Implemented priority queue in C; removed C++ heap
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@@ -52,4 +52,4 @@ int insert(struct priority_queue_t *queue, struct process_t *process);
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* @param process
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* @return int
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*/
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int remove(struct priority_queue_t *queue, struct process_t *process);
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int remove(struct priority_queue_t *queue, struct process_t *process);
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98
src/heap.hpp
98
src/heap.hpp
@@ -1,98 +0,0 @@
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#ifndef SCHEDULER_H
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#define SCHEDULER_H
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#include <stddef.h>
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#include "process.hpp"
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namespace kernelns
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{
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template<class T>
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class Heap
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{
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public:
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Heap()
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{
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}
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Heap(T** array, size_t maxSize)
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{
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m_array = array;
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m_size = 0;
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m_limit = maxSize;
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}
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T* extractMin()
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{
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if(m_size == 0)
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return nullptr;
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m_size--;
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T* p = m_array[0];
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m_array[0] = m_array[m_size];
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heapify(0);
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return p;
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}
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Status insert(T* n)
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{
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if(m_size == m_limit)
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return Status::NoMemory;
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size_t i = m_size;
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m_size++;
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while(i > 0 && *m_array[(i - 1) / 2] > *n)
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{
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m_array[i] = m_array[(i - 1) / 2];
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i = (i - 1) / 2;
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}
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m_array[i] = n;
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return Status::OK;
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}
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void remove(T* n)
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{
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for(size_t i = 0; i < m_size; i++)
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{
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if(m_array[i] == n)
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{
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m_size--;
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m_array[i] = m_array[m_size];
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heapify(i);
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break;
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}
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}
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}
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private:
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void heapify(size_t index)
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{
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if(i * 2 + 1 >= m_size)
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return;
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if (*m_array[i * 2 + 1] <= *m_array[i] && *m_array[i * 2 + 1] <= *m_array[i * 2 + 2])
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{
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T buffer = m_array[i];
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m_array[i] = m_array[i * 2 + 1];
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m_array[i * 2 + 1] = buffer;
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heapify(i * 2 + 1);
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}
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else if (*m_array[i * 2 + 2] <= *m_array[i] && *m_array[i * 2 + 2] <= *m_array[i * 2 + 1])
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{
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T buffer = m_array[i];
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m_array[i] = m_array[i * 2 + 2];
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m_array[i * 2 + 2] = buffer;
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heapify(i * 2 + 2);
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}
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}
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T** m_array;
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size_t m_size, m_limit;
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};
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};
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#endif
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67
src/priorityqueue.c
Normal file
67
src/priorityqueue.c
Normal file
@@ -0,0 +1,67 @@
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#include "priorityqueue.h"
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#include "types/status.h"
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void heapify(struct priority_queue_t *queue, size_t i)
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{
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if(i * 2 + 1 >= queue->size)
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{
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return;
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}
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else if(queue->heap[i * 2 + 1]->priority <= queue->heap[i]->priority
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&& queue->heap[i * 2 + 1]->priority <= queue->heap[i * 2 + 2]->priority)
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{
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struct process_t *buffer = queue->heap[i];
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queue->heap[i] = queue->heap[i * 2 + 1];
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queue->heap[i * 2 + 1] = buffer;
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heapify(queue, i * 2 + 1);
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}
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else if(queue->heap[i * 2 + 2]->priority <= queue->heap[i]->priority
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&& queue->heap[i * 2 + 2]->priority <= queue->heap[i * 2 + 1]->priority)
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{
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struct process_t *buffer = queue->heap[i];
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queue->heap[i] = queue->heap[i * 2 + 2];
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queue->heap[i * 2 + 2] = buffer;
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heapify(queue, i * 2 + 2);
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}
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}
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struct process_t *extract_min(struct priority_queue_t *queue)
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{
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if(queue->size == 0)
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return NULL;
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queue->size--;
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struct process_t *p = queue->heap[0];
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queue->heap[0] = queue->heap[queue->size];
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heapify(queue, 0);
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return p;
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}
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int insert(struct priority_queue_t *queue, struct process_t *process)
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{
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if(queue->size == queue->capacity)
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return S_OUT_OF_MEMORY;
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size_t i = queue->size;
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queue->size++;
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while(i > 0 && queue->heap[(i - 1) / 2]->priority > process->priority)
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{
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queue->heap[i] = queue->heap[(i - 1) / 2];
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i = (i - 1) / 2;
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}
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queue->heap[i] = process;
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return S_OK;
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}
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int remove(struct priority_queue_t *queue, struct process_t *process)
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{
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for(size_t i = 0; i < queue->size; i++)
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{
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if(queue->heap[i] == process)
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{
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queue->size--;
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queue->heap[i] = queue->heap[queue->size];
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heapify(queue, i);
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return S_OK;
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}
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}
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return S_OUT_OF_BOUNDS;
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}
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