add new API function pa_timeval_add()

git-svn-id: file:///home/lennart/svn/public/pulseaudio/branches/glitch-free@2240 fefdeb5f-60dc-0310-8127-8f9354f1896f

2 files changed, 23 insertions, 1 deletions

diff --git a/src/pulse/timeval.c b/src/pulse/timeval.c
index 70ceb71e..180e0159 100644
--- a/src/pulse/timeval.c
+++ b/src/pulse/timeval.c
@@ -148,6 +148,24 @@ struct timeval* pa_timeval_add(struct timeval *tv, pa_usec_t v) {
     return tv;
 }
 
+struct timeval* pa_timeval_sub(struct timeval *tv, pa_usec_t v) {
+    unsigned long secs;
+    pa_assert(tv);
+
+    secs = (unsigned long) (v/PA_USEC_PER_SEC);
+    tv->tv_sec -= secs;
+    v -= ((pa_usec_t) secs) * PA_USEC_PER_SEC;
+
+    if (tv->tv_usec >= (suseconds_t) v)
+        tv->tv_usec -= (suseconds_t) v;
+    else {
+        tv->tv_sec --;
+        tv->tv_usec = tv->tv_usec + PA_USEC_PER_SEC - v;
+    }
+
+    return tv;
+}
+
 struct timeval* pa_timeval_store(struct timeval *tv, pa_usec_t v) {
     pa_assert(tv);
 
diff --git a/src/pulse/timeval.h b/src/pulse/timeval.h
index 65a0e513..315f4190 100644
--- a/src/pulse/timeval.h
+++ b/src/pulse/timeval.h
@@ -26,6 +26,7 @@
 ***/
 
 #include <pulse/cdecl.h>
+#include <pulse/gccmacro.h>
 #include <pulse/sample.h>
 
 /** \file
@@ -54,7 +55,10 @@ int pa_timeval_cmp(const struct timeval *a, const struct timeval *b) PA_GCC_PURE
 pa_usec_t pa_timeval_age(const struct timeval *tv);
 
 /** Add the specified time inmicroseconds to the specified timeval structure */
-struct timeval* pa_timeval_add(struct timeval *tv, pa_usec_t v) PA_GCC_PURE;
+struct timeval* pa_timeval_add(struct timeval *tv, pa_usec_t v);
+
+/** Subtract the specified time inmicroseconds to the specified timeval structure. \since 0.9.11 */
+struct timeval* pa_timeval_sub(struct timeval *tv, pa_usec_t v);
 
 /** Store the specified uec value in the timeval struct. \since 0.9.7 */
 struct timeval* pa_timeval_store(struct timeval *tv, pa_usec_t v);