Pascal API for VAD (#1249)

pascal-api-examples/vad/circular_buffer.pas

@@ -0,0 +1,106 @@
+{ Copyright (c)  2024  Xiaomi Corporation }
+program circular_buffer;
+{
+This file shows how to use the CircularBuffer API of sherpa-onnx
+}
+
+{$mode objfpc}
+{$ASSERTIONS ON}
+
+uses
+  sherpa_onnx;
+
+var
+  Buffer: TSherpaOnnxCircularBuffer;
+  Samples: TSherpaOnnxSamplesArray;
+begin
+  {The initial capacity is 5. It will be resized automatically if needed.}
+  Buffer := TSherpaOnnxCircularBuffer.Create(5);
+  Assert(Buffer.Size = 0);
+  Assert(Buffer.Head = 0);
+  Buffer.Push([0, 10, 20]);
+
+  {Push() changes Size. Head is not changed.}
+  Assert(Buffer.Size = 3);
+  Assert(Buffer.Head = 0);
+
+  Samples := Buffer.Get(0, 1);
+  Assert(Length(Samples) = 1);
+  Assert(Samples[0] = 0);
+
+  { Get() does not change Size or Head}
+  Assert(Buffer.Size = 3);
+  Assert(Buffer.Head = 0);
+
+  Samples := Buffer.Get(0, 2);
+  Assert(Length(Samples) = 2);
+  Assert(Samples[0] = 0);
+  Assert(Samples[1] = 10);
+
+  { The buffer will be resized since its initial capacity is 5 but we have
+    pushed 7 elements into it.
+
+    No data is lost during the resize.
+  }
+  Buffer.Push([30, 40, 50, 60]);
+
+  Assert(Buffer.Size = 7); {There are now 7 elements}
+  Assert(Buffer.Head = 0);
+
+  {Remove the first 4 elements}
+  Buffer.Pop(4);
+
+  Assert(Buffer.Size = 3); {There are only 3 elements left}
+  Assert(Buffer.Head = 4);
+
+  Samples := Buffer.Get(Buffer.Head, 2);
+  Assert(Length(Samples) = 2);
+  Assert(Samples[0] = 40);
+  Assert(Samples[1] = 50);
+
+  Buffer.Pop(1);
+
+  Assert(Buffer.Size = 2); {There are only 2 elements left}
+  Assert(Buffer.Head = 5);
+
+  Samples := Buffer.Get(Buffer.Head, 2);
+  Assert(Length(Samples) = 2);
+  Assert(Samples[0] = 50);
+  Assert(Samples[1] = 60);
+
+  Buffer.Pop(2);
+  Assert(Buffer.Size = 0); {There are no elements left}
+  Assert(Buffer.Head = 7);
+
+  Buffer.Push([100, 200, 300, 400, 500]);
+  Assert(Buffer.Size = 5);
+  Assert(Buffer.Head = 7);
+
+  Buffer.Pop(4);
+  Assert(Buffer.Size = 1);
+
+  {Head can be larger than the Capacity!
+   This is what circular means. It points to Buffer.Head / Capacity.
+  }
+  Assert(Buffer.Head = 11);
+  Buffer.Push([600, 700]);
+
+  Assert(Buffer.Size = 3);
+  Assert(Buffer.Head = 11);
+
+  Samples := Buffer.Get(Buffer.Head, 3);
+  Assert(Length(Samples) = 3);
+  Assert(Samples[0] = 500);
+  Assert(Samples[1] = 600);
+  Assert(Samples[2] = 700);
+
+  Buffer.Pop(3);
+  Assert(Buffer.Size = 0);
+  Assert(Buffer.Head = 14);
+
+  Buffer.Reset();
+
+  Assert(Buffer.Size = 0);
+  Assert(Buffer.Head = 0);
+end.
+