adjust root folder

ports/dos/queue.c

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+/*
++----------------------------------------------------+
+|               Thunderbird Software                 |
++----------------------------------------------------+
+| Filespec  :  Queue.c                               |
+| Date      :  September 29, 1994                    |
+| Time      :  10:16AM                               |
+| Revision  :  1.0                                   |
++----------------------------------------------------+
+| Programmer:  Scott Andrews                         |
+| Address   :  5358 Summit RD SW                     |
+| City/State:  Pataskala, Ohio                       |
+| Zip       :  43062                                 |
++----------------------------------------------------+
+| Released to the Public Domain                      |
++----------------------------------------------------+
+*/
+
+#include <stdlib.h>
+
+#include "queue.h"
+
+QUEUE *alloc_queue(
+    int size)
+{
+    QUEUE *retval;
+    retval = (QUEUE *) malloc(sizeof(QUEUE) + (size_t) size);
+    if ((QUEUE *) 0 != retval) {
+        retval->size = size;
+        retval->head = 0;
+        retval->tail = 0;
+        retval->avail = size;
+        retval->buffer = ((char *) retval) + sizeof(QUEUE);
+    }
+    return retval;
+}
+
+int en_queue(
+    QUEUE * queue,
+    char data)
+{
+    int retval = -1;
+    if (0 != queue->avail) {
+        *(queue->buffer + queue->head) = data;
+        queue->head += 1;
+        if (queue->head == queue->size)
+            queue->head = 0;
+        queue->avail -= 1;
+        retval = queue->avail;
+    }
+    return retval;
+}
+
+int de_queue(
+    QUEUE * queue)
+{
+    int retval = -1;
+    if (queue->avail != queue->size) {
+        retval = *(queue->buffer + queue->tail);
+        queue->tail += 1;
+        if (queue->tail == queue->size)
+            queue->tail = 0;
+        queue->avail += 1;
+    }
+    return retval;
+}
+
+/* End of Queue.c */