Add audio::mixer::max_length

libs/audio/include/psemek/audio/combine/mixer.hpp

@@ -15,6 +15,7 @@ namespace psemek::audio
 		virtual channel_ptr add(stream_ptr stream) = 0;
 
 		virtual std::size_t stream_count() const = 0;
+		virtual std::size_t max_length() const = 0;
 	};
 
 	using mixer_ptr = std::shared_ptr<mixer>;

libs/audio/source/combine/mixer.cpp

@@ -22,6 +22,8 @@ namespace psemek::audio
 				return stream_count_.load();
 			}
 
+			std::size_t max_length() const override;
+
 			std::size_t read(util::span<float> samples) override;
 
 			std::optional<std::size_t> length() const override
@@ -59,6 +61,17 @@ namespace psemek::audio
 			return result;
 		}
 
+		std::size_t mixer_impl::max_length() const
+		{
+			// TODO: safe access when the mixer is already playing?
+			std::size_t result = 0;
+			for (auto const & channel : new_channels_)
+				if (auto stream = channel->stream())
+					if (auto length = stream->length(); length && *length > result)
+						result = *length;
+			return result;
+		}
+
 		std::size_t mixer_impl::read(util::span<float> samples)
 		{
 			{

libs/audio/source/recorder.cpp

@@ -23,25 +23,26 @@ namespace psemek::audio
 
 			std::size_t request(std::size_t sample_count) override
 			{
-				std::size_t count = 0;
-
 				if (storage_.size() < samples_.size() + sample_count)
 				{
 					storage_.resize(std::max<std::size_t>(samples_.size() + sample_count, storage_.size() * 2));
 					samples_ = {storage_.data(), storage_.data() + samples_.size()};
 				}
 
+				std::size_t count = 0;
 				if (auto stream = channel_->stream())
 				{
 					count = stream->read({storage_.data() + samples_.size(), sample_count});
 					if (count < sample_count)
+					{
 						channel_->stop();
+					}
 				}
 
-				std::fill(storage_.data() + samples_.size() + count, storage_.data() + samples_.size() + sample_count, 0.f);
-				samples_ = {storage_.data(), storage_.data() + samples_.size() + sample_count};
+				std::fill(storage_.data() + samples_.size() + count, storage_.data() + samples_.size() + count, 0.f);
+				samples_ = {storage_.data(), storage_.data() + samples_.size() + count};
 
-				return sample_count;
+				return count;
 			}
 
 			util::span<float const> buffer() const override