Convert default resampler from libresample to libsoxr.

lib-src/libsoxr/examples/2b-stream-with-input-fn.c

@@ -0,0 +1,66 @@
+/* SoX Resampler Library      Copyright (c) 2007-12 robs@users.sourceforge.net
+ * Licence for this file: LGPL v2.1                  See LICENCE for details. */
+
+/* Example 2b: resample a raw, single-channel, floating-point data stream from
+ * stdin to stdout.  The application provides an input function, called on
+ * demand by libsoxr, in response to calls to soxr_output().
+ *
+ * Arguments are: INPUT-RATE OUTPUT-RATE
+ */
+
+#include "util.h"
+#include <soxr.h>
+
+
+
+static size_t input_fn(
+    void * p,           /* Generic pointer to any state variables neded here. */
+    soxr_cbuf_t * buf,            /* To tell the resampler where the data is. */
+    size_t requested_len)                          /* In samples per channel. */
+{
+  static float * ibuf;    /* Static context; this could be changed using `p'. */
+  size_t actual;
+
+  /* Allocate the input buffer memory; check for errors: */
+  *buf = ibuf = realloc(ibuf, sizeof(float) * requested_len);
+  if (!ibuf)
+    return 0;                           /* Indicate failure (*buf is also 0). */
+
+  /* Read samples from the input stream; check for errors: */
+  actual = fread(ibuf, sizeof(float), requested_len, stdin);
+  if (!actual && ferror(stdin))
+    *buf = 0;                         /* Indicate failure (actual is also 0). */
+
+  return actual;
+  (void)p;                                       /* Not used in this example. */
+}
+
+
+
+int main(int argc, char const * arg[])
+{
+  double irate = argc > 1? atof(arg[1]) : 44100.;
+  double orate = argc > 2? atof(arg[2]) : 96000.;
+
+  soxr_error_t error;
+  soxr_t resampler = soxr_create(irate, orate, 1, &error, 0, 0, 0);
+  if (!error)                        /* Register input_fn with the resampler: */
+    error = soxr_set_input_fn(resampler, input_fn, 0);
+
+  STD_STDIO;
+  if (!error) {                         /* If all is good, run the resampler: */
+    #define olen 1000
+    float resampled[olen];
+    size_t actual;
+                                                       /* Resample in blocks: */
+    do actual = soxr_output(resampler, resampled, olen);
+    while (fwrite(resampled, sizeof(float), actual, stdout));
+
+    error = soxr_error(resampler);    /* Note: before deleting the resampler! */
+    soxr_delete(resampler);
+  }
+                                                              /* Diagnostics: */
+  fprintf(stderr, "resampler: %s; I/O: %s\n",
+      soxr_strerror(error), errno? strerror(errno) : "no error");
+  return error || errno;
+}