pitrix/SimpleList.h

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#ifndef SimpleList_h
#define SimpleList_h
/*
===========================================
Copyright (c) 2018 Stefan Kremser
github.com/spacehuhn
===========================================
*/
#include <type_traits>
#include <cstddef>
#include <functional>
template<class T>
struct SimpleListNode {
T data;
SimpleListNode<T>* next = NULL;
};
template<typename T>
class SimpleList {
public:
SimpleList();
SimpleList(int(*compare)(T & a, T & b));
virtual ~SimpleList();
virtual void setCompare(int (* compare)(T& a, T& b));
virtual int size();
virtual bool isSorted();
virtual bool isEmpty();
virtual void add(int index, T obj);
virtual void add(T obj);
virtual void insert(T obj);
virtual void replace(int index, T obj);
virtual void swap(int x, int y);
virtual void remove(int index);
virtual void removeFirst();
virtual void removeLast();
virtual bool has(T obj);
virtual int count(T obj);
virtual T shift();
virtual T pop();
virtual T get(int index);
virtual T getFirst();
virtual T getLast();
virtual void moveToEnd();
virtual int search(T obj);
virtual int searchNext(T obj);
virtual int binSearch(T obj);
virtual void sort();
virtual void clear();
protected:
int (* compare)(T& a, T& b) = NULL;
int listSize = 0;
SimpleListNode<T>* listBegin = NULL;
SimpleListNode<T>* listEnd = NULL;
// Helps get() method by saving last position
SimpleListNode<T>* lastNodeGot = NULL;
int lastIndexGot = -1;
bool isCached = false;
bool sorted = true;
virtual SimpleListNode<T>* getNode(int index);
virtual int binSearch(T obj, int lowerEnd, int upperEnd);
};
template<typename T>
SimpleList<T>::SimpleList() {}
template<typename T>
SimpleList<T>::SimpleList(int(*compare)(T & a, T & b)) {
setCompare(compare);
}
// Clear Nodes and free Memory
template<typename T>
SimpleList<T>::~SimpleList() {
clear();
}
template<typename T>
void SimpleList<T>::setCompare(int (* compare)(T& a, T& b)) {
this->compare = compare;
sort();
}
template<typename T>
SimpleListNode<T>* SimpleList<T>::getNode(int index) {
if ((index < 0) || (index >= listSize)) return NULL;
SimpleListNode<T>* hNode = listBegin;
int c = 0;
if (isCached && (index >= lastIndexGot)) {
c = lastIndexGot;
hNode = lastNodeGot;
}
while (hNode && c < index) {
hNode = hNode->next;
c++;
}
if (hNode) {
isCached = true;
lastIndexGot = c;
lastNodeGot = hNode;
}
return hNode;
}
template<typename T>
int SimpleList<T>::size() {
return listSize;
}
template<typename T>
bool SimpleList<T>::isSorted() {
return sorted;
}
template<typename T>
bool SimpleList<T>::isEmpty() {
return listSize == 0;
}
template<typename T>
void SimpleList<T>::add(T obj) {
// create new node
SimpleListNode<T>* newNode = new SimpleListNode<T>();
newNode->data = obj;
if (!listBegin) listBegin = newNode;
if (listEnd) {
listEnd->next = newNode;
listEnd = newNode;
} else {
listEnd = newNode;
}
listSize++;
sorted = false;
}
template<typename T>
void SimpleList<T>::add(int index, T obj) {
if ((index < 0) || (index >= listSize)) {
return;
}
SimpleListNode<T>* newNode = new SimpleListNode<T>();
newNode->data = obj;
if (index == 0) {
listBegin = newNode;
} else {
SimpleListNode<T>* nodePrev = getNode(index - 1);
newNode->next = nodePrev->next;
nodePrev->next = newNode;
}
listSize++;
sorted = false;
}
template<typename T>
void SimpleList<T>::insert(T obj) {
if (!compare) {
add(obj);
return;
}
if (!sorted) sort();
// create new node
SimpleListNode<T>* newNode = new SimpleListNode<T>();
newNode->data = obj;
if (listSize == 0) {
// add at start (first node)
listBegin = newNode;
listEnd = newNode;
} else {
if (compare(obj, listEnd->data) >= 0) {
// add at end
listEnd->next = newNode;
listEnd = newNode;
} else if (compare(obj, listBegin->data) < 0) {
// add at start
newNode->next = listBegin;
listBegin = newNode;
} else {
// insertion sort
SimpleListNode<T>* h = listBegin;
SimpleListNode<T>* p = NULL;
bool found = false;
// here a sequential search, because otherwise the previous node couldn't be accessed
while (h && !found) {
if (compare(obj, h->data) < 0) {
found = true;
} else {
p = h;
h = h->next;
}
}
newNode->next = h;
if (p) p->next = newNode;
}
}
listSize++;
}
template<typename T>
void SimpleList<T>::replace(int index, T obj) {
if ((index >= 0) && (index < listSize)) {
getNode(index)->data = obj;
}
}
template<typename T>
void SimpleList<T>::swap(int x, int y) {
// only continue when the index numbers are unequal and at least 0
if ((x != y) && (x >= 0) && (y >= 0)) {
if (x > y) { // the first index should be smaller than the second. If not, swap them!
