Chunks

ValueInput.WriteToChunk('demo.chunk', 'fader');
ValueDisplay.ReadFromChunk('demo.chunk', 'fader');

////////////////////////////////////////////////////////////////////////////////
// Chunk Management Demo - demonstrates chunk subscriptions and read/write
// helpers. Use the controls to push a value to a chunk, read it back, and clear
// chunk items while observing callback notifications.
////////////////////////////////////////////////////////////////////////////////

const CHUNK_NAME      = 'demo.chunk';
const CHUNK_ITEM      = 'fader';
const CALLBACK_ID     = $01;

var
  WriteBtn      : TParameter;
  ReadBtn       : TParameter;
  ClearItemBtn  : TParameter;
  ClearChunkBtn : TParameter;
  ValueInput    : TParameter;
  ValueDisplay  : TParameter;
  InfoText      : TParameter;

procedure UpdateInfo(const msg: string);
begin
  InfoText.asString(msg);
end;

procedure PushToChunk;
begin
  ValueInput.WriteToChunk(CHUNK_NAME, CHUNK_ITEM);
  UpdateInfo('Value written to chunk "' + CHUNK_NAME + '" item "' + CHUNK_ITEM + '".');
end;

procedure PullFromChunk;
begin
  ValueDisplay.ReadFromChunk(CHUNK_NAME, CHUNK_ITEM);
  UpdateInfo('Value read from chunk "' + CHUNK_NAME + '" item "' + CHUNK_ITEM + '".');
end;

procedure Init;
begin
  ModuleColor($FF7E57C2);

  WriteBtn      := CreateParam('write chunk',  ptButton,    pioInput);
  ReadBtn       := CreateParam('read chunk',   ptButton,    pioInput);
  ClearItemBtn  := CreateParam('clear item',   ptButton,    pioInput);
  ClearChunkBtn := CreateParam('clear chunk',  ptButton,    pioInput);
  ValueInput    := CreateParam('value in',     ptDataFader, pioInput);
  ValueDisplay  := CreateParam('value out',    ptDataField, pioOutput);
  InfoText      := CreateParam('info',         ptTextField, pioOutput);

  ValueInput.Min(0);
  ValueInput.Max(1);
  ValueInput.AsFloat(0.5);

  ValueDisplay.Min(0);
  ValueDisplay.Max(1);

  UpdateInfo('Press "write chunk" to store the current value.');

  // Subscribe to chunk changes so the Callback gets triggered on updates.
  SubscribeChunk(CHUNK_NAME, CHUNK_ITEM, CALLBACK_ID, true);
end;

procedure Destroy;
begin
  // Unsubscribe and clear chunk data when this script is released.
  unSubscribeAll;
  ClearChunk(CHUNK_NAME);
end;

procedure Callback(N: integer);
begin
  if N = WriteBtn then
    PushToChunk;

  if N = ReadBtn then
    PullFromChunk;

  if N = ClearItemBtn then
  begin
    ClearChunkItem(CHUNK_NAME, CHUNK_ITEM);
    UpdateInfo('Chunk item "' + CHUNK_ITEM + '" cleared.');
    ValueDisplay.asFloat(0);
  end;

  if N = ClearChunkBtn then
  begin
    ClearChunk(CHUNK_NAME);
    UpdateInfo('Entire chunk "' + CHUNK_NAME + '" cleared.');
    ValueDisplay.asFloat(0);
  end;

  // Handle the chunk subscription callback (CALLBACK_ID).
  if N = CALLBACK_ID then
  begin
    ValueDisplay.ReadFromChunk(CHUNK_NAME, CHUNK_ITEM);
    UpdateInfo('Callback received for chunk update; value refreshed.');
  end;
end;

TParameter.WriteToChunk

procedure TParameter.ReadFromChunk (ChunkName,ItemName : string);

Copy parameter into a named chunk.

//write to a chunk
PROCEDURE PROCESS();                                          
BEGIN   
  clearChunk('MYCHUNK') // not mandatory, in any case the `item1` will be rewritten.
  input.WriteToChunk('MYCHUNK','item1');
END;      

TParameter.ReadFromChunk

procedure TParameter.WriteToChunk (ChunkName,ItemName : string);

Restores a parameter from a chunk entry.

//read a chunk
PROCEDURE PROCESS();                                          
BEGIN   
   output.ReadFromChunk('MYCHUNK','item2');
END;

ClearChunkItem

procedure ClearChunkItem(ChunkName, ItemName: string);

Clears a specific item within a chunk

ClearChunkItem('ArpState', 'notes');

ClearChunk

procedure ClearChunk(ChunkName: string);

Clear all data within a specified chunk.

ClearChunk('ArpState');

SubscribeChunk

procedure SubscribeChunk(ChunkName, ItemName: string; CallBackID: uint32; Immediate: boolean);

Registers a callback to receive notifications when a module alter a chunk. The script is informed of the change by sending a message in the callback procedure if ItemName is empty, the script will subscribe to any changes of the chunk (any item)

If immediate is set to TRUE the callback is called immediately after the changes occurs, and is done in the audio thread. Otherwise, it passes thru the main thread with a 25-50ms delay.

var output : TParameter; 

//INIT PROCEDURE
PROCEDURE INIT();
BEGIN    
  output:=CreateParam('out',ptDataFader,pioOutput);
  SubscribeChunk('QSDF','i1',$A01,true);
END;

//CALLBACK         
PROCEDURE CALLBACK(N:INTEGER);
BEGIN
  CASE N OF
   $A01: Begin     
          output.ReadFromChunk('QSDF','i1');
          End;
  End;//END MAIN CASE            
END;

UnSubscribeAll

procedure ClearChunk(ChunkName: string);

Cancels every chunk subscription.

Procedure Destroy;
   UnSubscribeAll;
End;

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