+static void sink_update_requested_latency_cb(pa_sink *s) {
+ struct userdata *u;
+ size_t nbytes;
+
+ pa_sink_assert_ref(s);
+ pa_assert_se(u = s->userdata);
+
+ u->block_usec = pa_sink_get_requested_latency_within_thread(s);
+
+ if (u->block_usec == (pa_usec_t) -1)
+ u->block_usec = s->thread_info.max_latency;
+
+ nbytes = pa_usec_to_bytes(u->block_usec, &s->sample_spec);
+ pa_sink_set_max_rewind_within_thread(s, nbytes);
+ pa_sink_set_max_request_within_thread(s, nbytes);
+}
+
+static void process_rewind(struct userdata *u, pa_usec_t now) {
+ size_t rewind_nbytes, in_buffer;
+ pa_usec_t delay;
+
+ pa_assert(u);
+
+ rewind_nbytes = u->sink->thread_info.rewind_nbytes;
+
+ if (!PA_SINK_IS_OPENED(u->sink->thread_info.state) || rewind_nbytes <= 0)
+ goto do_nothing;
+
+ pa_log_debug("Requested to rewind %lu bytes.", (unsigned long) rewind_nbytes);
+
+ if (u->timestamp <= now)
+ goto do_nothing;
+
+ delay = u->timestamp - now;
+ in_buffer = pa_usec_to_bytes(delay, &u->sink->sample_spec);
+
+ if (in_buffer <= 0)
+ goto do_nothing;
+
+ if (rewind_nbytes > in_buffer)
+ rewind_nbytes = in_buffer;
+
+ pa_sink_process_rewind(u->sink, rewind_nbytes);
+ u->timestamp -= pa_bytes_to_usec(rewind_nbytes, &u->sink->sample_spec);
+
+ pa_log_debug("Rewound %lu bytes.", (unsigned long) rewind_nbytes);
+ return;
+
+do_nothing:
+
+ pa_sink_process_rewind(u->sink, 0);
+}
+
+static void process_render(struct userdata *u, pa_usec_t now) {
+ size_t ate = 0;
+
+ pa_assert(u);
+
+ /* This is the configured latency. Sink inputs connected to us
+ might not have a single frame more than the maxrequest value
+ queued. Hence: at maximum read this many bytes from the sink
+ inputs. */
+
+ /* Fill the buffer up the latency size */
+ while (u->timestamp < now + u->block_usec) {
+ pa_memchunk chunk;
+
+ pa_sink_render(u->sink, u->sink->thread_info.max_request, &chunk);
+ pa_memblock_unref(chunk.memblock);
+
+/* pa_log_debug("Ate %lu bytes.", (unsigned long) chunk.length); */
+ u->timestamp += pa_bytes_to_usec(chunk.length, &u->sink->sample_spec);
+
+ ate += chunk.length;
+
+ if (ate >= u->sink->thread_info.max_request)
+ break;
+ }
+
+/* pa_log_debug("Ate in sum %lu bytes (of %lu)", (unsigned long) ate, (unsigned long) nbytes); */
+}
+