RingBuffer: initial commit
Implements a ring buffer class for LMMS, which is designed to be flexible, efficient and thread-safe. Due to flexible design, it supports various methods of operation: - set delays/sizes in absolute frame values, ignoring samplerate - set delays/sizes in milliseconds with samplerate-awareness - multiple inputs -> single output - single input -> multiple outputs Efficiency is achieved by working in buffers and using memcpy/memset for audio operations, except when additive mixing is needed: then MixHelpers are used Thread-safety is guaranteed with QMutex
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Vesa
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include/RingBuffer.h
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include/RingBuffer.h
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/*
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* RingBuffer.h - an effective, thread-safe and flexible implementation of a ringbuffer for LMMS
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*
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* Copyright (c) 2014 Vesa Kivimäki
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* Copyright (c) 2005-2014 Tobias Doerffel <tobydox/at/users.sourceforge.net>
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*
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* This file is part of Linux MultiMedia Studio - http://lmms.sourceforge.net
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program (see COPYING); if not, write to the
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* Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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* Boston, MA 02110-1301 USA.
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*
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*/
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#ifndef RINGBUFFER_H
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#define RINGBUFFER_H
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#include <QMutex>
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#include <QObject>
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#include "lmms_basics.h"
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#include "lmms_math.h"
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class RingBuffer : public QObject
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{
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Q_OBJECT
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public:
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/** \brief Constructs a ringbuffer of specified size, will not care about samplerate changes
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* \param size The size of the buffer in frames. The actual size will be size + period size
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*/
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RingBuffer( f_cnt_t size );
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/** \brief Constructs a ringbuffer of specified samplerate-dependent size, which will be updated when samplerate changes
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* \param size The size of the buffer in milliseconds. The actual size will be size + period size
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*/
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RingBuffer( float size );
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virtual ~RingBuffer();
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// thread safety functions - for internal use only, unless you know what you're doing!
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inline void lock()
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{
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m_ringBufferMutex.lock();
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}
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inline void unlock()
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{
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m_ringBufferMutex.unlock();
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}
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////////////////////////////////////
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// Provided functions //
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////////////////////////////////////
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// utility functions
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/** \brief Clears the ringbuffer of any data and resets the position to 0
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*/
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void reset();
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/** \brief Changes the size of the ringbuffer. Clears all data.
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* \param size New size in frames
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*/
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void changeSize( f_cnt_t size );
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/** \brief Changes the size of the ringbuffer. Clears all data.
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* \param size New size in milliseconds
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*/
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void changeSize( float size );
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/** \brief Sets whether the ringbuffer size is adjusted for samplerate when samplerate changes
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* \param b True if samplerate should affect buffer size
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*/
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void setSamplerateAware( bool b );
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// position adjustment functions
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/** \brief Advances the position by one period
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*/
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void advance();
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/** \brief Moves position forwards/backwards by an amount of frames
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* \param amount Number of frames to move, may be negative
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*/
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void movePosition( f_cnt_t amount );
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/** \brief Moves position forwards/backwards by an amount of milliseconds
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* \param amount Number of milliseconds to move, may be negative
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*/
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void movePosition( float amount );
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// read functions
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/** \brief Destructively reads a period-sized buffer from the current position, writes it
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* to a specified destination, and advances the position by one period
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* \param dst Destination pointer
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*/
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void pop( sampleFrame * dst );
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// note: ringbuffer position is unaffected by all other read functions beside pop()
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/** \brief Reads a period-sized buffer from the ringbuffer and writes it to a specified destination
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* \param dst Destination pointer
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* \param offset Offset in frames against current position, may be negative
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*/
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void read( sampleFrame * dst, f_cnt_t offset=0 );
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/** \brief Reads a period-sized buffer from the ringbuffer and writes it to a specified destination
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* \param dst Destination pointer
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* \param offset Offset in milliseconds against current position, may be negative
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*/
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void read( sampleFrame * dst, float offset );
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/** \brief Reads a buffer of specified size from the ringbuffer and writes it to a specified destination
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* \param dst Destination pointer
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* \param offset Offset in frames against current position, may be negative
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* \param length Length in frames of the buffer to read - must not be higher than the size of the ringbuffer!
