1 files changed, 105 insertions, 0 deletions
diff --git a/src/libmowgli/mowgli_spinlock.c b/src/libmowgli/mowgli_spinlock.c
new file mode 100644
index 0000000..47c1166
--- /dev/null
+++ b/src/libmowgli/mowgli_spinlock.c
@@ -0,0 +1,105 @@
+/*
+ * libmowgli: A collection of useful routines for programming.
+ * mowgli_spinlock.c: Spinlocks.
+ *
+ * Copyright (c) 2007 William Pitcock <nenolod -at- sacredspiral.co.uk>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice is present in all copies.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "mowgli.h"
+
+mowgli_spinlock_t *mowgli_spinlock_create(void)
+{
+	mowgli_spinlock_t *out = mowgli_alloc(sizeof(mowgli_spinlock_t));
+
+	return out;
+}
+
+void mowgli_spinlock_lock(mowgli_spinlock_t *self, void *r, void *w)
+{
+	return_if_fail(self != NULL);
+
+	if (r)
+		mowgli_spinlock_wait(self, MOWGLI_SPINLOCK_READ);
+
+	if (w)
+		mowgli_spinlock_wait(self, MOWGLI_SPINLOCK_WRITE);
+
+	if (r && (self->read_owner == NULL || self->read_owner == r))
+		self->read_owner = r;
+
+	if (w && (self->write_owner == NULL || self->write_owner == w))
+		self->write_owner = w;
+}
+
+void mowgli_spinlock_unlock(mowgli_spinlock_t *self, void *r, void *w)
+{
+	return_if_fail(self != NULL);
+
+	if (r && self->read_owner == r)
+		self->read_owner = NULL;
+
+	if (w && self->write_owner == w)
+		self->write_owner = NULL;
+}
+
+void mowgli_spinlock_wait(mowgli_spinlock_t *self, mowgli_spinlock_lock_param_t param)
+{
+	return_if_fail(self != NULL)
+
+	if (param == MOWGLI_SPINLOCK_READ)
+		while (self->read_owner != NULL)
+			usleep(1000);	/* XXX: we'll want a more threadsafe function eventually. */
+
+	if (param == MOWGLI_SPINLOCK_WRITE)
+		while (self->write_owner != NULL)
+			usleep(1000);
+
+	if (param == MOWGLI_SPINLOCK_READWRITE)
+		while (self->write_owner != NULL || self->read_owner != NULL)
+			usleep(1000);
+}
+
+void mowgli_spinlock_timed_wait(mowgli_spinlock_t *self, mowgli_spinlock_lock_param_t param, struct timeval *tv)
+{
+	struct timeval iter = {0};
+
+	return_if_fail(self != NULL)
+	return_if_fail(tv != NULL)
+
+	if (param == MOWGLI_SPINLOCK_READ)
+		while (self->read_owner != NULL && iter.tv_sec < tv->tv_sec && iter.tv_usec < tv->tv_usec)
+		{
+			gettimeofday(&iter, NULL);
+			usleep(1000);	/* XXX: we'll want a more threadsafe function eventually. */
+		}
+
+	if (param == MOWGLI_SPINLOCK_WRITE)
+		while (self->write_owner != NULL && iter.tv_sec < tv->tv_sec && iter.tv_usec < tv->tv_usec)
+		{
+			gettimeofday(&iter, NULL);
+			usleep(1000);
+		}
+
+	if (param == MOWGLI_SPINLOCK_READWRITE)
+		while ((self->write_owner != NULL || self->read_owner != NULL) && iter.tv_sec < tv->tv_sec && iter.tv_usec < tv->tv_usec)
+		{
+			gettimeofday(&iter, NULL);
+			usleep(1000);	
+		}
+}