audio subsystem replacement: openal audio renderer and buffer class, removed deprecated files

audio.h

@@ -0,0 +1,72 @@
+/*
+This Source Code Form is subject to the
+terms of the Mozilla Public License, v.
+2.0. If a copy of the MPL was not
+distributed with this file, You can
+obtain one at
+http://mozilla.org/MPL/2.0/.
+*/
+
+#pragma once
+
+#include "al.h"
+#include "alc.h"
+
+namespace audio {
+
+ALuint const null_resource { ~ALuint{ 0 } };
+
+struct openal_buffer {
+// members
+    ALuint id { null_resource }; // associated AL resource
+    unsigned int rate { 0 }; // sample rate of the data
+    std::string name;
+// constructors
+    openal_buffer() = default;
+    explicit openal_buffer( std::string const &Filename );
+
+private:
+// methods
+    // mix specified number of interleaved multi-channel data, down to mono
+    void
+        narrow_to_mono( std::uint16_t const Channelcount );
+// members
+    std::vector<std::int16_t> data; // audio data
+};
+
+using buffer_handle = std::size_t;
+
+class buffer_manager {
+
+public:
+// constructors
+    buffer_manager() { m_buffers.emplace_back( openal_buffer() ); } // empty bindings for null buffer
+// destructor
+    ~buffer_manager();
+// methods
+    // creates buffer object out of data stored in specified file. returns: handle to the buffer or null_handle if creation failed
+    buffer_handle
+        create( std::string const &Filename );
+
+private:
+// types
+    using buffer_sequence = std::vector<openal_buffer>;
+    using index_map = std::unordered_map<std::string, std::size_t>;
+// methods
+    // places in the bank a buffer containing data stored in specified file. returns: handle to the buffer
+    buffer_handle
+        emplace( std::string Filename );
+    // checks whether specified buffer is in the buffer bank. returns: buffer handle, or null_handle.
+    buffer_handle
+        find_buffer( std::string const &Buffername ) const;
+    // checks whether specified file exists. returns: name of the located file, or empty string.
+    std::string
+        find_file( std::string const &Filename ) const;
+// members
+    buffer_sequence m_buffers;
+    index_map m_buffermappings;
+};
+
+} // audio
+
+//---------------------------------------------------------------------------