mirror of
https://github.com/emirpasic/gods
synced 2024-11-16 12:12:59 +00:00
92 lines
2.5 KiB
Go
92 lines
2.5 KiB
Go
// Copyright (c) 2015, Emir Pasic. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
// Package arraystack implements a stack backed by array list.
|
|
//
|
|
// Structure is not thread safe.
|
|
//
|
|
// Reference: https://en.wikipedia.org/wiki/Stack_%28abstract_data_type%29#Array
|
|
package arraystack
|
|
|
|
import (
|
|
"fmt"
|
|
"github.com/emirpasic/gods/lists/arraylist"
|
|
"github.com/emirpasic/gods/stacks"
|
|
"strings"
|
|
)
|
|
|
|
func assertStackImplementation() {
|
|
var _ stacks.Stack = (*Stack)(nil)
|
|
}
|
|
|
|
// Stack holds elements in an array-list
|
|
type Stack struct {
|
|
list *arraylist.List
|
|
}
|
|
|
|
// New instantiates a new empty stack
|
|
func New() *Stack {
|
|
return &Stack{list: arraylist.New()}
|
|
}
|
|
|
|
// Push adds a value onto the top of the stack
|
|
func (stack *Stack) Push(value interface{}) {
|
|
stack.list.Add(value)
|
|
}
|
|
|
|
// Pop removes top element on stack and returns it, or nil if stack is empty.
|
|
// Second return parameter is true, unless the stack was empty and there was nothing to pop.
|
|
func (stack *Stack) Pop() (value interface{}, ok bool) {
|
|
value, ok = stack.list.Get(stack.list.Size() - 1)
|
|
stack.list.Remove(stack.list.Size() - 1)
|
|
return
|
|
}
|
|
|
|
// Peek returns top element on the stack without removing it, or nil if stack is empty.
|
|
// Second return parameter is true, unless the stack was empty and there was nothing to peek.
|
|
func (stack *Stack) Peek() (value interface{}, ok bool) {
|
|
return stack.list.Get(stack.list.Size() - 1)
|
|
}
|
|
|
|
// Empty returns true if stack does not contain any elements.
|
|
func (stack *Stack) Empty() bool {
|
|
return stack.list.Empty()
|
|
}
|
|
|
|
// Size returns number of elements within the stack.
|
|
func (stack *Stack) Size() int {
|
|
return stack.list.Size()
|
|
}
|
|
|
|
// Clear removes all elements from the stack.
|
|
func (stack *Stack) Clear() {
|
|
stack.list.Clear()
|
|
}
|
|
|
|
// Values returns all elements in the stack (LIFO order).
|
|
func (stack *Stack) Values() []interface{} {
|
|
size := stack.list.Size()
|
|
elements := make([]interface{}, size, size)
|
|
for i := 1; i <= size; i++ {
|
|
elements[size-i], _ = stack.list.Get(i - 1) // in reverse (LIFO)
|
|
}
|
|
return elements
|
|
}
|
|
|
|
// String returns a string representation of container
|
|
func (stack *Stack) String() string {
|
|
str := "ArrayStack\n"
|
|
values := []string{}
|
|
for _, value := range stack.list.Values() {
|
|
values = append(values, fmt.Sprintf("%v", value))
|
|
}
|
|
str += strings.Join(values, ", ")
|
|
return str
|
|
}
|
|
|
|
// Check that the index is within bounds of the list
|
|
func (stack *Stack) withinRange(index int) bool {
|
|
return index >= 0 && index < stack.list.Size()
|
|
}
|