/* * Copyright 2003-2018 The Music Player Daemon Project * http://www.musicpd.org * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ #ifndef MPD_MUSIC_BUFFER_HXX #define MPD_MUSIC_BUFFER_HXX #include "MusicChunkPtr.hxx" #include "util/SliceBuffer.hxx" #include "thread/Mutex.hxx" /** * An allocator for #MusicChunk objects. */ class MusicBuffer { /** a mutex which protects #buffer */ Mutex mutex; SliceBuffer buffer; public: /** * Creates a new #MusicBuffer object. * * @param num_chunks the number of #MusicChunk reserved in * this buffer */ explicit MusicBuffer(unsigned num_chunks); #ifndef NDEBUG /** * Check whether the buffer is empty. This call is not * protected with the mutex, and may only be used while this * object is inaccessible to other threads. */ bool IsEmptyUnsafe() const { return buffer.empty(); } #endif /** * Returns the total number of reserved chunks in this buffer. This * is the same value which was passed to the constructor * music_buffer_new(). */ gcc_pure unsigned GetSize() const noexcept { return buffer.GetCapacity(); } /** * Allocates a chunk from the buffer. When it is not used anymore, * call Return(). * * @return an empty chunk or nullptr if there are no chunks * available */ MusicChunkPtr Allocate() noexcept; /** * Returns a chunk to the buffer. It can be reused by * Allocate() then. */ void Return(MusicChunk *chunk) noexcept; }; #endif