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// 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("#############")
}
var rStackPool = sync.Pool{
New: func() interface{} {
return &ReturnStack{data: make([]uint32, 0, 10)}
},
}
// ReturnStack is an object for basic return stack operations.
type ReturnStack struct {
data []uint32
}
func newReturnStack() *ReturnStack {
return rStackPool.Get().(*ReturnStack)
}
func returnRStack(rs *ReturnStack) {
rs.data = rs.data[:0]
rStackPool.Put(rs)
}
func (st *ReturnStack) push(d uint32) {
st.data = append(st.data, d)
}
// A uint32 is sufficient as for code below 4.2G
func (st *ReturnStack) pop() (ret uint32) {
ret = st.data[len(st.data)-1]
st.data = st.data[:len(st.data)-1]
return
}