Get rid of some warnings

Mostly warnings about unused stuff.
Furthermore, the first hunk is a fix for the change in 177948a6.
Finally, comment in AEC_dtd was translated and the code simplified slightly.

CC     module_bluetooth_device_la-module-bluetooth-device.lo
modules/bluetooth/module-bluetooth-device.c: In function ‘a2dp_process_render’:
modules/bluetooth/module-bluetooth-device.c:1335:30: warning: pointer targets in passing argument 6 of ‘sbc_encode’
differ in signedness [-Wpointer-sign]
../src/modules/bluetooth/sbc/sbc.h:92:9: note: expected ‘ssize_t *’ but argument is of type ‘size_t *’

CC     module_rygel_media_server_la-module-rygel-media-server.lo
modules/module-rygel-media-server.c:383:13: warning: ‘append_property_dict_entry_object_array’ defined but not used [-Wunused-function]

CC     module_echo_cancel_la-adrian-aec.lo
modules/echo-cancel/adrian-aec.h:360:15: warning: ‘AEC_getambient’ defined but not used [-Wunused-function]
modules/echo-cancel/adrian-aec.h:368:14: warning: ‘AEC_setgain’ defined but not used [-Wunused-function]
modules/echo-cancel/adrian-aec.h:374:14: warning: ‘AEC_setaes’ defined but not used [-Wunused-function]
modules/echo-cancel/adrian-aec.h:377:16: warning: ‘AEC_max_dotp_xf_xf’ declared ‘static’ but never defined [-Wunused-function]

CC     module_echo_cancel_la-module-echo-cancel.lo
modules/echo-cancel/module-echo-cancel.c: In function ‘time_callback’:
modules/echo-cancel/module-echo-cancel.c:266:12: warning: variable ‘fs’ set but not used [-Wunused-but-set-variable]

CC     module-virtual-sink.lo
modules/module-virtual-sink.c: In function ‘sink_input_pop_cb’:
modules/module-virtual-sink.c:206:15: warning: variable ‘current_latency’ set but not used [-Wunused-but-set-variable]

7 files changed, 17 insertions, 21 deletions

diff --git a/src/modules/bluetooth/module-bluetooth-device.c b/src/modules/bluetooth/module-bluetooth-device.c
index 55610546..ac0f16fc 100644
--- a/src/modules/bluetooth/module-bluetooth-device.c
+++ b/src/modules/bluetooth/module-bluetooth-device.c
@@ -1326,7 +1326,7 @@ static int a2dp_process_render(struct userdata *u) {
     to_write = a2dp->buffer_size - sizeof(*header) - sizeof(*payload);
 
     while (PA_LIKELY(to_encode > 0 && to_write > 0)) {
-        size_t written;
+        ssize_t written;
         ssize_t encoded;
 
         encoded = sbc_encode(&a2dp->sbc,
diff --git a/src/modules/echo-cancel/adrian-aec.c b/src/modules/echo-cancel/adrian-aec.c
index 6793e59d..04b31e91 100644
--- a/src/modules/echo-cancel/adrian-aec.c
+++ b/src/modules/echo-cancel/adrian-aec.c
@@ -107,8 +107,7 @@ AEC* AEC_init(int RATE, int have_vector)
 // mapped to 1.0 with a limited linear function.
 static float AEC_dtd(AEC *a, REAL d, REAL x)
 {
-  float stepsize;
-  float ratio, M;
+  float ratio, stepsize;
 
   // fast near-end and far-end average
   a->dfast += ALPHAFAST * (fabsf(d) - a->dfast);
@@ -129,16 +128,13 @@ static float AEC_dtd(AEC *a, REAL d, REAL x)
   // ratio of NFRs
   ratio = (a->dfast * a->xslow) / (a->dslow * a->xfast);
 
-  // begrenzte lineare Kennlinie
-  M = (STEPY2 - STEPY1) / (STEPX2 - STEPX1);
-  if (ratio < STEPX1) {
+  // Linear interpolation with clamping at the limits
+  if (ratio < STEPX1)
     stepsize = STEPY1;
-  } else if (ratio > STEPX2) {
+  else if (ratio > STEPX2)
     stepsize = STEPY2;
-  } else {
-    // Punktrichtungsform einer Geraden
-    stepsize = M * (ratio - STEPX1) + STEPY1;
-  }
+  else
+    stepsize = STEPY1 + (STEPY2 - STEPY1) * (ratio - STEPX1) / (STEPX2 - STEPX1);
 
   return stepsize;
 }
diff --git a/src/modules/echo-cancel/adrian-aec.h b/src/modules/echo-cancel/adrian-aec.h
index 235984be..9c722b9d 100644
--- a/src/modules/echo-cancel/adrian-aec.h
+++ b/src/modules/echo-cancel/adrian-aec.h
@@ -357,7 +357,7 @@ static  REAL AEC_nlms_pw(AEC *a, REAL d, REAL x_, float stepsize);
  */
   int AEC_doAEC(AEC *a, int d_, int x_);
 
