plugeth/core/vm/stack.go

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// Copyright 2014 The go-ethereum Authors
// This file is part of the go-ethereum library.
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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
// 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,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// 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/>.
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package vm
import (
"fmt"
"math/big"
)
// 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 {
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data []*big.Int
}
func newstack() *stack {
return &stack{}
}
func (st *stack) Data() []*big.Int {
return st.data
}
func (st *stack) push(d *big.Int) {
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// NOTE push limit (1024) is checked in baseCheck
//stackItem := new(big.Int).Set(d)
//st.data = append(st.data, stackItem)
st.data = append(st.data, d)
}
func (st *stack) pushN(ds ...*big.Int) {
st.data = append(st.data, ds...)
}
func (st *stack) pop() (ret *big.Int) {
ret = st.data[len(st.data)-1]
st.data = st.data[:len(st.data)-1]
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return
}
func (st *stack) len() int {
return len(st.data)
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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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}
func (st *stack) dup(n int) {
st.push(new(big.Int).Set(st.data[st.len()-n]))
}
func (st *stack) peek() *big.Int {
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return st.data[st.len()-1]
}
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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return nil
}
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("#############")
}