Mercurial > hg > svcore
view base/Scavenger.h @ 335:02d2ad95ea52 spectrogram-cache-rejig
* Get storage advice for each cache in an FFT data server. Allows us to be
more confident about the actual memory situation and cut over from memory
to disc part way through an FFT calculation if necessary. StorageAdviser
is now a bit too optimistic though (it's too keen to allocate large numbers
of small blocks in memory).
author | Chris Cannam |
---|---|
date | Tue, 13 Nov 2007 13:54:10 +0000 |
parents | 218605f94073 |
children | b14064bd1f97 |
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/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */ /* Sonic Visualiser An audio file viewer and annotation editor. Centre for Digital Music, Queen Mary, University of London. This file copyright 2006 Chris Cannam. 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. See the file COPYING included with this distribution for more information. */ /* This is a modified version of a source file from the Rosegarden MIDI and audio sequencer and notation editor. This file copyright 2000-2006 Chris Cannam. */ #ifndef _SCAVENGER_H_ #define _SCAVENGER_H_ #include "system/System.h" #include <vector> #include <list> #include <sys/time.h> #include <QMutex> #include <iostream> /** * A very simple class that facilitates running things like plugins * without locking, by collecting unwanted objects and deleting them * after a delay so as to be sure nobody's in the middle of using * them. Requires scavenge() to be called regularly from a non-RT * thread. * * This is currently not at all suitable for large numbers of objects * -- it's just a quick hack for use with things like plugins. */ template <typename T> class Scavenger { public: Scavenger(int sec = 2, int defaultObjectListSize = 200); ~Scavenger(); /** * Call from an RT thread etc., to pass ownership of t to us. * Only one thread should be calling this on any given scavenger. */ void claim(T *t); /** * Call from a non-RT thread. * Only one thread should be calling this on any given scavenger. */ void scavenge(bool clearNow = false); protected: typedef std::pair<T *, int> ObjectTimePair; typedef std::vector<ObjectTimePair> ObjectTimeList; ObjectTimeList m_objects; int m_sec; typedef std::list<T *> ObjectList; ObjectList m_excess; int m_lastExcess; QMutex m_excessMutex; void pushExcess(T *); void clearExcess(int); unsigned int m_claimed; unsigned int m_scavenged; }; /** * A wrapper to permit arrays to be scavenged. */ template <typename T> class ScavengerArrayWrapper { public: ScavengerArrayWrapper(T *array) : m_array(array) { } ~ScavengerArrayWrapper() { delete[] m_array; } private: T *m_array; }; template <typename T> Scavenger<T>::Scavenger(int sec, int defaultObjectListSize) : m_objects(ObjectTimeList(defaultObjectListSize)), m_sec(sec), m_lastExcess(0), m_claimed(0), m_scavenged(0) { } template <typename T> Scavenger<T>::~Scavenger() { if (m_scavenged < m_claimed) { for (size_t i = 0; i < m_objects.size(); ++i) { ObjectTimePair &pair = m_objects[i]; if (pair.first != 0) { T *ot = pair.first; pair.first = 0; delete ot; ++m_scavenged; } } } clearExcess(0); } template <typename T> void Scavenger<T>::claim(T *t) { // std::cerr << "Scavenger::claim(" << t << ")" << std::endl; struct timeval tv; (void)gettimeofday(&tv, 0); int sec = tv.tv_sec; for (size_t i = 0; i < m_objects.size(); ++i) { ObjectTimePair &pair = m_objects[i]; if (pair.first == 0) { pair.second = sec; pair.first = t; ++m_claimed; return; } } std::cerr << "WARNING: Scavenger::claim(" << t << "): run out of slots, " << "using non-RT-safe method" << std::endl; pushExcess(t); } template <typename T> void Scavenger<T>::scavenge(bool clearNow) { // std::cerr << "Scavenger::scavenge: scavenged " << m_scavenged << ", claimed " << m_claimed << std::endl; if (m_scavenged >= m_claimed) return; struct timeval tv; (void)gettimeofday(&tv, 0); int sec = tv.tv_sec; for (size_t i = 0; i < m_objects.size(); ++i) { ObjectTimePair &pair = m_objects[i]; if (clearNow || (pair.first != 0 && pair.second + m_sec < sec)) { T *ot = pair.first; pair.first = 0; delete ot; ++m_scavenged; } } if (sec > m_lastExcess + m_sec) { clearExcess(sec); } } template <typename T> void Scavenger<T>::pushExcess(T *t) { m_excessMutex.lock(); m_excess.push_back(t); struct timeval tv; (void)gettimeofday(&tv, 0); m_lastExcess = tv.tv_sec; m_excessMutex.unlock(); } template <typename T> void Scavenger<T>::clearExcess(int sec) { m_excessMutex.lock(); for (typename ObjectList::iterator i = m_excess.begin(); i != m_excess.end(); ++i) { delete *i; } m_excess.clear(); m_lastExcess = sec; m_excessMutex.unlock(); } #endif