123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100 |
- // Copyright 2014 The go-ethereum Authors
- // This file is part of the go-ethereum library.
- //
- // The go-ethereum 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 go-ethereum 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 go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
- package vm
- import (
- "fmt"
- "sync"
- "github.com/holiman/uint256"
- )
- var stackPool = sync.Pool{
- New: func() interface{} {
- return &Stack{data: make([]uint256.Int, 0, 16)}
- },
- }
- // Stack is an object for basic stack operations. Items popped to the stack are
- // expected to be changed and modified. stack does not take care of adding newly
- // initialised objects.
- type Stack struct {
- data []uint256.Int
- }
- func newstack() *Stack {
- return stackPool.Get().(*Stack)
- }
- func returnStack(s *Stack) {
- s.data = s.data[:0]
- stackPool.Put(s)
- }
- // Data returns the underlying uint256.Int array.
- func (st *Stack) Data() []uint256.Int {
- return st.data
- }
- func (st *Stack) push(d *uint256.Int) {
- // NOTE push limit (1024) is checked in baseCheck
- st.data = append(st.data, *d)
- }
- func (st *Stack) pushN(ds ...uint256.Int) {
- // FIXME: Is there a way to pass args by pointers.
- st.data = append(st.data, ds...)
- }
- func (st *Stack) pop() (ret uint256.Int) {
- ret = st.data[len(st.data)-1]
- st.data = st.data[:len(st.data)-1]
- return
- }
- func (st *Stack) len() int {
- return len(st.data)
- }
- func (st *Stack) swap(n int) {
- st.data[st.len()-n], st.data[st.len()-1] = st.data[st.len()-1], st.data[st.len()-n]
- }
- func (st *Stack) dup(n int) {
- st.push(&st.data[st.len()-n])
- }
- func (st *Stack) peek() *uint256.Int {
- return &st.data[st.len()-1]
- }
- // Back returns the n'th item in stack
- func (st *Stack) Back(n int) *uint256.Int {
- return &st.data[st.len()-n-1]
- }
- // Print dumps the content of the stack
- func (st *Stack) Print() {
- fmt.Println("### stack ###")
- if len(st.data) > 0 {
- for i, val := range st.data {
- fmt.Printf("%-3d %v\n", i, val)
- }
- } else {
- fmt.Println("-- empty --")
- }
- fmt.Println("#############")
- }
|