73 lines
1.5 KiB
C++
73 lines
1.5 KiB
C++
// SPDX-License-Identifier: GPL-2.0-or-later
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// Copyright The Music Player Daemon Project
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#ifndef MPD_MUSIC_BUFFER_HXX
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#define MPD_MUSIC_BUFFER_HXX
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#include "MusicChunk.hxx"
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#include "MusicChunkPtr.hxx"
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#include "util/SliceBuffer.hxx"
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#include "thread/Mutex.hxx"
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/**
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* An allocator for #MusicChunk objects.
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*/
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class MusicBuffer {
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/** a mutex which protects #buffer */
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mutable Mutex mutex;
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SliceBuffer<MusicChunk> buffer;
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public:
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/**
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* Creates a new #MusicBuffer object.
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*
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* @param num_chunks the number of #MusicChunk reserved in
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* this buffer
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*/
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explicit MusicBuffer(unsigned num_chunks);
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#ifndef NDEBUG
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/**
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* Check whether the buffer is empty. This call is not
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* protected with the mutex, and may only be used while this
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* object is inaccessible to other threads.
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*/
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bool IsEmptyUnsafe() const {
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return buffer.empty();
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}
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#endif
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bool IsFull() const noexcept {
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const std::scoped_lock protect{mutex};
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return buffer.IsFull();
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}
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/**
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* Returns the total number of reserved chunks in this buffer. This
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* is the same value which was passed to the constructor
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* music_buffer_new().
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*/
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[[gnu::pure]]
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unsigned GetSize() const noexcept {
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return buffer.GetCapacity();
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}
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/**
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* Allocates a chunk from the buffer. When it is not used anymore,
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* call Return().
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*
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* @return an empty chunk or nullptr if there are no chunks
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* available
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*/
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MusicChunkPtr Allocate() noexcept;
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/**
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* Returns a chunk to the buffer. It can be reused by
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* Allocate() then.
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*/
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void Return(MusicChunk *chunk) noexcept;
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};
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#endif
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