Fix an issue where a ResamplingQueue could reach unbounded length.

This would happen if we stared asking for samples before the first insert,
causing the correction factor to become NaN and everything to go south.
This would also seemingly eventually cause panic messages when we believed we
were out of data in the same queue.

diff --git a/resampling_queue.cpp b/resampling_queue.cpp
index 109c42060307c3b0450b7799c814e4168477b268..ab20b410623b348d3fab0b6ff65753f128e1747e 100644 (file)
--- a/resampling_queue.cpp
+++ b/resampling_queue.cpp
@@ -19,6 +19,7 @@
 
 #include "resampling_queue.h"
 
+#include <assert.h>
 #include <math.h>
 #include <stddef.h>
 #include <stdio.h>
@@ -39,6 +40,9 @@ ResamplingQueue::ResamplingQueue(unsigned freq_in, unsigned freq_out, unsigned n
 
 void ResamplingQueue::add_input_samples(double pts, const float *samples, ssize_t num_samples)
 {
+       if (num_samples == 0) {
+               return;
+       }
        if (first_input) {
                // Synthesize a fake length.
                last_input_len = double(num_samples) / freq_in;
@@ -59,6 +63,12 @@ void ResamplingQueue::add_input_samples(double pts, const float *samples, ssize_
 
 bool ResamplingQueue::get_output_samples(double pts, float *samples, ssize_t num_samples)
 {
+       if (first_input) {
+               // No data yet, just return zeros.
+               memset(samples, 0, num_samples * 2 * sizeof(float));
+               return true;
+       }
+
        double last_output_len;
        if (first_output) {
                // Synthesize a fake length.
@@ -71,6 +81,7 @@ bool ResamplingQueue::get_output_samples(double pts, float *samples, ssize_t num
        // Using the time point since just before the last call to add_input_samples() as a base,
        // estimate actual delay based on activity since then, measured in number of input samples:
        double actual_delay = 0.0;
+       assert(last_input_len != 0);
        actual_delay += (k_a1 - k_a0) * last_output_len / last_input_len;    // Inserted samples since k_a0, rescaled for the different time periods.
        actual_delay += k_a0 - total_consumed_samples;                       // Samples inserted before k_a0 but not consumed yet.
        actual_delay += vresampler.inpdist();                                // Delay in the resampler itself.
@@ -108,6 +119,7 @@ bool ResamplingQueue::get_output_samples(double pts, float *samples, ssize_t num
        double rcorr = 1.0 - z2 - z3;
        if (rcorr > 1.05) rcorr = 1.05;
        if (rcorr < 0.95) rcorr = 0.95;
+       assert(!isnan(rcorr));
        vresampler.set_rratio(rcorr);
 
        // Finally actually resample, consuming exactly <num_samples> output samples.