-static  float AEC_getambient(AEC *a) {
+PA_GCC_UNUSED static  float AEC_getambient(AEC *a) {
     return a->dfast;
   };
 static  void AEC_setambient(AEC *a, float Min_xf) {
@@ -365,16 +365,15 @@ static  void AEC_setambient(AEC *a, float Min_xf) {
     a->delta = (NLMS_LEN-1) * Min_xf * Min_xf;
     a->dotp_xf_xf += a->delta;  // add new delta
   };
-static  void AEC_setgain(AEC *a, float gain_) {
+PA_GCC_UNUSED static  void AEC_setgain(AEC *a, float gain_) {
     a->gain = gain_;
   };
 #if 0
   void AEC_openwdisplay(AEC *a);
 #endif
-static  void AEC_setaes(AEC *a, float aes_y2_) {
+PA_GCC_UNUSED static  void AEC_setaes(AEC *a, float aes_y2_) {
     a->aes_y2 = aes_y2_;
   };
-static  double AEC_max_dotp_xf_xf(AEC *a, double u);
 
 #define _AEC_H
 #endif
diff --git a/src/modules/echo-cancel/module-echo-cancel.c b/src/modules/echo-cancel/module-echo-cancel.c
index a3ad1698..74e4d588 100644
--- a/src/modules/echo-cancel/module-echo-cancel.c
+++ b/src/modules/echo-cancel/module-echo-cancel.c
@@ -263,7 +263,7 @@ static void time_callback(pa_mainloop_api *a, pa_time_event *e, const struct tim
     struct userdata *u = userdata;
     uint32_t old_rate, base_rate, new_rate;
     int64_t diff_time;
-    size_t fs;
+    /*size_t fs*/;
     struct snapshot latency_snapshot;
 
     pa_assert(u);
@@ -281,7 +281,7 @@ static void time_callback(pa_mainloop_api *a, pa_time_event *e, const struct tim
     /* calculate drift between capture and playback */
     diff_time = calc_diff(u, &latency_snapshot);
 
-    fs = pa_frame_size(&u->source_output->sample_spec);
+    /*fs = pa_frame_size(&u->source_output->sample_spec);*/
     old_rate = u->sink_input->sample_spec.rate;
     base_rate = u->source_output->sample_spec.rate;
 
@@ -290,7 +290,7 @@ static void time_callback(pa_mainloop_api *a, pa_time_event *e, const struct tim
          * canceler does not work in this case. */
         pa_asyncmsgq_post(u->asyncmsgq, PA_MSGOBJECT(u->source_output), SOURCE_OUTPUT_MESSAGE_APPLY_DIFF_TIME,
             NULL, diff_time, NULL, NULL);
-        //new_rate = base_rate - ((pa_usec_to_bytes(-diff_time, &u->source_output->sample_spec) / fs) * PA_USEC_PER_SEC) / u->adjust_time;
+        /*new_rate = base_rate - ((pa_usec_to_bytes(-diff_time, &u->source_output->sample_spec) / fs) * PA_USEC_PER_SEC) / u->adjust_time;*/
         new_rate = base_rate;
     }
     else {
@@ -301,7 +301,7 @@ static void time_callback(pa_mainloop_api *a, pa_time_event *e, const struct tim
         }
 
         /* recording behind playback, we need to slowly adjust the rate to match */
-        //new_rate = base_rate + ((pa_usec_to_bytes(diff_time, &u->source_output->sample_spec) / fs) * PA_USEC_PER_SEC) / u->adjust_time;
+        /*new_rate = base_rate + ((pa_usec_to_bytes(diff_time, &u->source_output->sample_spec) / fs) * PA_USEC_PER_SEC) / u->adjust_time;*/
 
         /* assume equal samplerates for now */
         new_rate = base_rate;
diff --git a/src/modules/module-rygel-media-server.c b/src/modules/module-rygel-media-server.c
index 9d23e8a4..f34142cd 100644
--- a/src/modules/module-rygel-media-server.c
+++ b/src/modules/module-rygel-media-server.c
@@ -380,6 +380,7 @@ static void append_variant_item_display_name(DBusMessage *m, DBusMessageIter *it
     append_variant_string(m, iter, display_name);
 }
 
+PA_GCC_UNUSED
 static void append_property_dict_entry_object_array(DBusMessage *m, DBusMessageIter *iter, const char *name, const char *path[], unsigned n) {
     DBusMessageIter sub;
 
diff --git a/src/modules/module-virtual-sink.c b/src/modules/module-virtual-sink.c
index cc134900..f7723148 100644
--- a/src/modules/module-virtual-sink.c
+++ b/src/modules/module-virtual-sink.c
@@ -203,7 +203,7 @@ static int sink_input_pop_cb(pa_sink_input *i, size_t nbytes, pa_memchunk *chunk
     size_t fs;
     unsigned n, c;
     pa_memchunk tchunk;
-    pa_usec_t current_latency;
+    pa_usec_t current_latency PA_GCC_UNUSED;
 
     pa_sink_input_assert_ref(i);
     pa_assert(chunk);
diff --git a/src/pulse/gccmacro.h b/src/pulse/gccmacro.h
index 57e80509..5749a6bb 100644
--- a/src/pulse/gccmacro.h
+++ b/src/pulse/gccmacro.h
@@ -49,7 +49,7 @@
 #ifdef __GNUC__
 #define PA_GCC_UNUSED __attribute__ ((unused))
 #else
-/** Macro for not used parameter */
+/** Macro for not used function, variable or parameter */
 #define PA_GCC_UNUSED
 #endif