From ee939d407c1dd915dac7b7915d7ec0d2d80bd914 Mon Sep 17 00:00:00 2001
From: Patrick Mahoney <pat@polycrystal.org>
Date: Sat, 17 Dec 2011 10:05:35 -0600
Subject: [PATCH] Adjust invalid tv_nsec values after adding.

---
 ext/libpsem/psem_posix.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/ext/libpsem/psem_posix.c b/ext/libpsem/psem_posix.c
index 42def6f..6b6dcdf 100644
--- a/ext/libpsem/psem_posix.c
+++ b/ext/libpsem/psem_posix.c
@@ -118,6 +118,7 @@ psem_trywait(psem_t *psem, error_t **err)
 
 #define NS_PER_S (1000 * 1000 * 1000)
 #define US_PER_NS (1000)
+#define TV_NSEC_MAX (NS_PER_S - 1)
 
 int
 psem_timedwait(psem_t *psem, float timeout_s, error_t **err)
@@ -139,6 +140,11 @@ psem_timedwait(psem_t *psem, float timeout_s, error_t **err)
 
     abs_timeout.tv_sec += sec;
     abs_timeout.tv_nsec += nsec;
+
+    while (abs_timeout.tv_nsec > TV_NSEC_MAX) {
+      abs_timeout.tv_sec += 1;
+      abs_timeout.tv_nsec -= NS_PER_S;
+    }
   }
 
   errcheck(sem_timedwait(psem->sem, &abs_timeout), err);