ac697326a6
Reduced big int allocation by making stack items modifiable. Instead of adding items such as `common.Big0` to the stack, `new(big.Int)` is added instead. One must expect that any item that is added to the stack might change.
86 lines
2.1 KiB
Go
86 lines
2.1 KiB
Go
// Copyright 2014 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 (
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"fmt"
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"math/big"
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)
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// stack is an object for basic stack operations. Items popped to the stack are
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// expected to be changed and modified. stack does not take care of adding newly
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// initialised objects.
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type stack struct {
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data []*big.Int
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}
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func newstack() *stack {
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return &stack{}
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}
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func (st *stack) Data() []*big.Int {
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return st.data
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}
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func (st *stack) push(d *big.Int) {
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// NOTE push limit (1024) is checked in baseCheck
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//stackItem := new(big.Int).Set(d)
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//st.data = append(st.data, stackItem)
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st.data = append(st.data, d)
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}
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func (st *stack) pop() (ret *big.Int) {
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ret = st.data[len(st.data)-1]
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st.data = st.data[:len(st.data)-1]
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return
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}
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func (st *stack) len() int {
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return len(st.data)
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}
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func (st *stack) swap(n int) {
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st.data[st.len()-n], st.data[st.len()-1] = st.data[st.len()-1], st.data[st.len()-n]
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}
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func (st *stack) dup(n int) {
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st.push(new(big.Int).Set(st.data[st.len()-n]))
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}
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func (st *stack) peek() *big.Int {
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return st.data[st.len()-1]
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}
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func (st *stack) require(n int) error {
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if st.len() < n {
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return fmt.Errorf("stack underflow (%d <=> %d)", len(st.data), n)
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}
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return nil
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}
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func (st *stack) Print() {
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fmt.Println("### stack ###")
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if len(st.data) > 0 {
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for i, val := range st.data {
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fmt.Printf("%-3d %v\n", i, val)
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}
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} else {
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fmt.Println("-- empty --")
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}
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fmt.Println("#############")
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}
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