engines/gig/InstrumentResourceManager.cpp

/***************************************************************************
 *                                                                         *
 *   LinuxSampler - modular, streaming capable sampler                     *
 *                                                                         *
 *   Copyright (C) 2003, 2004 by Benno Senoner and Christian Schoenebeck   *
 *   Copyright (C) 2005 - 2012 Christian Schoenebeck                       *
 *                                                                         *
 *   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., 59 Temple Place, Suite 330, Boston,                 *
 *   MA  02111-1307  USA                                                   *
 ***************************************************************************/

#include <sstream>

#include "InstrumentResourceManager.h"
#include "EngineChannel.h"
#include "Engine.h"

#include "../../common/global_private.h"
#include "../../plugins/InstrumentEditorFactory.h"

namespace LinuxSampler { namespace gig {

    // some data needed for the libgig callback function
    struct progress_callback_arg_t {
        InstrumentResourceManager*          pManager;
        InstrumentManager::instrument_id_t* pInstrumentKey;
    };

    // we use this to react on events concerning an instrument on behalf of an instrument editor
    class InstrumentEditorProxy : public InstrumentConsumer {
    public:
        virtual void ResourceToBeUpdated(::gig::Instrument* pResource, void*& pUpdateArg) {
            //TODO: inform the instrument editor about the pending update
        }

        virtual void ResourceUpdated(::gig::Instrument* pOldResource, ::gig::Instrument* pNewResource, void* pUpdateArg) {
            //TODO:: inform the instrument editor about finished update
        }

        virtual void OnResourceProgress(float fProgress) {
            //TODO: inform the instrument editor about the progress of an update
        }

        // the instrument we borrowed on behalf of the editor
        ::gig::Instrument* pInstrument;
        // the instrument editor we work on behalf
        InstrumentEditor* pEditor;
    };

    /**
     * Callback function which will be called by libgig during loading of
     * instruments to inform about the current progress. Or to be more
     * specific; it will be called during the GetInstrument() call.
     *
     * @param pProgress - contains current progress value, pointer to the
     *                    InstrumentResourceManager instance and
     *                    instrument ID
     */
    void InstrumentResourceManager::OnInstrumentLoadingProgress(::gig::progress_t* pProgress) {
        dmsg(7,("gig::InstrumentResourceManager: progress %f%", pProgress->factor));
        progress_callback_arg_t* pArg = static_cast<progress_callback_arg_t*>(pProgress->custom);
        // we randomly schedule 90% for the .gig file loading and the remaining 10% later for sample caching
        const float localProgress = 0.9f * pProgress->factor;
        pArg->pManager->DispatchResourceProgressEvent(*pArg->pInstrumentKey, localProgress);
    }

    String InstrumentResourceManager::GetInstrumentName(instrument_id_t ID) {
        Lock();
        ::gig::Instrument* pInstrument = Resource(ID, false);
        String res = (pInstrument) ? pInstrument->pInfo->Name : "";
        Unlock();
        return res;
    }

    String InstrumentResourceManager::GetInstrumentDataStructureName(instrument_id_t ID) {
        return ::gig::libraryName();
    }

    String InstrumentResourceManager::GetInstrumentDataStructureVersion(instrument_id_t ID) {
        return ::gig::libraryVersion();
    }

    std::vector<InstrumentResourceManager::instrument_id_t> InstrumentResourceManager::GetInstrumentFileContent(String File) throw (InstrumentManagerException) {
        ::RIFF::File* riff = NULL;
        ::gig::File*  gig  = NULL;
        try {
            std::vector<instrument_id_t> result;
            riff = new ::RIFF::File(File);
            gig  = new ::gig::File(riff);
            gig->SetAutoLoad(false); // avoid time consuming samples scanning
            for (int i = 0; gig->GetInstrument(i); i++) {
                instrument_id_t id;
                id.FileName = File;
                id.Index    = i;
                result.push_back(id);
            }
            if (gig)  delete gig;
            if (riff) delete riff;
            return result;
        } catch (::RIFF::Exception e) {
            if (gig)  delete gig;
            if (riff) delete riff;
            throw InstrumentManagerException(e.Message);
        } catch (...) {
            if (gig)  delete gig;
            if (riff) delete riff;
            throw InstrumentManagerException("Unknown exception while trying to parse '" + File + "'");
        }
    }