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*/
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void read( sampleFrame * dst, f_cnt_t offset, f_cnt_t length );
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/** \brief Reads a buffer of specified size from the ringbuffer and writes it to a specified destination
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* \param dst Destination pointer
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* \param offset Offset in milliseconds against current position, may be negative
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* \param length Length in frames of the buffer to read - must not be higher than the size of the ringbuffer!
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*/
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void read( sampleFrame * dst, float offset, f_cnt_t length );
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// write functions
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/** \brief Writes a buffer of sampleframes to the ringbuffer at specified position
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* \param src Pointer to the source buffer
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* \param offset Offset in frames against current position, may *NOT* be negative
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* \param length Length of the source buffer, if zero, period size is used - must not be higher than the size of the ringbuffer!
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*/
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void write( sampleFrame * src, f_cnt_t offset=0, f_cnt_t length=0 );
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/** \brief Writes a buffer of sampleframes to the ringbuffer at specified position
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* \param src Pointer to the source buffer
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* \param offset Offset in milliseconds against current position, may *NOT* be negative
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* \param length Length of the source buffer, if zero, period size is used - must not be higher than the size of the ringbuffer!
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*/
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void write( sampleFrame * src, float offset, f_cnt_t length=0 );
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/** \brief Mixes a buffer of sampleframes additively to the ringbuffer at specified position
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* \param src Pointer to the source buffer
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* \param offset Offset in frames against current position, may *NOT* be negative
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* \param length Length of the source buffer, if zero, period size is used - must not be higher than the size of the ringbuffer!
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*/
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void writeAdding( sampleFrame * src, f_cnt_t offset=0, f_cnt_t length=0 );
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/** \brief Mixes a buffer of sampleframes additively to the ringbuffer at specified position
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* \param src Pointer to the source buffer
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* \param offset Offset in milliseconds against current position, may *NOT* be negative
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* \param length Length of the source buffer, if zero, period size is used - must not be higher than the size of the ringbuffer!
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*/
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void writeAdding( sampleFrame * src, float offset, f_cnt_t length=0 );
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/** \brief Mixes a buffer of sampleframes additively to the ringbuffer at specified position, with
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* a specified multiplier applied to the frames
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* \param src Pointer to the source buffer
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* \param offset Offset in frames against current position, may *NOT* be negative
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* \param length Length of the source buffer, if zero, period size is used - must not be higher than the size of the ringbuffer!
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* \param level Multiplier applied to the frames before they're written to the ringbuffer
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*/
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void writeAddingMultiplied( sampleFrame * src, f_cnt_t offset, f_cnt_t length, float level );
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/** \brief Mixes a buffer of sampleframes additively to the ringbuffer at specified position, with
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* a specified multiplier applied to the frames
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* \param src Pointer to the source buffer
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* \param offset Offset in milliseconds against current position, may *NOT* be negative
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* \param length Length of the source buffer, if zero, period size is used
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* \param level Multiplier applied to the frames before they're written to the ringbuffer
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*/
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void writeAddingMultiplied( sampleFrame * src, float offset, f_cnt_t length, float level );
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protected slots:
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void updateSamplerate();
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private:
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inline f_cnt_t msToFrames( float ms )
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{
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return static_cast<f_cnt_t>( ceilf( ms * m_samplerate / 1000 ) );
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}
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const fpp_t m_fpp;
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sample_rate_t m_samplerate;
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f_cnt_t m_size;
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sampleFrame * m_buffer;
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QMutex m_ringBufferMutex;
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f_cnt_t m_position;
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};
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#endif
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