68 lines
2.0 KiB
Go
68 lines
2.0 KiB
Go
// Copyright 2017 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package vm
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import "math/big"
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var checkVal = big.NewInt(-42)
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const poolLimit = 256
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// intPool is a pool of big integers that
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// can be reused for all big.Int operations.
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type intPool struct {
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pool *Stack
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}
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func newIntPool() *intPool {
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return &intPool{pool: newstack()}
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}
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// get retrieves a big int from the pool, allocating one if the pool is empty.
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// Note, the returned int's value is arbitrary and will not be zeroed!
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func (p *intPool) get() *big.Int {
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if p.pool.len() > 0 {
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return p.pool.pop()
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}
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return new(big.Int)
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}
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// getZero retrieves a big int from the pool, setting it to zero or allocating
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// a new one if the pool is empty.
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func (p *intPool) getZero() *big.Int {
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if p.pool.len() > 0 {
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return p.pool.pop().SetUint64(0)
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}
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return new(big.Int)
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}
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// put returns an allocated big int to the pool to be later reused by get calls.
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// Note, the values as saved as is; neither put nor get zeroes the ints out!
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func (p *intPool) put(is ...*big.Int) {
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if len(p.pool.data) > poolLimit {
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return
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}
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for _, i := range is {
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// verifyPool is a build flag. Pool verification makes sure the integrity
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// of the integer pool by comparing values to a default value.
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if verifyPool {
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i.Set(checkVal)
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}
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p.pool.push(i)
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}
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}
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