gitlab.com/flarenetwork/coreth@v0.1.1/core/vm/stack.go (about)

     1  // (c) 2019-2020, Ava Labs, Inc.
     2  //
     3  // This file is a derived work, based on the go-ethereum library whose original
     4  // notices appear below.
     5  //
     6  // It is distributed under a license compatible with the licensing terms of the
     7  // original code from which it is derived.
     8  //
     9  // Much love to the original authors for their work.
    10  // **********
    11  // Copyright 2014 The go-ethereum Authors
    12  // This file is part of the go-ethereum library.
    13  //
    14  // The go-ethereum library is free software: you can redistribute it and/or modify
    15  // it under the terms of the GNU Lesser General Public License as published by
    16  // the Free Software Foundation, either version 3 of the License, or
    17  // (at your option) any later version.
    18  //
    19  // The go-ethereum library is distributed in the hope that it will be useful,
    20  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    21  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    22  // GNU Lesser General Public License for more details.
    23  //
    24  // You should have received a copy of the GNU Lesser General Public License
    25  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    26  
    27  package vm
    28  
    29  import (
    30  	"fmt"
    31  	"sync"
    32  
    33  	"github.com/holiman/uint256"
    34  )
    35  
    36  var stackPool = sync.Pool{
    37  	New: func() interface{} {
    38  		return &Stack{data: make([]uint256.Int, 0, 16)}
    39  	},
    40  }
    41  
    42  // Stack is an object for basic stack operations. Items popped to the stack are
    43  // expected to be changed and modified. stack does not take care of adding newly
    44  // initialised objects.
    45  type Stack struct {
    46  	data []uint256.Int
    47  }
    48  
    49  func newstack() *Stack {
    50  	return stackPool.Get().(*Stack)
    51  }
    52  
    53  func returnStack(s *Stack) {
    54  	s.data = s.data[:0]
    55  	stackPool.Put(s)
    56  }
    57  
    58  // Data returns the underlying uint256.Int array.
    59  func (st *Stack) Data() []uint256.Int {
    60  	return st.data
    61  }
    62  
    63  func (st *Stack) push(d *uint256.Int) {
    64  	// NOTE push limit (1024) is checked in baseCheck
    65  	st.data = append(st.data, *d)
    66  }
    67  func (st *Stack) pushN(ds ...uint256.Int) {
    68  	// FIXME: Is there a way to pass args by pointers.
    69  	st.data = append(st.data, ds...)
    70  }
    71  
    72  func (st *Stack) pop() (ret uint256.Int) {
    73  	ret = st.data[len(st.data)-1]
    74  	st.data = st.data[:len(st.data)-1]
    75  	return
    76  }
    77  
    78  func (st *Stack) len() int {
    79  	return len(st.data)
    80  }
    81  
    82  func (st *Stack) swap(n int) {
    83  	st.data[st.len()-n], st.data[st.len()-1] = st.data[st.len()-1], st.data[st.len()-n]
    84  }
    85  
    86  func (st *Stack) dup(n int) {
    87  	st.push(&st.data[st.len()-n])
    88  }
    89  
    90  func (st *Stack) peek() *uint256.Int {
    91  	return &st.data[st.len()-1]
    92  }
    93  
    94  // Back returns the n'th item in stack
    95  func (st *Stack) Back(n int) *uint256.Int {
    96  	return &st.data[st.len()-n-1]
    97  }
    98  
    99  // Print dumps the content of the stack
   100  func (st *Stack) Print() {
   101  	fmt.Println("### stack ###")
   102  	if len(st.data) > 0 {
   103  		for i, val := range st.data {
   104  			fmt.Printf("%-3d  %v\n", i, val)
   105  		}
   106  	} else {
   107  		fmt.Println("-- empty --")
   108  	}
   109  	fmt.Println("#############")
   110  }