    InstrumentResourceManager::instrument_info_t InstrumentResourceManager::GetInstrumentInfo(instrument_id_t ID) throw (InstrumentManagerException) {
        Lock();
        ::gig::Instrument* pInstrument = Resource(ID, false);
        bool loaded = (pInstrument != NULL);
        if (!loaded) Unlock();

        ::RIFF::File* riff = NULL;
        ::gig::File*  gig  = NULL;
        try {
            if (!loaded) {
                riff = new ::RIFF::File(ID.FileName);
                gig  = new ::gig::File(riff);
                gig->SetAutoLoad(false); // avoid time consuming samples scanning
                pInstrument = gig->GetInstrument(ID.Index);
            }

            if (!pInstrument) throw InstrumentManagerException("There is no instrument " + ToString(ID.Index) + " in " + ID.FileName);

            instrument_info_t info;
            for (int i = 0; i < 128; i++) { info.KeyBindings[i] = info.KeySwitchBindings[i] = 0; }

            ::gig::File* pFile = (::gig::File*) pInstrument->GetParent();

            if (pFile->pVersion) {
                info.FormatVersion = ToString(pFile->pVersion->major);
                info.Product = pFile->pInfo->Product;
                info.Artists = pFile->pInfo->Artists;
            }

            info.InstrumentName = pInstrument->pInfo->Name;

            ::gig::Region* pRegion = pInstrument->GetFirstRegion();
            while (pRegion) {
                int low = pRegion->KeyRange.low;
                int high = pRegion->KeyRange.high;
                if (low < 0 || low > 127 || high < 0 || high > 127 || low > high) {
                    std::cerr << "Invalid key range: " << low << " - " << high << std::endl;
                } else {
                    for (int i = low; i <= high; i++) info.KeyBindings[i] = 1;
                }

                pRegion = pInstrument->GetNextRegion();
            }

            if (loaded) { // retrieve keyswitching only if the instrument is fully loaded.

                // only return keyswitch range if keyswitching is used
                bool hasKeyswitches = false;
                for (::gig::Region* pRegion = pInstrument->GetFirstRegion() ;
                     pRegion && !hasKeyswitches ;
                     pRegion = pInstrument->GetNextRegion()) {
                    for (int i = 0 ; i < pRegion->Dimensions ; i++) {
                        if (pRegion->pDimensionDefinitions[i].dimension == ::gig::dimension_keyboard) {
                            hasKeyswitches = true;
                            break;
                        }
                    }
                }

                if (hasKeyswitches) {
                    int low = pInstrument->DimensionKeyRange.low;
                    int high = pInstrument->DimensionKeyRange.high;
                    if (low < 0 || low > 127 || high < 0 || high > 127 || low > high) {
                        std::cerr << "Invalid keyswitch range: " << low << " - " << high << std::endl;
                    } else {
                        for (int i = low; i <= high; i++) info.KeySwitchBindings[i] = 1;
                    }
                }
            }

            if (loaded) Unlock();

            if (gig)  delete gig;
            if (riff) delete riff;
            return info;
        } catch (::RIFF::Exception e) {
            if (loaded) Unlock();
            if (gig)  delete gig;
            if (riff) delete riff;
            throw InstrumentManagerException(e.Message);
        } catch (...) {
            if (loaded) Unlock();
            if (gig)  delete gig;
            if (riff) delete riff;
            throw InstrumentManagerException("Unknown exception while trying to parse '" + ID.FileName + "'");
        }
    }

    InstrumentEditor* InstrumentResourceManager::LaunchInstrumentEditor(instrument_id_t ID, void* pUserData) throw (InstrumentManagerException) {
        const String sDataType    = GetInstrumentDataStructureName(ID);
        const String sDataVersion = GetInstrumentDataStructureVersion(ID);
        // find instrument editors capable to handle given instrument
        std::vector<String> vEditors =
            InstrumentEditorFactory::MatchingEditors(sDataType, sDataVersion);
        if (!vEditors.size())
            throw InstrumentManagerException(
                "There is no instrument editor capable to handle this instrument"
            );
        // simply use the first editor in the result set
        dmsg(1,("Found matching editor '%s' for instrument ('%s', %d) having data structure ('%s','%s')\n",
            vEditors[0].c_str(), ID.FileName.c_str(), ID.Index, sDataType.c_str(), sDataVersion.c_str()));
        InstrumentEditor* pEditor = InstrumentEditorFactory::Create(vEditors[0]);
        // register for receiving notifications from the instrument editor
        pEditor->AddListener(this);
        // create a proxy that reacts on notification on behalf of the editor
        InstrumentEditorProxy* pProxy = new InstrumentEditorProxy;
        // borrow the instrument on behalf of the instrument editor
        ::gig::Instrument* pInstrument = Borrow(ID, pProxy);
        // remember the proxy and instrument for this instrument editor
        pProxy->pInstrument = pInstrument;
        pProxy->pEditor     = pEditor;
        InstrumentEditorProxiesMutex.Lock();
        InstrumentEditorProxies.add(pProxy);
        InstrumentEditorProxiesMutex.Unlock();
        // launch the instrument editor for the given instrument
        pEditor->Launch(pInstrument, sDataType, sDataVersion, pUserData);

