Diff: Queue.h

Revision:

2:6c45738bba43

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Queue.h	Mon Jul 24 09:36:09 2017 +0000
@@ -0,0 +1,126 @@
+// downloaded from: https://gist.github.com/ArnonEilat/4471278
+
+#include <stdlib.h>
+#include <stdio.h>
+
+#define TRUE  1
+#define FALSE   0
+#define QUEUE_STRING_LENGTH 40
+
+/* a link in the queue, holds the info and point to the next Node*/
+typedef struct {
+    int length;
+    char payload[QUEUE_STRING_LENGTH-1];  // null-terminated string, max 256 characters long, this may be JSON or any other format, depending on the application
+} DATA;
+
+typedef struct Node_t {
+    DATA data;
+    struct Node_t *prev;
+} NODE;
+
+/* the HEAD of the Queue, hold the amount of node's that are in the queue*/
+typedef struct Queue {
+    NODE *head;
+    NODE *tail;
+    int size;
+    int limit;
+} Queue;
+
+Queue *ConstructQueue(int limit);
+void DestructQueue(Queue *queue);
+int Enqueue(Queue *pQueue, NODE *item);
+NODE *Dequeue(Queue *pQueue);
+int isEmpty(Queue* pQueue);
+
+Queue *ConstructQueue(int limit) {
+    Queue *queue = (Queue*) malloc(sizeof (Queue));
+    if (queue == NULL) {
+        return NULL;
+    }
+    if (limit <= 0) {
+        limit = 65535;
+    }
+    queue->limit = limit;
+    queue->size = 0;
+    queue->head = NULL;
+    queue->tail = NULL;
+
+    return queue;
+}
+
+void DestructQueue(Queue *queue) {
+    NODE *pN;
+    while (!isEmpty(queue)) {
+        pN = Dequeue(queue);
+        free(pN);
+    }
+    free(queue);
+}
+
+int Enqueue(Queue *pQueue, NODE *item) {
+    /* Bad parameter */
+    if ((pQueue == NULL) || (item == NULL)) {
+        return FALSE;
+    }
+    // if(pQueue->limit != 0)
+    if (pQueue->size >= pQueue->limit) {
+        return FALSE;
+    }
+    /*the queue is empty*/
+    item->prev = NULL;
+    if (pQueue->size == 0) {
+        pQueue->head = item;
+        pQueue->tail = item;
+
+    } else {
+        /*adding item to the end of the queue*/
+        pQueue->tail->prev = item;
+        pQueue->tail = item;
+    }
+    pQueue->size++;
+    return TRUE;
+}
+
+NODE * Dequeue(Queue *pQueue) {
+    /*the queue is empty or bad param*/
+    NODE *item;
+    if (isEmpty(pQueue))
+        return NULL;
+    item = pQueue->head;
+    pQueue->head = (pQueue->head)->prev;
+    pQueue->size--;
+    return item;
+}
+
+int isEmpty(Queue* pQueue) {
+    if (pQueue == NULL) {
+        return FALSE;
+    }
+    if (pQueue->size == 0) {
+        return TRUE;
+    } else {
+        return FALSE;
+    }
+}
+/*
+int main() {
+    int i;
+    Queue *pQ = ConstructQueue(7);
+    NODE *pN;
+
+    for (i = 0; i < 9; i++) {
+        pN = (NODE*) malloc(sizeof (NODE));
+        pN->data.info = 100 + i;
+        Enqueue(pQ, pN);
+    }
+
+    while (!isEmpty(pQ)) {
+        pN = Dequeue(pQ);
+        printf("\nDequeued: %d", pN->data);
+        free(pN);
+    }
+    DestructQueue(pQ);
+    return (EXIT_SUCCESS);
+}
+
+*/
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