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gods/maps/treebidimap/iterator.go

105 lines
3.8 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 treebidimap
import (
"github.com/emirpasic/gods/containers"
rbt "github.com/emirpasic/gods/trees/redblacktree"
)
// Assert Iterator implementation
var _ containers.ReverseIteratorWithKey = (*Iterator)(nil)
// Iterator holding the iterator's state
type Iterator struct {
iterator rbt.Iterator
}
// Iterator returns a stateful iterator whose elements are key/value pairs.
func (m *Map) Iterator() Iterator {
return Iterator{iterator: m.forwardMap.Iterator()}
}
// Next moves the iterator to the next element and returns true if there was a next element in the container.
// If Next() returns true, then next element's key and value can be retrieved by Key() and Value().
// If Next() was called for the first time, then it will point the iterator to the first element if it exists.
// Modifies the state of the iterator.
func (iterator *Iterator) Next() bool {
return iterator.iterator.Next()
}
// Prev moves the iterator to the previous element and returns true if there was a previous element in the container.
// If Prev() returns true, then previous element's key and value can be retrieved by Key() and Value().
// Modifies the state of the iterator.
func (iterator *Iterator) Prev() bool {
return iterator.iterator.Prev()
}
// Value returns the current element's value.
// Does not modify the state of the iterator.
func (iterator *Iterator) Value() interface{} {
return iterator.iterator.Value().(*data).value
}
// Key returns the current element's key.
// Does not modify the state of the iterator.
func (iterator *Iterator) Key() interface{} {
return iterator.iterator.Key()
}
// Begin resets the iterator to its initial state (one-before-first)
// Call Next() to fetch the first element if any.
func (iterator *Iterator) Begin() {
iterator.iterator.Begin()
}
// End moves the iterator past the last element (one-past-the-end).
// Call Prev() to fetch the last element if any.
func (iterator *Iterator) End() {
iterator.iterator.End()
}
// First moves the iterator to the first element and returns true if there was a first element in the container.
// If First() returns true, then first element's key and value can be retrieved by Key() and Value().
// Modifies the state of the iterator
func (iterator *Iterator) First() bool {
return iterator.iterator.First()
}
// Last moves the iterator to the last element and returns true if there was a last element in the container.
// If Last() returns true, then last element's key and value can be retrieved by Key() and Value().
// Modifies the state of the iterator.
func (iterator *Iterator) Last() bool {
return iterator.iterator.Last()
}
// NextTo moves the iterator to the next element from current position that satisfies the condition given by the
// passed function, and returns true if there was a next element in the container.
// If NextTo() returns true, then next element's key and value can be retrieved by Key() and Value().
// Modifies the state of the iterator.
func (iterator *Iterator) NextTo(f func(key interface{}, value interface{}) bool) bool {
for iterator.Next() {
key, value := iterator.Key(), iterator.Value()
if f(key, value) {
return true
}
}
return false
}
// PrevTo moves the iterator to the previous element from current position that satisfies the condition given by the
// passed function, and returns true if there was a next element in the container.
// If PrevTo() returns true, then next element's key and value can be retrieved by Key() and Value().
// Modifies the state of the iterator.
func (iterator *Iterator) PrevTo(f func(key interface{}, value interface{}) bool) bool {
for iterator.Prev() {
key, value := iterator.Key(), iterator.Value()
if f(key, value) {
return true
}
}
return false
}