        // register the instrument editor as virtual MIDI device as well ...
        VirtualMidiDevice* pVirtualMidiDevice =
            dynamic_cast<VirtualMidiDevice*>(pEditor);
        if (!pVirtualMidiDevice) {
            std::cerr << "Instrument editor not a virtual MIDI device\n" << std::flush;
            return pEditor;
        }
        // NOTE: for now connect the virtual MIDI keyboard of the instrument editor (if any) with all engine channels that have the same instrument as the editor was opened for ( other ideas ? )
        Lock();
        std::set<EngineChannel*> engineChannels =
            GetEngineChannelsUsing(pInstrument, false/*don't lock again*/);
        std::set<EngineChannel*>::iterator iter = engineChannels.begin();
        std::set<EngineChannel*>::iterator end  = engineChannels.end();
        for (; iter != end; ++iter) (static_cast<AbstractEngineChannel*>(*iter))->Connect(pVirtualMidiDevice);
        Unlock();

        return pEditor;
    }

    /**
     * Will be called by the respective instrument editor once it left its
     * Main() loop. That way we can handle cleanup before its thread finally
     * dies.
     *
     * @param pSender - instrument editor that stops execution
     */
    void InstrumentResourceManager::OnInstrumentEditorQuit(InstrumentEditor* pSender) {
        dmsg(1,("InstrumentResourceManager: instrument editor quit, doing cleanup\n"));

        ::gig::Instrument* pInstrument = NULL;
        InstrumentEditorProxy* pProxy  = NULL;
        int iProxyIndex                = -1;

        // first find the editor proxy entry for this editor
        InstrumentEditorProxiesMutex.Lock();
        for (int i = 0; i < InstrumentEditorProxies.size(); i++) {
            InstrumentEditorProxy* pCurProxy =
                dynamic_cast<InstrumentEditorProxy*>(
                    InstrumentEditorProxies[i]
                );
            if (pCurProxy->pEditor == pSender) {
                pProxy      = pCurProxy;
                iProxyIndex = i;
                pInstrument = pCurProxy->pInstrument;
            }
        }
        InstrumentEditorProxiesMutex.Unlock();

        if (!pProxy) {
            std::cerr << "Eeeek, could not find instrument editor proxy, "
                         "this is a bug!\n" << std::flush;
            return;
        }

        // now unregister editor as not being available as a virtual MIDI device anymore
        VirtualMidiDevice* pVirtualMidiDevice =
            dynamic_cast<VirtualMidiDevice*>(pSender);
        if (pVirtualMidiDevice) {
            Lock();
            // NOTE: see note in LaunchInstrumentEditor()
            std::set<EngineChannel*> engineChannels =
                GetEngineChannelsUsing(pInstrument, false/*don't lock again*/);
            std::set<EngineChannel*>::iterator iter = engineChannels.begin();
            std::set<EngineChannel*>::iterator end  = engineChannels.end();
            for (; iter != end; ++iter) (*iter)->Disconnect(pVirtualMidiDevice);
            Unlock();
        } else {
            std::cerr << "Could not unregister editor as not longer acting as "
                         "virtual MIDI device. Wasn't it registered?\n"
                      << std::flush;
        }

        // finally delete proxy entry and hand back instrument
        if (pInstrument) {
            InstrumentEditorProxiesMutex.Lock();
            InstrumentEditorProxies.remove(iProxyIndex);
            InstrumentEditorProxiesMutex.Unlock();

            HandBack(pInstrument, pProxy);
            delete pProxy;
        }

        // Note that we don't need to free the editor here. As it
        // derives from Thread, it will delete itself when the thread
        // dies.
    }

