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-rw-r--r--linuxthreads/queue.h62
1 files changed, 62 insertions, 0 deletions
diff --git a/linuxthreads/queue.h b/linuxthreads/queue.h
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+++ b/linuxthreads/queue.h
@@ -0,0 +1,62 @@
+/* Linuxthreads - a simple clone()-based implementation of Posix        */
+/* threads for Linux.                                                   */
+/* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr)              */
+/*                                                                      */
+/* This program is free software; you can redistribute it and/or        */
+/* modify it under the terms of the GNU Library General Public License  */
+/* as published by the Free Software Foundation; either version 2       */
+/* of the License, or (at your option) any later version.               */
+/*                                                                      */
+/* This program is distributed in the hope that it will be useful,      */
+/* but WITHOUT ANY WARRANTY; without even the implied warranty of       */
+/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        */
+/* GNU Library General Public License for more details.                 */
+
+/* Waiting queues */
+
+typedef struct _pthread_queue pthread_queue;
+
+static inline void queue_init(pthread_queue * q)
+{
+  q->head = q->tail = NULL;
+}
+
+static inline void enqueue(pthread_queue * q, pthread_descr th)
+{
+  int prio;
+  pthread_descr * elt;
+
+  ASSERT(th->p_nextwaiting == NULL);
+  if (q->tail == NULL) {
+    q->head = th;
+    q->tail = th;
+    return;
+  }
+  prio = th->p_priority;
+  if (prio > 0) {
+    /* Insert in queue according to priority order */
+    for (elt = &(q->head); *elt != NULL; elt = &((*elt)->p_nextwaiting)) {
+      if (prio > (*elt)->p_priority) {
+        th->p_nextwaiting = *elt;
+        *elt = th;
+        return;
+      }
+    }
+  }
+  /* Priority is no greater than any thread in the queue.
+     Insert at end of queue */
+  q->tail->p_nextwaiting = th;
+  q->tail = th;
+}
+
+static inline pthread_descr dequeue(pthread_queue * q)
+{
+  pthread_descr th;
+  th = q->head;
+  if (th != NULL) {
+    q->head = th->p_nextwaiting;
+    if (q->head == NULL) q->tail = NULL;
+    th->p_nextwaiting = NULL;
+  }
+  return th;
+}