seeking in stb_vorbis (Dougall Johnson)

test program for seeking (stb)

tests/vorbseek/vorbseek.c

@@ -0,0 +1,105 @@
+#include <assert.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#define STB_VORBIS_HEADER_ONLY
+#include "stb_vorbis.c"
+
+#define SAMPLES_TO_TEST 3000
+
+int test_count  [5] = { 5000, 3000, 2000, 50000, 50000 };
+int test_spacing[5] = {    1,  111, 3337,  7779, 72717 };
+
+int try_seeking(stb_vorbis *v, unsigned int pos, short *output, unsigned int num_samples)
+{
+   int count;
+   short samples[SAMPLES_TO_TEST*2];
+   assert(pos <= num_samples);
+
+   if (!stb_vorbis_seek(v, pos)) {
+      fprintf(stderr, "Seek to %u returned error from stb_vorbis\n", pos);
+      return 0;
+   }
+
+   count = stb_vorbis_get_samples_short_interleaved(v, 2, samples, SAMPLES_TO_TEST*2);
+
+   if (count > (int) (num_samples - pos)) {
+      fprintf(stderr, "Seek to %u allowed decoding %d samples when only %d should have been valid.\n",
+            pos, count, (int) (num_samples - pos));
+      return 0;
+   }
+
+   if (count < SAMPLES_TO_TEST && count < (int) (num_samples - pos)) {
+      fprintf(stderr, "Seek to %u only decoded %d samples of %d attempted when at least %d should have been valid.\n",
+         pos, count, SAMPLES_TO_TEST, num_samples - pos);
+      return 0;                      
+   }
+
+   if (0 != memcmp(samples, output + pos*2, count*2)) {
+      int k;
+      for (k=0; k < SAMPLES_TO_TEST*2; ++k) {
+         if (samples[k] != output[k]) {
+            fprintf(stderr, "Seek to %u produced incorrect samples starting at sample %u (short #%d in buffer).\n",
+                    pos, pos + (k/2), k);
+            break;
+         }
+      }
+      assert(k != SAMPLES_TO_TEST*2);
+      return 0;
+   }
+
+   return 1;
+}
+
+int main(int argc, char **argv)
+{
+   int num_chan, samprate;
+   int i, j, test, phase;
+   short *output;
+   if (argc == 1) {
+      fprintf(stderr, "Usage: vorbseek {vorbisfile} [{vorbisfile]*]\n");
+      fprintf(stderr, "Tests various seek offsets to make sure they're sample exact.\n");
+      return 0;
+   }
+
+   for (j=1; j < argc; ++j) {
+      unsigned int successes=0, attempts = 0;
+      unsigned int num_samples = stb_vorbis_decode_filename(argv[j], &num_chan, &samprate, &output);
+
+      if (num_samples == 0xffffffff) {
+         fprintf(stderr, "Error: couldn't open file or not vorbis file: %s\n", argv[j]);
+         goto fail;
+      }
+
+      if (num_chan != 2) {
+         fprintf(stderr, "vorbseek testing only works with files with 2 channels, %s has %d\n", argv[j], num_chan);
+         goto fail;
+      }
+
+      for (test=0; test < 5; ++test) {
+         int error;
+         stb_vorbis *v = stb_vorbis_open_filename(argv[j], &error, NULL);
+         if (v == NULL) {
+            fprintf(stderr, "Couldn't re-open %s for test #%d\n", argv[j], test);
+            goto fail;
+         }
+         for (phase=0; phase < 3; ++phase) {
+            unsigned int base = phase == 0 ? 0 : phase == 1 ? num_samples - test_count[test]*test_spacing[test] : num_samples/3;
+            for (i=0; i < test_count[test]; ++i) {
+               unsigned int pos = base + i*test_spacing[test];
+               if (pos > num_samples) // this also catches underflows
+                  continue;
+               successes += try_seeking(v, pos, output, num_samples);
+               attempts += 1;
+            }
+         }
+         stb_vorbis_close(v);
+      }
+      printf("%d of %d seeks failed in %s (%d samples)\n", attempts-successes, attempts, argv[j], num_samples);
+      free(output);
+   }
+   return 0;
+  fail:
+   return 1;
+}