#if 0 // currently unused :
    /**
     * Try to inform the respective instrument editor(s), that a note on
     * event just occured. This method is called by the MIDI thread. If any
     * obstacles are in the way (e.g. if a wait for an unlock would be
     * required) we give up immediately, since the RT safeness of the MIDI
     * thread has absolute priority.
     */
    void InstrumentResourceManager::TrySendNoteOnToEditors(uint8_t Key, uint8_t Velocity, ::gig::Instrument* pInstrument) {
        const bool bGotLock = InstrumentEditorProxiesMutex.Trylock(); // naively assumes RT safe implementation
        if (!bGotLock) return; // hell, forget it, not worth the hassle
        for (int i = 0; i < InstrumentEditorProxies.size(); i++) {
            InstrumentEditorProxy* pProxy =
                dynamic_cast<InstrumentEditorProxy*>(
                    InstrumentEditorProxies[i]
                );
            if (pProxy->pInstrument == pInstrument)
                pProxy->pEditor->SendNoteOnToDevice(Key, Velocity);
        }
        InstrumentEditorProxiesMutex.Unlock(); // naively assumes RT safe implementation
    }

    /**
     * Try to inform the respective instrument editor(s), that a note off
     * event just occured. This method is called by the MIDI thread. If any
     * obstacles are in the way (e.g. if a wait for an unlock would be
     * required) we give up immediately, since the RT safeness of the MIDI
     * thread has absolute priority.
     */
    void InstrumentResourceManager::TrySendNoteOffToEditors(uint8_t Key, uint8_t Velocity, ::gig::Instrument* pInstrument) {
        const bool bGotLock = InstrumentEditorProxiesMutex.Trylock(); // naively assumes RT safe implementation
        if (!bGotLock) return; // hell, forget it, not worth the hassle
        for (int i = 0; i < InstrumentEditorProxies.size(); i++) {
            InstrumentEditorProxy* pProxy =
                dynamic_cast<InstrumentEditorProxy*>(
                    InstrumentEditorProxies[i]
                );
            if (pProxy->pInstrument == pInstrument)
                pProxy->pEditor->SendNoteOffToDevice(Key, Velocity);
        }
        InstrumentEditorProxiesMutex.Unlock(); // naively assumes RT safe implementation
    }
#endif // unused

    void InstrumentResourceManager::OnSamplesToBeRemoved(std::set<void*> Samples, InstrumentEditor* pSender) {
        if (Samples.empty()) {
            std::cerr << "gig::InstrumentResourceManager: WARNING, "
                         "OnSamplesToBeRemoved() called with empty list, this "
                         "is a bug!\n" << std::flush;
            return;
        }
        // TODO: ATM we assume here that all samples are from the same file
        ::gig::Sample* pFirstSample = (::gig::Sample*) *Samples.begin();
        ::gig::File* pCriticalFile = dynamic_cast< ::gig::File*>(pFirstSample->GetParent());
        // completely suspend all engines that use that same file
        SuspendEnginesUsing(pCriticalFile);
    }

    void InstrumentResourceManager::OnSamplesRemoved(InstrumentEditor* pSender) {
        // resume all previously, completely suspended engines
        // (we don't have to un-cache the removed samples here, since that is
        // automatically done by the gig::Sample destructor)
        ResumeAllEngines();
    }

    void InstrumentResourceManager::OnDataStructureToBeChanged(void* pStruct, String sStructType, InstrumentEditor* pSender) {
        //TODO: remove code duplication
        if (sStructType == "gig::File") {
            // completely suspend all engines that use that file
            ::gig::File* pFile = (::gig::File*) pStruct;
            SuspendEnginesUsing(pFile);
        } else if (sStructType == "gig::Instrument") {
            // completely suspend all engines that use that instrument
            ::gig::Instrument* pInstrument = (::gig::Instrument*) pStruct;
            SuspendEnginesUsing(pInstrument);
        } else if (sStructType == "gig::Region") {
            // only advice the engines to suspend the given region, so they'll
            // only ignore that region (and probably already other suspended
            // ones), but beside that continue normal playback
            ::gig::Region* pRegion = (::gig::Region*) pStruct;
            ::gig::Instrument* pInstrument =
                (::gig::Instrument*) pRegion->GetParent();
            Lock();
            std::set<Engine*> engines =
                GetEnginesUsing(pInstrument, false/*don't lock again*/);
            std::set<Engine*>::iterator iter = engines.begin();
            std::set<Engine*>::iterator end  = engines.end();
            for (; iter != end; ++iter) (*iter)->Suspend(pRegion);
            Unlock();
        } else if (sStructType == "gig::DimensionRegion") {
            // only advice the engines to suspend the given DimensionRegions's
            // parent region, so they'll only ignore that region (and probably
            // already other suspended ones), but beside that continue normal
            // playback
            ::gig::DimensionRegion* pDimReg =
                (::gig::DimensionRegion*) pStruct;
            ::gig::Region* pRegion = pDimReg->GetParent();
            ::gig::Instrument* pInstrument =
                (::gig::Instrument*) pRegion->GetParent();
            Lock();
            std::set<Engine*> engines =
                GetEnginesUsing(pInstrument, false/*don't lock again*/);
            std::set<Engine*>::iterator iter = engines.begin();
            std::set<Engine*>::iterator end  = engines.end();
            for (; iter != end; ++iter) (*iter)->Suspend(pRegion);
            Unlock();
        } else {
            std::cerr << "gig::InstrumentResourceManager: ERROR, unknown data "
                         "structure '" << sStructType << "' requested to be "
                         "suspended by instrument editor. This is a bug!\n"
                      << std::flush;
            //TODO: we should inform the instrument editor that something seriously went wrong
        }
    }

