Add copy of opus library in deps/third_party.

opus/celt/tests/test_unit_rotation.c

+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#ifndef CUSTOM_MODES
+#define CUSTOM_MODES
+#endif
+
+#define CELT_C
+
+#include <stdio.h>
+#include <stdlib.h>
+#include "vq.c"
+#include "cwrs.c"
+#include "entcode.c"
+#include "entenc.c"
+#include "entdec.c"
+#include "mathops.c"
+#include "bands.h"
+#include <math.h>
+#define MAX_SIZE 100
+
+int ret=0;
+void test_rotation(int N, int K)
+{
+   int i;
+   double err = 0, ener = 0, snr, snr0;
+   opus_val16 x0[MAX_SIZE];
+   opus_val16 x1[MAX_SIZE];
+   for (i=0;i<N;i++)
+      x1[i] = x0[i] = rand()%32767-16384;
+   exp_rotation(x1, N, 1, 1, K, SPREAD_NORMAL);
+   for (i=0;i<N;i++)
+   {
+      err += (x0[i]-(double)x1[i])*(x0[i]-(double)x1[i]);
+      ener += x0[i]*(double)x0[i];
+   }
+   snr0 = 20*log10(ener/err);
+   err = ener = 0;
+   exp_rotation(x1, N, -1, 1, K, SPREAD_NORMAL);
+   for (i=0;i<N;i++)
+   {
+      err += (x0[i]-(double)x1[i])*(x0[i]-(double)x1[i]);
+      ener += x0[i]*(double)x0[i];
+   }
+   snr = 20*log10(ener/err);
+   printf ("SNR for size %d (%d pulses) is %f (was %f without inverse)\n", N, K, snr, snr0);
+   if (snr < 60 || snr0 > 20)
+   {
+      fprintf(stderr, "FAIL!\n");
+      ret = 1;
+   }
+}
+
+int main(void)
+{
+   ALLOC_STACK;
+   test_rotation(15, 3);
+   test_rotation(23, 5);
+   test_rotation(50, 3);
+   test_rotation(80, 1);
+   return ret;
+}