new(big.Int)
    40  }
    41  func (p *intPool) put(is ...*big.Int) {
    42  	if len(p.pool.data) > poolLimit {
    43  		return
    44  	}
    45  
    46  	for _, i := range is {
    47  		// verifyPool is a build flag. Pool verification makes sure the integrity
    48  		// of the integer pool by comparing values to a default value.
    49  		if verifyPool {
    50  			i.Set(checkVal)
    51  		}
    52  
    53  		p.pool.push(i)
    54  	}
    55  }