    void InstrumentResourceManager::OnDataStructureChanged(void* pStruct, String sStructType, InstrumentEditor* pSender) {
        //TODO: remove code duplication
        if (sStructType == "gig::File") {
            // resume all previously suspended engines
            ResumeAllEngines();
        } else if (sStructType == "gig::Instrument") {
            // resume all previously suspended engines
            ResumeAllEngines();
        } else if (sStructType == "gig::Sample") {
            // we're assuming here, that OnDataStructureToBeChanged() with
            // "gig::File" was called previously, so we won't resume anything
            // here, but just re-cache the given sample
            Lock();
            ::gig::Sample* pSample = (::gig::Sample*) pStruct;
            ::gig::File* pFile = (::gig::File*) pSample->GetParent();
            UncacheInitialSamples(pSample);
            // now re-cache ...
            std::vector< ::gig::Instrument*> instruments =
                GetInstrumentsCurrentlyUsedOf(pFile, false/*don't lock again*/);
            for (int i = 0; i < instruments.size(); i++) {
                if (SampleReferencedByInstrument(pSample, instruments[i])) {
                    std::set<EngineChannel*> engineChannels =
                        GetEngineChannelsUsing(instruments[i], false/*don't lock again*/);
                    std::set<EngineChannel*>::iterator iter = engineChannels.begin();
                    std::set<EngineChannel*>::iterator end  = engineChannels.end();
                    for (; iter != end; ++iter)
                        CacheInitialSamples(pSample, *iter);
                }
            }
            Unlock();
        } else if (sStructType == "gig::Region") {
            // advice the engines to resume the given region, that is to
            // using it for playback again
            ::gig::Region* pRegion = (::gig::Region*) pStruct;
            ::gig::Instrument* pInstrument =
                (::gig::Instrument*) pRegion->GetParent();
            Lock();
            std::set<Engine*> engines =
                GetEnginesUsing(pInstrument, false/*don't lock again*/);
            std::set<Engine*>::iterator iter = engines.begin();
            std::set<Engine*>::iterator end  = engines.end();
            for (; iter != end; ++iter) (*iter)->Resume(pRegion);
            Unlock();
        } else if (sStructType == "gig::DimensionRegion") {
            // advice the engines to resume the given DimensionRegion's parent
            // region, that is to using it for playback again
            ::gig::DimensionRegion* pDimReg =
                (::gig::DimensionRegion*) pStruct;
            ::gig::Region* pRegion = pDimReg->GetParent();
            ::gig::Instrument* pInstrument =
                (::gig::Instrument*) pRegion->GetParent();
            Lock();
            std::set<Engine*> engines =
                GetEnginesUsing(pInstrument, false/*don't lock again*/);
            std::set<Engine*>::iterator iter = engines.begin();
            std::set<Engine*>::iterator end  = engines.end();
            for (; iter != end; ++iter) (*iter)->Resume(pRegion);
            Unlock();
        } else {
            std::cerr << "gig::InstrumentResourceManager: ERROR, unknown data "
                         "structure '" << sStructType << "' requested to be "
                         "resumed by instrument editor. This is a bug!\n"
                      << std::flush;
            //TODO: we should inform the instrument editor that something seriously went wrong
        }
    }

