--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gst_plugins_base/gst/audioresample/resample_functable.c	Wed Sep 01 12:16:41 2010 +0100
@@ -0,0 +1,279 @@
+/* Resampling library
+ * Copyright (C) <2001> David A. Schleef <ds@schleef.org>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#ifndef __SYMBIAN32__
+#include <config.h>
+#else
+#include "config.h"
+#endif
+#endif
+
+
+#include <string.h>
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <limits.h>
+#ifndef __SYMBIAN32__
+#include <liboil/liboil.h>
+#endif
+
+#include "resample.h"
+#include "buffer.h"
+#include "debug.h"
+
+static void
+func_sinc (double *fx, double *dfx, double x, void *closure)
+{
+  //double scale = *(double *)closure;
+  double scale = M_PI;
+
+  if (x == 0) {
+    *fx = 1;
+    *dfx = 0;
+    return;
+  }
+
+  x *= scale;
+  *fx = sin (x) / x;
+  *dfx = scale * (cos (x) - sin (x) / x) / x;
+}
+
+static void
+func_hanning (double *fx, double *dfx, double x, void *closure)
+{
+  double width = *(double *) closure;
+
+  if (x < width && x > -width) {
+    x /= width;
+    *fx = (1 - x * x) * (1 - x * x);
+    *dfx = -2 * 2 * x / width * (1 - x * x);
+  } else {
+    *fx = 0;
+    *dfx = 0;
+  }
+}
+
+#if 0
+static double
+resample_sinc_window (double x, double halfwidth, double scale)
+{
+  double y;
+
+  if (x == 0)
+    return 1.0;
+  if (x < -halfwidth || x > halfwidth)
+    return 0.0;
+
+  y = sin (x * M_PI * scale) / (x * M_PI * scale) * scale;
+
+  x /= halfwidth;
+  y *= (1 - x * x) * (1 - x * x);
+
+  return y;
+}
+#endif
+
+#if 0
+static void
+functable_test (Functable * ft, double halfwidth)
+{
+  int i;
+  double x;
+
+  for (i = 0; i < 100; i++) {
+    x = i * 0.1;
+    printf ("%d %g %g\n", i, resample_sinc_window (x, halfwidth, 1.0),
+        functable_evaluate (ft, x));
+  }
+  exit (0);
+
+}
+#endif
+
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+void
+resample_scale_functable (ResampleState * r)
+{
+  if (r->need_reinit) {
+    double hanning_width;
+
+    RESAMPLE_DEBUG ("sample size %d", r->sample_size);
+
+    if (r->buffer)
+      free (r->buffer);
+    r->buffer_len = r->sample_size * r->filter_length;
+    r->buffer = malloc (r->buffer_len);
+    memset (r->buffer, 0, r->buffer_len);
+
+    r->i_inc = r->o_rate / r->i_rate;
+    r->o_inc = r->i_rate / r->o_rate;
+    RESAMPLE_DEBUG ("i_inc %g o_inc %g", r->i_inc, r->o_inc);
+
+    r->i_start = -r->i_inc * r->filter_length;
+
+    if (r->ft) {
+      functable_free (r->ft);
+    }
+    r->ft = functable_new ();
+    functable_set_length (r->ft, r->filter_length * 16);
+    functable_set_offset (r->ft, -r->filter_length / 2);
+    functable_set_multiplier (r->ft, 1 / 16.0);
+
+    hanning_width = r->filter_length / 2;
+    functable_calculate (r->ft, func_sinc, NULL);
+    functable_calculate_multiply (r->ft, func_hanning, &hanning_width);
+
+    //functable_test(r->ft, 0.5 * r->filter_length);
+#if 0
+    if (r->i_inc < 1.0) {
+      r->sinc_scale = r->i_inc;
+      if (r->sinc_scale == 0.5) {
+        /* strange things happen at integer multiples */
+        r->sinc_scale = 1.0;
+      }
+    } else {
+      r->sinc_scale = 1.0;
+    }
+#else
+    r->sinc_scale = 1.0;
+#endif
+
+    r->need_reinit = 0;
+  }
+
+  while (r->o_size > 0) {
+    double midpoint;
+    int i;
+    int j;
+
+    RESAMPLE_DEBUG ("i_start %g", r->i_start);
+    midpoint = r->i_start + (r->filter_length - 1) * 0.5 * r->i_inc;
+    if (midpoint > 0.5 * r->i_inc) {
+      RESAMPLE_ERROR ("inconsistent state");
+    }
+    while (midpoint < -0.5 * r->i_inc) {
