add generic rate limiting implementation

src/pulsecore/ratelimit.h

@@ -0,0 +1,46 @@
+#ifndef foopulsecoreratelimithfoo
+#define foopulsecoreratelimithfoo
+
+/***
+  This file is part of PulseAudio.
+
+  Copyright 2009 Lennart Poettering
+
+  PulseAudio 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 2 of the
+  License, or (at your option) any later version.
+
+  PulseAudio 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
+  General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with PulseAudio; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+***/
+
+#include <pulse/sample.h>
+#include <pulsecore/macro.h>
+
+typedef struct pa_ratelimit {
+    const pa_usec_t interval;
+    const unsigned burst;
+    unsigned n_printed, n_missed;
+    pa_usec_t begin;
+} pa_ratelimit;
+
+#define PA_DEFINE_RATELIMIT(_name, _interval, _burst)   \
+    pa_ratelimit _name = {                              \
+        .interval = _interval,                          \
+        .burst = _burst,                                \
+        .n_printed = 0,                                 \
+        .n_missed = 0,                                  \
+        .begin = 0                                      \
+    }
+
+pa_bool_t pa_ratelimit_test(pa_ratelimit *r);
+
+#endif