Add truncate effect

libs/audio/include/psemek/audio/effect/truncate.hpp

@@ -0,0 +1,11 @@
+#pragma once
+
+#include <psemek/audio/stream.hpp>
+#include <psemek/audio/duration.hpp>
+
+namespace psemek::audio
+{
+
+	stream_ptr truncate(stream_ptr stream, duration length);
+
+}

libs/audio/source/effect/truncate.cpp

@@ -0,0 +1,47 @@
+#include <psemek/audio/effect/truncate.hpp>
+
+namespace psemek::audio
+{
+
+	namespace
+	{
+
+		struct truncate_impl
+			: stream
+		{
+			truncate_impl(stream_ptr stream, duration length)
+				: stream_(std::move(stream))
+				, length_(length)
+			{}
+
+			std::optional<std::size_t> length() const override
+			{
+				return length_.samples();
+			}
+
+			std::size_t read(float * data, std::size_t sample_count) override
+			{
+				auto played = stream_->played();
+				auto result = std::min<std::size_t>(length_.samples() - played, sample_count);
+				result = stream_->read(data, result);
+				return result;
+			}
+
+			std::size_t played() const override
+			{
+				return stream_->played();
+			}
+
+		private:
+			stream_ptr stream_;
+			duration length_;
+		};
+
+	}
+
+	stream_ptr truncate(stream_ptr stream, duration length)
+	{
+		return std::make_shared<truncate_impl>(std::move(stream), length);
+	}
+
+}