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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/***************************************************************************
* cachemanager.h
*
* Fri Apr 10 10:39:24 CEST 2015
* Copyright 2015 Jonas Suhr Christensen
* jsc@umbraculum.org
****************************************************************************/
/*
* This file is part of DrumGizmo.
*
* DrumGizmo 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.
*
* DrumGizmo 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 DrumGizmo; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*/
#ifndef __DRUMGIZMO_CACHEMANAGER_H__
#define __DRUMGIZMO_CACHEMANAGER_H__
#include <string>
#include <list>
#include <vector>
#include "thread.h"
#include "semaphore.h"
#include "mutex.h"
#include "audiotypes.h"
#include "audiofile.h"
#define CACHE_DUMMYID -2
#define CACHE_NOID -1
#define FRAMESIZE 256
#define CHUNKSIZE FRAMESIZE*100
class AudioFile;
typedef int cacheid_t;
//TODO:
// 1: Move nodata initialisation to init method.
// 2: Make semaphore in thread to block init call until thread has been started.
//// next
// Pre: preloaded contains 2 x framesize. chunk size is framesize.
// allocate 2 chunks and copy initial_samples_needed to first buffer from
// preloaded data and enough to fill up the second buffer from preloaded
// returns the first buffer and its size in &size.
// get id from "free stack" and store pointers to buffers in id vector.
// event: open sndfile handle (if not already open) and increase refcount
//// next
// Return which ever buffer is the front, swap them and add event to load the
// next chunk.
//// close
// decrement file handle refcounter and close file if it is 0.
// free the 2 buffers
// (do not erase from the id vector), push index to
// "free stack" for reuse.
class CacheManager : public Thread {
public:
/**
* Empty constructor...
*/
CacheManager();
/**
* Destroy object and stop thread if needed.
*/
~CacheManager();
/**
* Initialise cache manager and allocate needed resources
* This method starts the cache manager thread.
* This method blocks until the thread has been started.
* @param poolsize The maximum number of parellel events supported.
*/
void init(size_t poolsize);
/**
* Stop thread and clean up resources.
* This method blocks until the thread has stopped.
*/
void deinit();
/**
* Register new cache entry.
* Prepares an entry in the cache manager for future disk streaming.
* @param file A pointer to the file which is to be streamed from.
* @param initial_samples_needed The number of samples needed in the first
* read that is not nessecarily of framesize. This is the number of samples
* from the input event offset to the end of the frame in which it resides.
* initial_samples_needed <= framesize.
* @param channel The channel to which the cache id will be bound.
* @param [out] new_id The newly created cache id.
* @return A pointer to the first buffer containing the
* 'initial_samples_needed' number of samples.
*/
sample_t *open(AudioFile *file, size_t initial_samples_needed, int channel,
cacheid_t &new_id);
/**
* Get next buffer.
* Returns the next buffer for reading based on cache id.
* This function will (if needed) schedule a new disk read to make sure that
* data is available in the next call to this method.
* @param id The cache id to read from.
* @param [out] size The size of the returned buffer.
* @return A pointer to the buffer.
*/
sample_t *next(cacheid_t id, size_t &size);
/**
* Unregister cache entry.
* Close associated file handles and free associated buffers.
* @param id The cache id to close.
*/
void close(cacheid_t id);
///! Internal thread main method - needs to be public.
void thread_main();
private:
typedef struct {
AudioFile *file;
size_t channel;
size_t pos; //< File possition
sample_t *front;
sample_t *back;
size_t localpos; //< Intra buffer (front) position.
} cache_t;
typedef enum {
LOADNEXT = 0,
CLOSE = 1
} cmd_t;
typedef struct {
cmd_t cmd;
// For close event:
cacheid_t id;
// For load next event:
size_t pos;
sample_t *buffer;
AudioFile *file;
size_t channel;
} cevent_t;
cevent_t createLoadNextEvent(AudioFile *file, size_t channel, size_t pos,
sample_t* buffer);
cevent_t createCloseEvent(cacheid_t id);
void handleLoadNextEvent(cevent_t &e);
void handleCloseEvent(cevent_t &e);
void pushEvent(cevent_t e);
std::vector<cache_t> id2cache;
// Protected by mutex:
std::list<cevent_t> eventqueue;
std::list<cacheid_t> availableids;
Mutex m_events;
Mutex m_ids;
Semaphore sem;
bool running;
};
#endif/*__DRUMGIZMO_CACHEMANAGER_H__*/
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