+      AudioresampleBuffer *buffer;
+
+      buffer = audioresample_buffer_queue_pull (r->queue, r->sample_size);
+      if (buffer == NULL) {
+        RESAMPLE_ERROR ("buffer_queue_pull returned NULL");
+        return;
+      }
+
+      r->i_start += r->i_inc;
+      RESAMPLE_DEBUG ("pulling (i_start = %g)", r->i_start);
+
+      midpoint += r->i_inc;
+      memmove (r->buffer, r->buffer + r->sample_size,
+          r->buffer_len - r->sample_size);
+
+      memcpy (r->buffer + r->buffer_len - r->sample_size, buffer->data,
+          r->sample_size);
+      audioresample_buffer_unref (buffer);
+    }
+
+    switch (r->format) {
+      case RESAMPLE_FORMAT_S16:
+        for (i = 0; i < r->n_channels; i++) {
+          double acc = 0;
+          double offset;
+          double x;
+
+          for (j = 0; j < r->filter_length; j++) {
+            offset = (r->i_start + j * r->i_inc) * r->o_inc;
+            x = *(int16_t *) (r->buffer + i * sizeof (int16_t) +
+                j * r->sample_size);
+            acc += functable_evaluate (r->ft, offset) * x;
+            //acc += resample_sinc_window (offset, r->filter_length * 0.5, r->sinc_scale) * x;
+          }
+          if (acc < -32768.0)
+            acc = -32768.0;
+          if (acc > 32767.0)
+            acc = 32767.0;
+
+          *(int16_t *) (r->o_buf + i * sizeof (int16_t)) = rint (acc);
+        }
+        break;
+      case RESAMPLE_FORMAT_S32:
+        for (i = 0; i < r->n_channels; i++) {
+          double acc = 0;
+          double offset;
+          double x;
+
+          for (j = 0; j < r->filter_length; j++) {
+            offset = (r->i_start + j * r->i_inc) * r->o_inc;
+            x = *(int32_t *) (r->buffer + i * sizeof (int32_t) +
+                j * r->sample_size);
+            acc += functable_evaluate (r->ft, offset) * x;
+            //acc += resample_sinc_window (offset, r->filter_length * 0.5, r->sinc_scale) * x;
+          }
+          if (acc < -2147483648.0)
+            acc = -2147483648.0;
+          if (acc > 2147483647.0)
+            acc = 2147483647.0;
+
+          *(int32_t *) (r->o_buf + i * sizeof (int32_t)) = rint (acc);
+        }
+        break;
+      case RESAMPLE_FORMAT_F32:
+        for (i = 0; i < r->n_channels; i++) {
+          double acc = 0;
+          double offset;
+          double x;
+
+          for (j = 0; j < r->filter_length; j++) {
+            offset = (r->i_start + j * r->i_inc) * r->o_inc;
+            x = *(float *) (r->buffer + i * sizeof (float) +
+                j * r->sample_size);
+            acc += functable_evaluate (r->ft, offset) * x;
+            //acc += resample_sinc_window (offset, r->filter_length * 0.5, r->sinc_scale) * x;
+          }
+
+          *(float *) (r->o_buf + i * sizeof (float)) = acc;
+        }
+        break;
+      case RESAMPLE_FORMAT_F64:
+        for (i = 0; i < r->n_channels; i++) {
+          double acc = 0;
+          double offset;
+          double x;
+
+          for (j = 0; j < r->filter_length; j++) {
+            offset = (r->i_start + j * r->i_inc) * r->o_inc;
+            x = *(double *) (r->buffer + i * sizeof (double) +
+                j * r->sample_size);
+            acc += functable_evaluate (r->ft, offset) * x;
+            //acc += resample_sinc_window (offset, r->filter_length * 0.5, r->sinc_scale) * x;
+          }
+
+          *(double *) (r->o_buf + i * sizeof (double)) = acc;
+        }
+        break;
+    }
+
+    r->i_start -= 1.0;
+    r->o_buf += r->sample_size;
+    r->o_size -= r->sample_size;
+  }
+
+}