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

<ladspa>
  <global>
    <meta name="maker" value="Jesse Chappell &lt;jesse at essej dot net&gt;"/>
    <meta name="copyright" value="GPL"/>
    <meta name="properties" value="HARD_RT_CAPABLE"/>
    <code><![CDATA[
      #include "ladspa-util.h"
      #include <stdio.h>

      #define MIN(a,b) ((a) < (b) ? (a) : (b))
      #define CALC_DELAY(delaytime) \
        (f_clamp (delaytime * sample_rate, 1.f, (float)(buffer_size + 1)))

    ]]></code>
  </global>


  <plugin label="revdelay" id="1605" class="DelayPlugin">
    <name>Reverse Delay (5s max)</name>
     <p> A reverse delay not really modelled on any existing one.  You'll want to set
         the Crossfade Samples parameter to something reasonably small (but more than 20)
         for most applications, but you can try larger values if you start getting clicking.
    </p>
    
    <callback event="instantiate"><![CDATA[
      sample_rate = s_rate;
      buffer_size = 0;
      delay_samples = 0;
      last_delay_time = 0;
      write_phase = 0;
    ]]></callback>
    
    <callback event="activate"><![CDATA[
      unsigned int size;

      size = sample_rate * 5 * 2; /* 5 second maximum */
        
      /* calloc sets the buffer to zero. */
      buffer = calloc(size, sizeof(LADSPA_Data));

      buffer_size = size;
      write_phase = 0;
      delay_samples = 0;
    ]]></callback>
    
    <callback event="cleanup"><![CDATA[
      free(plugin_data->buffer);
    ]]></callback>
    
    <callback event="run"><![CDATA[
      int i;
      unsigned long delay2;
      float dry = DB_CO(dry_level);
      float wet = DB_CO(wet_level);
      float fadescale;
      unsigned long xfadesamp = xfade_samp;

      if (write_phase == 0) {
        plugin_data->last_delay_time = delay_time;
        plugin_data->delay_samples = delay_samples = CALC_DELAY (delay_time);
      }

      if (delay_time == last_delay_time) {
        long idelay_samples = (long)delay_samples;
        delay2 = idelay_samples * 2;

        if (xfadesamp > idelay_samples) {
            /* force it to half */
            xfadesamp = idelay_samples / 2;
        }

        for (i=0; i<sample_count; i++) {
          long read_phase = delay2 - write_phase;
          LADSPA_Data read;
          LADSPA_Data insamp;

          insamp = in[i];
          read =  (wet * buffer[read_phase]) + (dry * insamp);

          if ( (write_phase % idelay_samples) < xfadesamp) {
            fadescale = (write_phase % idelay_samples) / (1.0 * xfadesamp);
          }
          else if ((write_phase % idelay_samples) > (idelay_samples - xfadesamp)) {
            fadescale = (idelay_samples - (write_phase % idelay_samples)) / (1.0 * xfadesamp);
          }
          else {
            fadescale = 1.0;
          }

          buffer[write_phase] = fadescale * (insamp + (feedback * read)); 
	  buffer[write_phase] = flush_to_zero(buffer[write_phase]);
                  
	  buffer_write(out[i], read);
          write_phase = (write_phase + 1) % delay2;
        }
      } else {
        float next_delay_samples = CALC_DELAY (delay_time);
        float delay_samples_slope = (next_delay_samples - delay_samples) / sample_count;

        for (i=0; i<sample_count; i++) {
          long read_phase, idelay_samples;
          LADSPA_Data frac, read;
          LADSPA_Data insamp;
          insamp = in[i];

          delay_samples += delay_samples_slope;
          delay2 = (long) (delay_samples * 2);
          write_phase = (write_phase + 1) % delay2;

          read_phase = delay2 - write_phase;
          idelay_samples = (long)delay_samples;
          frac = delay_samples - idelay_samples;
          read = wet * buffer[read_phase]   + (dry * insamp);

          if ((write_phase % idelay_samples) < xfade_samp) {
            fadescale = (write_phase % idelay_samples) / (1.0 * xfade_samp);
          }
          else if ((write_phase % idelay_samples) > (idelay_samples - xfade_samp)) {
            fadescale = (idelay_samples - (write_phase % idelay_samples)) / (1.0 * xfade_samp);
          }
          else {
            fadescale = 1.0;
          }

          buffer[write_phase] = fadescale * (insamp + (feedback * read)); 
	  buffer[write_phase] = flush_to_zero(buffer[write_phase]);

	  buffer_write(out[i], read);
        }

        plugin_data->last_delay_time = delay_time;
        plugin_data->delay_samples = delay_samples;
      }
      
      plugin_data->write_phase = write_phase;
    ]]></callback>

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

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

    <port label="delay_time" dir="input" type="control" hint="default_0">
      <name>Delay Time (s)</name>
      <range min="0" max="5.0"/>
    </port>

    <port label="dry_level" dir="input" type="control" hint="default_0">
      <name>Dry Level (dB)</name>
      <p>Controls the level of the dry input signal in dB's.</p>
      <range min="-70" max="0"/>
    </port>

    <port label="wet_level" dir="input" type="control" hint="default_0">
      <name>Wet Level (dB)</name>
      <p>Controls the level of the delayed signal in dB's.</p>
      <range min="-70" max="0"/>
    </port>

    <port label="feedback" dir="input" type="control" hint="default_0">
      <name>Feedback</name>
      <range min="0" max="1"/>
    </port>

    <port label="xfade_samp" dir="input" type="control" hint="default_low,integer">
      <name>Crossfade samples</name>
      <range min="0" max="5000"/>
    </port>


    <instance-data label="buffer" type="LADSPA_Data *" />
    <instance-data label="buffer_size" type="unsigned int" />
    <instance-data label="sample_rate" type="unsigned int" />
    <instance-data label="delay_samples" type="LADSPA_Data" />
    <instance-data label="write_phase" type="long" />
    <instance-data label="last_delay_time" type="LADSPA_Data" />

  </plugin>
</ladspa>

