github.com/ontio/ontology@v1.14.4/vm/evm/stack.go (about)

     1  // Copyright (C) 2021 The Ontology Authors
     2  // Copyright 2014 The go-ethereum Authors
     3  // This file is part of the go-ethereum library.
     4  //
     5  // The go-ethereum library is free software: you can redistribute it and/or modify
     6  // it under the terms of the GNU Lesser General Public License as published by
     7  // the Free Software Foundation, either version 3 of the License, or
     8  // (at your option) any later version.
     9  //
    10  // The go-ethereum library is distributed in the hope that it will be useful,
    11  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    12  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    13  // GNU Lesser General Public License for more details.
    14  //
    15  // You should have received a copy of the GNU Lesser General Public License
    16  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    17  
    18  package evm
    19  
    20  import (
    21  	"fmt"
    22  	"sync"
    23  
    24  	"github.com/holiman/uint256"
    25  )
    26  
    27  var stackPool = sync.Pool{
    28  	New: func() interface{} {
    29  		return &Stack{data: make([]uint256.Int, 0, 16)}
    30  	},
    31  }
    32  
    33  // Stack is an object for basic stack operations. Items popped to the stack are
    34  // expected to be changed and modified. stack does not take care of adding newly
    35  // initialised objects.
    36  type Stack struct {
    37  	data []uint256.Int
    38  }
    39  
    40  func newstack() *Stack {
    41  	return stackPool.Get().(*Stack)
    42  }
    43  
    44  func returnStack(s *Stack) {
    45  	s.data = s.data[:0]
    46  	stackPool.Put(s)
    47  }
    48  
    49  // Data returns the underlying uint256.Int array.
    50  func (st *Stack) Data() []uint256.Int {
    51  	return st.data
    52  }
    53  
    54  func (st *Stack) push(d *uint256.Int) {
    55  	// NOTE push limit (1024) is checked in baseCheck
    56  	st.data = append(st.data, *d)
    57  }
    58  func (st *Stack) pushN(ds ...uint256.Int) {
    59  	// FIXME: Is there a way to pass args by pointers.
    60  	st.data = append(st.data, ds...)
    61  }
    62  
    63  func (st *Stack) pop() (ret uint256.Int) {
    64  	ret = st.data[len(st.data)-1]
    65  	st.data = st.data[:len(st.data)-1]
    66  	return
    67  }
    68  
    69  func (st *Stack) len() int {
    70  	return len(st.data)
    71  }
    72  
    73  func (st *Stack) swap(n int) {
    74  	st.data[st.len()-n], st.data[st.len()-1] = st.data[st.len()-1], st.data[st.len()-n]
    75  }
    76  
    77  func (st *Stack) dup(n int) {
    78  	st.push(&st.data[st.len()-n])
    79  }
    80  
    81  func (st *Stack) peek() *uint256.Int {
    82  	return &st.data[st.len()-1]
    83  }
    84  
    85  // Back returns the n'th item in stack
    86  func (st *Stack) Back(n int) *uint256.Int {
    87  	return &st.data[st.len()-n-1]
    88  }
    89  
    90  // Print dumps the content of the stack
    91  func (st *Stack) Print() {
    92  	fmt.Println("### stack ###")
    93  	if len(st.data) > 0 {
    94  		for i, val := range st.data {
    95  			fmt.Printf("%-3d  %v\n", i, val)
    96  		}
    97  	} else {
    98  		fmt.Println("-- empty --")
    99  	}
   100  	fmt.Println("#############")
   101  }
   102  
   103  var rStackPool = sync.Pool{
   104  	New: func() interface{} {
   105  		return &ReturnStack{data: make([]uint32, 0, 10)}
   106  	},
   107  }
   108  
   109  // ReturnStack is an object for basic return stack operations.
   110  type ReturnStack struct {
   111  	data []uint32
   112  }
   113  
   114  func newReturnStack() *ReturnStack {
   115  	return rStackPool.Get().(*ReturnStack)
   116  }
   117  
   118  func returnRStack(rs *ReturnStack) {
   119  	rs.data = rs.data[:0]
   120  	rStackPool.Put(rs)
   121  }
   122  
   123  func (st *ReturnStack) push(d uint32) {
   124  	st.data = append(st.data, d)
   125  }
   126  
   127  // A uint32 is sufficient as for code below 4.2G
   128  func (st *ReturnStack) pop() (ret uint32) {
   129  	ret = st.data[len(st.data)-1]
   130  	st.data = st.data[:len(st.data)-1]
   131  	return
   132  }