<?xml version="1.0"?>
<!DOCTYPE ladspa SYSTEM "ladspa-swh.dtd">
<?xml-stylesheet href="ladspa.css" type="text/css"?>

<ladspa>
  <global>
    <meta name="maker" value="Steve Harris &lt;steve@plugin.org.uk&gt;"/>
    <meta name="copyright" value="GPL"/>
    <code><![CDATA[
#include "ladspa-util.h"

#define MAX_BSIZE 1000

int partition(LADSPA_Data array[], int left, int right);

void q_sort(LADSPA_Data array[], int left, int right) {
	float pivot = partition(array, left, right);

	if (left < pivot) {
		q_sort(array, left, pivot-1);
	}
	if (right > pivot) {
		q_sort(array, pivot+1, right);
	}
}

int partition(LADSPA_Data array[], int left, int right) {
	float pivot = array[left];

	while (left < right) {
		while (array[right] >= pivot && left < right) {
			right--;
		}
		if (left != right) {
			array[left] = array[right];
			left++;
		}
		while (array[left] <= pivot && left < right) {
			left++;
		}
		if (left != right) {
			array[right] = array[left];
			right--;
		}
	}
	array[left] = pivot;

	return left;
}
    ]]></code>
  </global>

  <plugin label="sifter" id="1210" class="TimePlugin,DistortionPlugin">
    <name>Signal sifter</name>
    <p>Sorts and mixes blocks of the input signal to give a "bumpy ramp" effect.</p>
    <p>Certain types of input will produce silence on the output (mostly ones with only low frequency components).</p>
    <p>This is a very odd effect, and doesn't really have any music applications, but can produce some interesting noises.</p>

    <callback event="instantiate"><![CDATA[
      long i;
      float scla = (float)MAX_BSIZE * 0.5f;
      float sclb = (float)MAX_BSIZE;

      b1 = (LADSPA_Data *)calloc(MAX_BSIZE, sizeof(LADSPA_Data));
      b2 = (LADSPA_Data *)calloc(MAX_BSIZE, sizeof(LADSPA_Data));
      ob = (LADSPA_Data *)calloc(MAX_BSIZE, sizeof(LADSPA_Data));
      rc = (LADSPA_Data *)calloc(MAX_BSIZE, sizeof(LADSPA_Data));

      // Calculate raised cosine table, to build windowing function from
      rc[0] = cos(((0.0f - scla) / sclb) * M_PI);
      rc[0] *= rc[0];
      for (i=1; i<MAX_BSIZE / 2; i++) {
        rc[i] = cos((((float)i - scla) / sclb) * M_PI);
        rc[i] *= rc[i];
        rc[MAX_BSIZE - i] = rc[i];
      }
      rc[MAX_BSIZE / 2] = 1.0f;

      b1ptr = 0;
      b2ptr = 0;
    ]]></callback>

    <callback event="activate"><![CDATA[
      b1ptr = 0;
      b2ptr = 0;
      memset(b1, 0, MAX_BSIZE * sizeof(LADSPA_Data));
      memset(b2, 0, MAX_BSIZE * sizeof(LADSPA_Data));
      memset(ob, 0, MAX_BSIZE * sizeof(LADSPA_Data));
    ]]></callback>

    <callback event="cleanup"><![CDATA[
      free(plugin_data->b1);
      free(plugin_data->b2);
      free(plugin_data->ob);
      free(plugin_data->rc);
    ]]></callback>

    <callback event="run"><![CDATA[
unsigned long pos, i;
long bsize = f_round(LIMIT(size, 1, MAX_BSIZE));

for (pos = 0; pos < sample_count; pos++) {
	if (b1ptr >= bsize) {
		float wstep = (float)MAX_BSIZE / (float)b1ptr, wpos = 0.0f;

		q_sort(b1, 0, b1ptr);
		for (i=0; i<b1ptr; i++) {
			ob[i] += b1[i] * rc[f_round(wpos)];
			wpos += wstep;
		}
		b1ptr = 0;
		b2ptr = (bsize+1) / 2;
	}

	if (b2ptr >= bsize) {
		float wstep = (float)MAX_BSIZE / (float)b2ptr, wpos = 0.0f;
		int offset = (b2ptr+1)/2;

		q_sort(b2, 0, b2ptr);
		for (i=0; i<offset; i++) {
			ob[i + offset] += b2[i] * rc[f_round(wpos)];
			wpos += wstep;
		}
		for (; i<b2ptr; i++) {
			ob[i - offset] += b2[i] * rc[f_round(wpos)];
			wpos += wstep;
		}
		b2ptr = 0;
	}

	if (bsize < 2) {
		ob[b1ptr] = input[pos];
	}

	b1[b1ptr] = input[pos];
	b2[b2ptr] = input[pos];
	buffer_write(output[pos], ob[b1ptr]);
	ob[b1ptr] = 0.0f;
	b1ptr++;
	b2ptr++;
}

plugin_data->b1ptr = b1ptr;
plugin_data->b2ptr = b2ptr;
    ]]></callback>

    <port label="size" dir="input" type="control" hint="default_1">
      <name>Sift size</name>
      <range min="1" max="MAX_BSIZE"/>
    </port>

    <port label="input" dir="input" type="audio">
      <name>Input</name>
    </port>

    <port label="output" dir="output" type="audio">
      <name>Output</name>
    </port>

    <instance-data label="b1ptr" type="long"/>
    <instance-data label="b2ptr" type="long"/>
    <instance-data label="b1" type="LADSPA_Data *"/>
    <instance-data label="b2" type="LADSPA_Data *"/>
    <instance-data label="ob" type="LADSPA_Data *"/>
    <instance-data label="rc" type="LADSPA_Data *"/>

  </plugin>
</ladspa>