LinkedList

| CHANGELOG |

This is a fork of ivanseidel's LinkedList lib. I needed some features for my projects but it looks like upstream is not suported much recently. So I decided to make some improvements and merge fixes on my owm. At least till ivanseidel's PR's are pending.

Changes compared to origin

• more optimization and improvement could be found in CHANGELOG

• provide LinkedList object deep-copy via assign operator

• Lib could be build as an ESP-IDF component via provided CMakeLists.txt

• getters methods are const-aware correct

• STL-like forward Iterators added

• Cache node improvement

• added head()/tail()/exist() helpers to make user code simple on Node access/checks

• added wrapper namespace to workaround Async Webserver Class name collision

• updated library.json for PlatformIO capability

• merged ivanseidel/LinkedList#48 (moved test.cpp into subdir)

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This library was developed targeting Arduino applications. However, works just great with any C++.

Implementing a buffer for objects takes time. If we are not in the mood, we just create an array[1000] with enough size.

The objective of this library is to create a pattern for projects. If you need to use a List of: int, float, objects, Lists or Wales. This is what you are looking for.

With a simple but powerful caching algorithm, you can get subsequent objects much faster than usual. Tested without any problems with Lists bigger than 2000 members.

Installation

1. Download the Latest release from gitHub.
2. Unzip and modify the Folder name to "LinkedList" (Remove the '-version')
3. Paste the modified folder on your Library folder (On your Libraries folder inside Sketchbooks or Arduino software).
4. Reopen the Arduino software.

If you are here, because another Library requires this class, just don't waste time reading bellow. Install and ready.

Tests

cd extras/test to this directory and run g++ -std=c++14 extras/test/tests.cpp -o tests && ./tests

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Getting started

The LinkedList class

In case you don't know what a LinkedList is and what it's used for, take a quick look at Wikipedia::LinkedList before continuing.

To declare a LinkedList object

// Instantiate a LinkedList that will hold 'integer'
LinkedList<int> myLinkedList = LinkedList<int>();

// Or just this
LinkedList<int> myLinkedList;

// But if you are instantiating a pointer LinkedList...
LinkedList<int> *myLinkedList = new LinkedList<int>();

// If you want a LinkedList with any other type such as 'MyClass'
// Make sure you call delete(MyClass) when you remove!
LinkedList<MyClass> *myLinkedList = new LinkedList<MyClass>();

Getting the size of the linked list

// To get the size of a linked list, make use of the size() method
int theSize = myList.size();

// Notice that if it's pointer to the linked list, you should use -> instead
int theSize = myList->size();

Adding elements

// add(obj) method will insert at the END of the list
myList.add(myObject);

// add(index, obj) method will try to insert the object at the specified index
myList.add(0, myObject); // Add at the beginning
myList.add(3, myObject); // Add at index 3

// unshift(obj) method will insert the object at the beginning
myList.unshift(myObject);

Getting elements

// get(index) will return the element at index
// (notice that the start element is 0, not 1)

// Get the FIRST element
myObject = myList.get(0);
or
myObject = myList.head();


// Get the third element
myObject = myList.get(2);

// Get the LAST element
myObject = myList.get(myList.size() - 1);
or
myObject = myList.tail();

Changing elements

// set(index, obj) method will change the object at index to obj

// Change the first element to myObject
myList.set(0, myObject);

// Change the third element to myObject
myList.set(2, myObject);

// Change the LAST element of the list
myList.set(myList.size() - 1, myObject);

Deleting elements

NOTE: Deleting list nodes won't DELETE/FREE memory from Pointers, if you are storing Classes/Poiners in a list, manualy delete and free those before removing nodes. OR better to use std::shared_pointer or other smart structures.

// remove(index) will remove and return the element at index

// Unlink/delete the first object
myList.unlink(0);

// Get and Delete the third element
myDeletedObject = myList.remove(2);

// pop() will remove and return the LAST element
myDeletedObject = myList.pop();

// shift() will remove and return the FIRST element
myDeletedObject = myList.shift();

// clear() will erase the entire list, leaving it with 0 elements
myList.clear();

Sorting elements

// Sort using a comparator function
myList.sort(myComparator);

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Library Reference

ListNode struct

• T ListNode::data - The object data

• ListNode<T> *next - Pointer to the next Node

LinkedList class

boolean methods returns if succeeded

• LinkedList<T>::LinkedList() - Constructor.

• LinkedList<T>::~LinkedList() - Destructor. Clear Nodes to minimize memory. Does not free pointer memory.

• int LinkedList<T>::size() - Returns the current size of the list.

• bool LinkedList<T>::add(T) - Add element T at the END of the list.

• bool LinkedList<T>::add(int index, T) - Add element T at index of the list.

• bool LinkedList<T>::unshift(T) - Add element T at the BEGINNING of the list.

• bool LinkedList<T>::set(int index, T) - Set the element at index to T.

• T LinkedList<T>::remove(int index) - Remove element at index. Return the removed element. Does not free pointer memory

• T LinkedList<T>::pop() - Remove the LAST element. Return the removed element.

• T LinkedList<T>::shift() - Remove the FIRST element. Return the removed element.

• T LinkedList<T>::get(int index) - Return the element at index.

• void LinkedList<T>::clear() - Removes all elements. Does not free pointer memory.

• void LinkedList<T>::sort(int (*cmp)(T &, T &)) - Sorts the linked list according to a comparator funcrion. The comparator should return < 0 if the first argument should be sorted before the second, and > 0 if the first argument should be sorted after the first element. (Same as how strcmp() works.)

• protected int LinkedList<T>::_size - Holds the cached size of the list.

• protected ListNode<T> LinkedList<T>::*root - Holds the root node of the list.

• protected ListNode<T> LinkedList<T>::*last - Holds the last node of the list.

• protected ListNode<T>* LinkedList<T>::getNode(int index) - Returns the index node of the list.

Version History

• 1.1 (2013-07-20): Cache implemented. Getting subsequent objects is now O(N). Before, O(N^2).
• 1.0 (2013-07-20): Original release