github.com/arieschain/arieschain@v0.0.0-20191023063405-37c074544356/core/vm/stack.go (about)

     1  package vm
     2  
     3  import (
     4  	"fmt"
     5  	"math/big"
     6  )
     7  
     8  // stack is an object for basic stack operations. Items popped to the stack are
     9  // expected to be changed and modified. stack does not take care of adding newly
    10  // initialised objects.
    11  type Stack struct {
    12  	data []*big.Int
    13  }
    14  
    15  func newstack() *Stack {
    16  	return &Stack{data: make([]*big.Int, 0, 1024)}
    17  }
    18  
    19  func (st *Stack) Data() []*big.Int {
    20  	return st.data
    21  }
    22  
    23  func (st *Stack) push(d *big.Int) {
    24  	// NOTE push limit (1024) is checked in baseCheck
    25  	//stackItem := new(big.Int).Set(d)
    26  	//st.data = append(st.data, stackItem)
    27  	st.data = append(st.data, d)
    28  }
    29  func (st *Stack) pushN(ds ...*big.Int) {
    30  	st.data = append(st.data, ds...)
    31  }
    32  
    33  func (st *Stack) pop() (ret *big.Int) {
    34  	ret = st.data[len(st.data)-1]
    35  	st.data = st.data[:len(st.data)-1]
    36  	return
    37  }
    38  
    39  func (st *Stack) len() int {
    40  	return len(st.data)
    41  }
    42  
    43  func (st *Stack) swap(n int) {
    44  	st.data[st.len()-n], st.data[st.len()-1] = st.data[st.len()-1], st.data[st.len()-n]
    45  }
    46  
    47  func (st *Stack) dup(pool *intPool, n int) {
    48  	st.push(pool.get().Set(st.data[st.len()-n]))
    49  }
    50  
    51  func (st *Stack) peek() *big.Int {
    52  	return st.data[st.len()-1]
    53  }
    54  
    55  // Back returns the n'th item in stack
    56  func (st *Stack) Back(n int) *big.Int {
    57  	return st.data[st.len()-n-1]
    58  }
    59  
    60  func (st *Stack) require(n int) error {
    61  	if st.len() < n {
    62  		return fmt.Errorf("stack underflow (%d <=> %d)", len(st.data), n)
    63  	}
    64  	return nil
    65  }
    66  
    67  func (st *Stack) Print() {
    68  	fmt.Println("### stack ###")
    69  	if len(st.data) > 0 {
    70  		for i, val := range st.data {
    71  			fmt.Printf("%-3d  %v\n", i, val)
    72  		}
    73  	} else {
    74  		fmt.Println("-- empty --")
    75  	}
    76  	fmt.Println("#############")
    77  }