mirror of
https://github.com/emirpasic/gods
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61 lines
2.0 KiB
Go
61 lines
2.0 KiB
Go
// Copyright (c) 2015, Emir Pasic. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package linkedliststack
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import "github.com/emirpasic/gods/containers"
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func assertIteratorImplementation() {
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var _ containers.IteratorWithIndex = (*Iterator)(nil)
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}
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// Iterator returns a stateful iterator whose values can be fetched by an index.
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type Iterator struct {
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stack *Stack
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index int
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}
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// Iterator returns a stateful iterator whose values can be fetched by an index.
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func (stack *Stack) Iterator() Iterator {
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return Iterator{stack: stack, index: -1}
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}
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// Next moves the iterator to the next element and returns true if there was a next element in the container.
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// If Next() returns true, then next element's index and value can be retrieved by Index() and Value().
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// If Next() was called for the first time, then it will point the iterator to the first element if it exists.
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// Modifies the state of the iterator.
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func (iterator *Iterator) Next() bool {
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if iterator.index < iterator.stack.Size() {
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iterator.index++
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}
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return iterator.stack.withinRange(iterator.index)
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}
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// Value returns the current element's value.
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// Does not modify the state of the iterator.
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func (iterator *Iterator) Value() interface{} {
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value, _ := iterator.stack.list.Get(iterator.index) // in reverse (LIFO)
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return value
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}
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// Index returns the current element's index.
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// Does not modify the state of the iterator.
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func (iterator *Iterator) Index() int {
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return iterator.index
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}
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// Begin resets the iterator to its initial state (one-before-first)
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// Call Next() to fetch the first element if any.
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func (iterator *Iterator) Begin() {
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iterator.index = -1
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}
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// First moves the iterator to the first element and returns true if there was a first element in the container.
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// If First() returns true, then first element's index and value can be retrieved by Index() and Value().
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// Modifies the state of the iterator.
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func (iterator *Iterator) First() bool {
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iterator.Begin()
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return iterator.Next()
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}
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