1 files changed, 164 insertions, 0 deletions
diff --git a/libdimension/future.c b/libdimension/future.c
new file mode 100644
index 0000000..c328815
--- /dev/null
+++ b/libdimension/future.c
@@ -0,0 +1,164 @@
+/*************************************************************************
+ * Copyright (C) 2009-2011 Tavian Barnes <tavianator@tavianator.com>     *
+ *                                                                       *
+ * This file is part of The Dimension Library.                           *
+ *                                                                       *
+ * The Dimension Library is free software; you can redistribute it and/  *
+ * or modify it under the terms of the GNU Lesser General Public License *
+ * as published by the Free Software Foundation; either version 3 of the *
+ * License, or (at your option) any later version.                       *
+ *                                                                       *
+ * The Dimension Library 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  *
+ * Lesser General Public License for more details.                       *
+ *                                                                       *
+ * You should have received a copy of the GNU Lesser General Public      *
+ * License along with this program.  If not, see                         *
+ * <http://www.gnu.org/licenses/>.                                       *
+ *************************************************************************/
+
+/**
+ * @file
+ * Future objects.
+ */
+
+#include "dimension-internal.h"
+#include <pthread.h>
+
+/* Allocate a new dmnsn_future* */
+dmnsn_future *
+dmnsn_new_future(void)
+{
+  dmnsn_future *future = dmnsn_malloc(sizeof(dmnsn_future));
+  future->progress = 0;
+  future->total    = 1;
+
+  /* Initialize the rwlock, condition variable, and mutex */
+
+  future->rwlock = dmnsn_malloc(sizeof(pthread_rwlock_t));
+  dmnsn_initialize_rwlock(future->rwlock);
+
+  future->cond = dmnsn_malloc(sizeof(pthread_cond_t));
+  dmnsn_initialize_cond(future->cond);
+
+  future->mutex = dmnsn_malloc(sizeof(pthread_mutex_t));
+  dmnsn_initialize_mutex(future->mutex);
+
+  future->min_wait = dmnsn_malloc(sizeof(double));
+  *future->min_wait = 1.0;
+
+  return future;
+}
+
+/* Join the worker thread and delete `future'. */
+int
+dmnsn_future_join(dmnsn_future *future)
+{
+  void *ptr;
+  int retval = -1;
+
+  if (future) {
+    /* Get the thread's return value */
+    dmnsn_join_thread(future->thread, &ptr);
+    if (ptr && ptr != PTHREAD_CANCELED) {
+      retval = *(int *)ptr;
+      dmnsn_free(ptr);
+    }
+
+    /* Free the future object */
+
+    dmnsn_free(future->min_wait);
+
+    dmnsn_destroy_mutex(future->mutex);
+    dmnsn_free(future->mutex);
+
+    dmnsn_destroy_cond(future->cond);
+    dmnsn_free(future->cond);
+
+    dmnsn_destroy_rwlock(future->rwlock);
+    dmnsn_free(future->rwlock);
+
+    dmnsn_free(future);
+  }
+
+  return retval;
+}
+
+/* Cancel a background thread */
+void
+dmnsn_future_cancel(dmnsn_future *future)
+{
+  pthread_cancel(future->thread);
+}
+
+/* Get the current progress of the worker thread, in [0.0, 1.0] */
+double
+dmnsn_future_progress(const dmnsn_future *future)
+{
+  double progress;
+
+  dmnsn_read_lock(future->rwlock);
+    progress = (double)future->progress/future->total;
+  dmnsn_unlock_rwlock(future->rwlock);
+
+  return progress;
+}
+
+/* Wait until dmnsn_future_progress(future) >= progress */
+void
+dmnsn_future_wait(const dmnsn_future *future, double progress)
+{
+  dmnsn_lock_mutex(future->mutex);
+    while (dmnsn_future_progress(future) < progress) {
+      /* Set the minimum waited-on value */
+      if (progress < *future->min_wait)
+        *future->min_wait = progress;
+
+      dmnsn_cond_wait(future->cond, future->mutex);
+    }
+  dmnsn_unlock_mutex(future->mutex);
+}
+
+/* Set the total number of loop iterations */
+void
+dmnsn_future_set_total(dmnsn_future *future, size_t total)
+{
+  dmnsn_write_lock(future->rwlock);
+    future->total = total;
+  dmnsn_unlock_rwlock(future->rwlock);
+}
+
+/* Increment the number of completed loop iterations */
+void
+dmnsn_future_increment(dmnsn_future *future)
+{
+  /* Allow a thread to be canceled whenever it increments a future object --
+     this is close to PTHREAD_CANCEL_ASYNCHRONOUS but allows consistent state
+     on cancellation */
+  pthread_testcancel();
+
+  dmnsn_write_lock(future->rwlock);
+    ++future->progress;
+  dmnsn_unlock_rwlock(future->rwlock);
+
+  dmnsn_lock_mutex(future->mutex);
+    if (dmnsn_future_progress(future) >= *future->min_wait) {
+      *future->min_wait = 1.0;
+      dmnsn_cond_broadcast(future->cond);
+    }
+  dmnsn_unlock_mutex(future->mutex);
+}
+
+/* Immediately set to 100% completion */
+void
+dmnsn_future_done(dmnsn_future *future)
+{
+  dmnsn_write_lock(future->rwlock);
+    future->progress = future->total;
+  dmnsn_unlock_rwlock(future->rwlock);
+
+  dmnsn_lock_mutex(future->mutex);
+    dmnsn_cond_broadcast(future->cond);
+  dmnsn_unlock_mutex(future->mutex);
+}