Modify smoothing code to make cubic interpolation optional and allow 'quick fixups' on resuming

The primary reason for this change is to allow time graphs that do not
go through the origin and hence smoothing starting from the origin is
not desired. This change will allow passing time data into the smoother
while paused and then abruptly use that data without smoothing using the
'quick fixup' flag when resuming.

Primary use case is allowing recording time graphs where the data
recorded originates from a time before the stream was created. The
resulting graft will be shifted and should not be smoothened to go
through the origin.

1 files changed, 34 insertions, 7 deletions

diff --git a/src/pulsecore/time-smoother.c b/src/pulsecore/time-smoother.c
index 65621948..55ac8687 100644
--- a/src/pulsecore/time-smoother.c
+++ b/src/pulsecore/time-smoother.c
@@ -78,17 +78,26 @@ struct pa_smoother {
 
     /* Cached parameters for our interpolation polynomial y=ax^3+b^2+cx */
     double a, b, c;
-    pa_bool_t abc_valid;
+    pa_bool_t abc_valid:1;
 
     pa_bool_t monotonic:1;
     pa_bool_t paused:1;
+    pa_bool_t smoothing:1; /* If FALSE we skip the polonyomial interpolation step */
 
     pa_usec_t pause_time;
 
     unsigned min_history;
 };
 
-pa_smoother* pa_smoother_new(pa_usec_t adjust_time, pa_usec_t history_time, pa_bool_t monotonic, unsigned min_history) {
+pa_smoother* pa_smoother_new(
+        pa_usec_t adjust_time,
+        pa_usec_t history_time,
+        pa_bool_t monotonic,
+        pa_bool_t smoothing,
+        unsigned min_history,
+        pa_usec_t time_offset,
+        pa_bool_t paused) {
+
     pa_smoother *s;
 
     pa_assert(adjust_time > 0);
@@ -116,9 +125,13 @@ pa_smoother* pa_smoother_new(pa_usec_t adjust_time, pa_usec_t history_time, pa_b
     s->abc_valid = FALSE;
 
     s->paused = FALSE;
+    s->smoothing = smoothing;
 
     s->min_history = min_history;
 
+    s->paused = paused;
+    s->time_offset = s->pause_time = time_offset;
+
     return s;
 }
 
@@ -278,7 +291,7 @@ static void estimate(pa_smoother *s, pa_usec_t x, pa_usec_t *y, double *deriv) {
     pa_assert(s);
     pa_assert(y);
 
-    if (x >= s->px) {
+    if (!s->smoothing || x >= s->px) {
         int64_t t;
 
         /* The requested point is right of the point where we wanted
@@ -348,7 +361,6 @@ void pa_smoother_put(pa_smoother *s, pa_usec_t x, pa_usec_t y) {
          * we can adjust our position smoothly from this one */
         estimate(s, x, &ney, &nde);
         s->ex = x; s->ey = ney; s->de = nde;
-
         s->ry = y;
     }
 
@@ -359,8 +371,13 @@ void pa_smoother_put(pa_smoother *s, pa_usec_t x, pa_usec_t y) {
     s->dp = avg_gradient(s, x);
 
     /* And calculate when we want to be on track again */
-    s->px = s->ex + s->adjust_time;
-    s->py = s->ry + (pa_usec_t) llrint(s->dp * (double) s->adjust_time);
+    if (s->smoothing) {
+        s->px = s->ex + s->adjust_time;
+        s->py = s->ry + (pa_usec_t) llrint(s->dp * (double) s->adjust_time);
+    } else {
+        s->px = s->ex;
+        s->py = s->ry;
+    }
 
     s->abc_valid = FALSE;
 
@@ -420,7 +437,7 @@ void pa_smoother_pause(pa_smoother *s, pa_usec_t x) {
     s->pause_time = x;
 }
 
-void pa_smoother_resume(pa_smoother *s, pa_usec_t x) {
+void pa_smoother_resume(pa_smoother *s, pa_usec_t x, pa_bool_t fix_now) {
     pa_assert(s);
 
     if (!s->paused)
@@ -433,6 +450,16 @@ void pa_smoother_resume(pa_smoother *s, pa_usec_t x) {
 
     s->paused = FALSE;
     s->time_offset += x - s->pause_time;
+
+    if (fix_now)
+        pa_smoother_fix_now(s);
+}
+
+void pa_smoother_fix_now(pa_smoother *s) {
+    pa_assert(s);
+
+    s->px = s->ex;
+    s->py = s->ry;
 }
 
 pa_usec_t pa_smoother_translate(pa_smoother *s, pa_usec_t x, pa_usec_t y_delay) {