int h = x;
x = y;
y = h;
}
// When data is small, copy it
if (sizeof(T) < 24) {
SimpleListNode<T>* nodeA = getNode(x);
SimpleListNode<T>* nodeB = getNode(y);
T h = nodeA->data;
nodeA->data = nodeB->data;
nodeB->data = h;
}
// otherwise change the pointers
else {
// Example: a -> b -> c -> ... -> g -> h -> i
// we want to swap b with h
SimpleListNode<T>* nodeA = getNode(x - 1); // x.prev
SimpleListNode<T>* nodeB = getNode(x); // x
SimpleListNode<T>* nodeC = getNode(x + 1); // x.next
SimpleListNode<T>* nodeG = y - 1 == x ? nodeB : getNode(y - 1); // y.prev
SimpleListNode<T>* nodeH = getNode(y); // y
SimpleListNode<T>* nodeI = getNode(y + 1); // y.next
// a -> h -> i b -> c -> ... -> g -> h -> i
if (nodeA) nodeA->next = nodeH;
else listBegin = nodeH;
// a -> h -> c -> ... -> g -> h -> i b -> i
if (nodeH != nodeC) // when nodes between b and h exist
nodeH->next = nodeC;
else nodeH->next = nodeB;
// a -> h -> i b -> i
nodeB->next = nodeI;
if (!nodeI) listEnd = nodeB;
// a -> h -> c -> ... -> g -> b -> i
if (nodeG != nodeB) // when more than 1 nodes between b and h exist
nodeG->next = nodeB;
}
}
}
template<typename T>
void SimpleList<T>::remove(int index) {
if ((index < 0) || (index >= listSize)) return;
SimpleListNode<T>* nodePrev = getNode(index - 1);
SimpleListNode<T>* nodeToDelete = getNode(index);
if (index == 0) {
listBegin = nodeToDelete->next;
} else {
nodePrev->next = nodeToDelete->next;
if (!nodePrev->next) listEnd = nodePrev;
}
delete nodeToDelete;
isCached = false;
listSize--;
}
template<typename T>
void SimpleList<T>::removeFirst() {
remove(0);
}
template<typename T>
void SimpleList<T>::removeLast() {
remove(listSize - 1);
}
template<typename T>
bool SimpleList<T>::has(T obj) {
return binSearch(obj) >= 0;
}
template<typename T>
int SimpleList<T>::count(T obj) {
if (compare == NULL) return -1;
int c = 0;
for (int i = 0; i < listSize; i++) {
if (compare(obj, getNode(i)->data) == 0) c++;
}
return c;
}
template<typename T>
T SimpleList<T>::get(int index) {
SimpleListNode<T>* h = getNode(index);
if (h) return h->data;
return T();
}
template<typename T>
T SimpleList<T>::getFirst() {
return get(0);
}
template<typename T>
T SimpleList<T>::getLast() {
return get(listSize - 1);
}
template<typename T>
void SimpleList<T>::moveToEnd() {
SimpleListNode<T>* h = listBegin;
if (!h) return;
listBegin = listBegin->next;
listEnd->next = h;
h->next = NULL;
listEnd = h;
lastNodeGot = NULL;
lastIndexGot = -1;
isCached = false;
sorted = false;
}
template<typename T>
int SimpleList<T>::search(T obj) {
if (compare == NULL) return -1;
int i = 0;
SimpleListNode<T>* hNode = getNode(i);
bool found = compare(obj, hNode->data) == 0;
while (!found && i < listSize) {
i++;
hNode = getNode(i);
found = compare(obj, hNode->data) == 0;
}
return found ? i : -1;
}
template<typename T>
int SimpleList<T>::searchNext(T obj) {
if (compare == NULL) return -1;
int i = lastIndexGot;
SimpleListNode<T>* hNode = lastNodeGot;
bool found = compare(obj, hNode->data) == 0;
while (!found && i < listSize) {
i++;
hNode = getNode(i);
found = compare(obj, hNode->data) == 0;
}
return found ? i : -1;
}
template<typename T>
int SimpleList<T>::binSearch(T obj, int lowerEnd, int upperEnd) {
if (!compare || !sorted) return search(obj);
if (!listBegin) return -1;
int res;
int mid = (lowerEnd + upperEnd) / 2;
SimpleListNode<T>* hNode = getNode(0);
int hIndex = 0;
while (lowerEnd <= upperEnd) {
hNode = lastNodeGot;
hIndex = lastIndexGot;
res = compare(obj, getNode(mid)->data);
if (res == 0) {
return mid;
} else if (res < 0) {
// when going left, set cached node back to previous cached node
lastNodeGot = hNode;
lastIndexGot = hIndex;
isCached = true;
upperEnd = mid - 1;
mid = (lowerEnd + upperEnd) / 2;
} else if (res > 0) {
lowerEnd = mid + 1;
mid = (lowerEnd + upperEnd) / 2;
}
}
return -1;
}
template<typename T>
int SimpleList<T>::binSearch(T obj) {
return binSearch(obj, 0, listSize - 1);
}
template<typename T>
T SimpleList<T>::pop() {
T data = getLast();
removeLast();
return data;
}
template<typename T>
T SimpleList<T>::shift() {
T data = getFirst();
removeFirst();
return data;
}
template<typename T>
void SimpleList<T>::clear() {
while (listSize > 0) removeFirst();
listSize = 0;
listBegin = NULL;
listEnd = NULL;
lastNodeGot = NULL;
lastIndexGot = -1;
isCached = false;
sorted = true;
}
template<typename T>
void SimpleList<T>::sort() {
if (compare == NULL) return;
// selection sort (less swaps than insertion sort)
int indexH; // index of node i
int indexMin; // index of next minimum node
SimpleListNode<T>* nodeMin; // next minimum node
SimpleListNode<T>* nodeH; // helper node at index j
for (int i = 0; i < listSize - 1; i++) {
nodeMin = getNode(i);
indexH = i;
indexMin = i;
for (int j = i + 1; j < listSize; j++) {
nodeH = getNode(j);
if (compare(nodeMin->data, nodeH->data) > 0) {
nodeMin = nodeH;
indexMin = j;
}
}
swap(indexH, indexMin);
}
this->sorted = true;
}
#endif // ifndef SimpleList_h