From 47f828f11b985fec6c92818378a1bfbb51e1bc6c Mon Sep 17 00:00:00 2001
From: jluehrs2 <jluehrs2@uiuc.edu>
Date: Tue, 9 Oct 2007 00:01:26 -0500
Subject: initial working implementation of installing signal handlers

---
 src/queue.c | 80 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 src/queue.c

(limited to 'src/queue.c')

diff --git a/src/queue.c b/src/queue.c
new file mode 100644
index 0000000..012e986
--- /dev/null
+++ b/src/queue.c
@@ -0,0 +1,80 @@
+#include "queue.h"
+#include <stdlib.h>
+
+static int _queue_resize(queue* q, int new_cap)
+{
+    int* new_queue;
+    int i;
+
+    if (new_cap <= q->cap) {
+        return 0;
+    }
+    if ((new_queue = (int*)malloc(new_cap * sizeof(int))) == NULL) {
+        return 0;
+    }
+    if (q->front <= q->back) {
+        q->front = q->front + q->cap;
+    }
+    for (i = q->back; i < q->front; ++i) {
+        new_queue[i - q->back] = q->queue[i % q->cap];
+    }
+    free(q->queue);
+    q->queue = new_queue;
+    q->cap = new_cap;
+    q->front = q->size;
+    q->back = 0;
+
+    return 1;
+}
+
+int queue_init(queue* q, int cap)
+{
+    if (cap < 1) {
+        return 0;
+    }
+    if ((q->queue = (int*)malloc(cap * sizeof(int))) == NULL) {
+        return 0;
+    }
+    q->size = 0;
+    q->cap = cap;
+    q->front = 0;
+    q->back = 0;
+
+    return 1;
+}
+
+int enqueue(queue* q, int item)
+{
+    if (q->size == q->cap) {
+        if (!_queue_resize(q, 2 * q->cap)) {
+            return 0;
+        }
+    }
+    q->queue[q->front++] = item;
+    q->front %= q->cap;
+    ++q->size;
+
+    return 1;
+}
+
+int dequeue(queue* q)
+{
+    int ret;
+
+    if (q->size == 0) {
+        return -1;
+    }
+    ret = q->queue[q->back++];
+    q->back %= q->cap;
+    --q->size;
+
+    return ret;
+}
+
+void queue_delete(queue* q)
+{
+    free(q->queue);
+    q->queue = NULL;
+    q->size = 0;
+    q->cap = 0;
+}
-- 
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