Implement mp3 support

libs/audio/CMakeLists.txt

@@ -1,7 +1,7 @@
 find_package(SDL2_mixer REQUIRED)
 
-file(GLOB_RECURSE PSEMEK_AUDIO_HEADERS RELATIVE "${CMAKE_CURRENT_SOURCE_DIR}" "include/*.hpp")
-file(GLOB_RECURSE PSEMEK_AUDIO_SOURCES RELATIVE "${CMAKE_CURRENT_SOURCE_DIR}" "source/*.cpp")
+file(GLOB_RECURSE PSEMEK_AUDIO_HEADERS RELATIVE "${CMAKE_CURRENT_SOURCE_DIR}" "include/*.hpp" "include/*.h")
+file(GLOB_RECURSE PSEMEK_AUDIO_SOURCES RELATIVE "${CMAKE_CURRENT_SOURCE_DIR}" "source/*.cpp" "source/*.c")
 
 psemek_add_library(psemek-audio ${PSEMEK_AUDIO_HEADERS} ${PSEMEK_AUDIO_SOURCES})
 target_include_directories(psemek-audio PUBLIC "${CMAKE_CURRENT_SOURCE_DIR}/include")

libs/audio/include/psemek/audio/minimp3/options.h

@@ -0,0 +1,4 @@
+#pragma once
+
+#define MINIMP3_NO_SIMD
+#define MINIMP3_FLOAT_OUTPUT

libs/audio/include/psemek/audio/track.hpp

@@ -25,4 +25,7 @@ namespace psemek::audio
 	track_ptr load_wav(util::span<char const> data);
 	track_ptr load_wav(std::vector<char> const & data);
 
+	track_ptr load_mp3(util::span<char const> data);
+	track_ptr load_mp3(std::vector<char> data);
+
 }

libs/audio/source/minimp3/minimp3.c

@@ -0,0 +1,3 @@
+#define MINIMP3_IMPLEMENTATION
+#include <psemek/audio/minimp3/options.h>
+#include <psemek/audio/minimp3/minimp3.h>

libs/audio/source/track_mp3.cpp

@@ -0,0 +1,133 @@
+#include <psemek/audio/track.hpp>
+
+#include <psemek/audio/minimp3/options.h>
+#include <psemek/audio/minimp3/minimp3.h>
+
+#include <atomic>
+
+namespace psemek::audio
+{
+
+	namespace
+	{
+
+		struct mp3_data_holder
+		{
+			std::vector<char> storage;
+			util::span<char const> data;
+
+			mp3_data_holder(std::vector<char> storage)
+				: storage(std::move(storage))
+				, data(this->storage)
+			{}
+
+			mp3_data_holder(util::span<char const> data)
+				: data(data)
+			{}
+		};
+
+		struct mp3_stream_impl
+			: stream
+		{
+			mp3_stream_impl(std::shared_ptr<mp3_data_holder> data)
+				: data_(std::move(data))
+				, buffer_(MINIMP3_MAX_SAMPLES_PER_FRAME)
+			{
+				mp3dec_init(&decoder_);
+			}
+
+			std::optional<std::size_t> length() const override
+			{
+				return std::nullopt;
+			}
+
+			std::size_t read(float * data, std::size_t sample_count) override
+			{
+				auto input = reinterpret_cast<std::uint8_t const *>(data_->data.data());
+
+				std::size_t result = 0;
+				while (result < sample_count)
+				{
+					if (buffer_pos_ < buffer_size_)
+					{
+						std::size_t size = std::min(buffer_size_ - buffer_pos_, sample_count - result);
+						std::copy(buffer_.data() + buffer_pos_, buffer_.data() + buffer_pos_ + size, data + result);
+						buffer_pos_ += size;
+						result += size;
+					}
+					else
+					{
+						mp3dec_frame_info_t frame_info;
+						buffer_size_ = mp3dec_decode_frame(&decoder_, input + read_bytes_, data_->data.size() - read_bytes_, buffer_.data(), &frame_info);
+						buffer_pos_ = 0;
+						read_bytes_ += frame_info.frame_bytes;
+
+						if (frame_info.channels == 1)
+						{
+							for (std::size_t i = buffer_size_ * 2; i > 0;)
+							{
+								i -= 2;
+								buffer_[i + 0] = buffer_[i / 2];
+								buffer_[i + 1] = buffer_[i / 2];
+							}
+							buffer_size_ *= 2;
+						}
+
+						if (frame_info.frame_bytes == 0)
+							break;
+					}
+				}
+
+				return result;
+			}
+
+			std::size_t played() const override
+			{
+				return played_.load();
+			}
+
+		private:
+			std::shared_ptr<mp3_data_holder> data_;
+			std::size_t read_bytes_{0};
+
+			mp3dec_t decoder_;
+			std::vector<float> buffer_;
+			std::size_t buffer_pos_{0};
+			std::size_t buffer_size_{0};
+			std::atomic<std::size_t> played_{0};
+		};
+
+		struct mp3_track_impl
+			: track
+		{
+			mp3_track_impl(std::shared_ptr<mp3_data_holder> data)
+				: data_(std::move(data))
+			{}
+
+			stream_ptr stream() const override
+			{
+				return std::make_shared<mp3_stream_impl>(data_);
+			}
+
+			std::optional<std::size_t> length() const override
+			{
+				return std::nullopt;
+			}
+
+		private:
+			std::shared_ptr<mp3_data_holder> data_;
+		};
+
+	}
+
+	track_ptr load_mp3(util::span<char const> data)
+	{
+		return std::make_shared<mp3_track_impl>(std::make_shared<mp3_data_holder>(data));
+	}
+
+	track_ptr load_mp3(std::vector<char> data)
+	{
+		return std::make_shared<mp3_track_impl>(std::make_shared<mp3_data_holder>(std::move(data)));
+	}
+
+}