    void InstrumentResourceManager::OnSampleReferenceChanged(void* pOldSample, void* pNewSample, InstrumentEditor* pSender) {
        // uncache old sample in case it's not used by anybody anymore
        if (pOldSample) {
            Lock();
            ::gig::Sample* pSample = (::gig::Sample*) pOldSample;
            ::gig::File* pFile = (::gig::File*) pSample->GetParent();
            bool bSampleStillInUse = false;
            std::vector< ::gig::Instrument*> instruments =
                GetInstrumentsCurrentlyUsedOf(pFile, false/*don't lock again*/);
            for (int i = 0; i < instruments.size(); i++) {
                if (SampleReferencedByInstrument(pSample, instruments[i])) {
                    bSampleStillInUse = true;
                    break;
                }
            }
            if (!bSampleStillInUse) UncacheInitialSamples(pSample);
            Unlock();
        }
        // make sure new sample reference is cached
        if (pNewSample) {
            Lock();
            ::gig::Sample* pSample = (::gig::Sample*) pNewSample;
            ::gig::File* pFile = (::gig::File*) pSample->GetParent();
            // get all engines that use that same gig::File
            std::set<Engine*> engines = GetEnginesUsing(pFile, false/*don't lock again*/);
            std::set<Engine*>::iterator iter = engines.begin();
            std::set<Engine*>::iterator end  = engines.end();
            for (; iter != end; ++iter)
                CacheInitialSamples(pSample, *iter);
            Unlock();
        }
    }

    ::gig::Instrument* InstrumentResourceManager::Create(instrument_id_t Key, InstrumentConsumer* pConsumer, void*& pArg) {
        // get gig file from internal gig file manager
        ::gig::File* pGig = Gigs.Borrow(Key.FileName, reinterpret_cast<GigConsumer*>(Key.Index)); // conversion kinda hackish :/

        // we pass this to the progress callback mechanism of libgig
        progress_callback_arg_t callbackArg;
        callbackArg.pManager       = this;
        callbackArg.pInstrumentKey = &Key;

        ::gig::progress_t progress;
        progress.callback = OnInstrumentLoadingProgress;
        progress.custom   = &callbackArg;

        dmsg(1,("Loading gig instrument ('%s',%d)...",Key.FileName.c_str(),Key.Index));
        ::gig::Instrument* pInstrument = pGig->GetInstrument(Key.Index, &progress);
        if (!pInstrument) {
            std::stringstream msg;
            msg << "There's no instrument with index " << Key.Index << ".";
            throw InstrumentManagerException(msg.str());
        }
        pGig->GetFirstSample(); // just to force complete instrument loading
        dmsg(1,("OK\n"));

        uint maxSamplesPerCycle = GetMaxSamplesPerCycle(pConsumer);

        // cache initial samples points (for actually needed samples)
        dmsg(1,("Caching initial samples..."));
        uint iRegion = 0; // just for progress calculation
        ::gig::Region* pRgn = pInstrument->GetFirstRegion();
        while (pRgn) {
            // we randomly schedule 90% for the .gig file loading and the remaining 10% now for sample caching
            const float localProgress = 0.9f + 0.1f * (float) iRegion / (float) pInstrument->Regions;
            DispatchResourceProgressEvent(Key, localProgress);

            if (pRgn->GetSample() && !pRgn->GetSample()->GetCache().Size) {
                dmsg(2,("C"));
                CacheInitialSamples(pRgn->GetSample(), maxSamplesPerCycle);
            }
            for (uint i = 0; i < pRgn->DimensionRegions; i++) {
                CacheInitialSamples(pRgn->pDimensionRegions[i]->pSample, maxSamplesPerCycle);
            }

            pRgn = pInstrument->GetNextRegion();
            iRegion++;
        }
        dmsg(1,("OK\n"));
        DispatchResourceProgressEvent(Key, 1.0f); // done; notify all consumers about progress 100%

        // we need the following for destruction later
        instr_entry_t* pEntry = new instr_entry_t;
        pEntry->ID.FileName   = Key.FileName;
        pEntry->ID.Index      = Key.Index;
        pEntry->pFile         = pGig;

        // (try to resolve the audio device context)
        // and we save this to check if we need to reallocate for an engine with higher value of 'MaxSamplesPerSecond'
        pEntry->MaxSamplesPerCycle = maxSamplesPerCycle;
        
        pArg = pEntry;

        return pInstrument;
    }

    void InstrumentResourceManager::Destroy(::gig::Instrument* pResource, void* pArg) {
        instr_entry_t* pEntry = (instr_entry_t*) pArg;
        // we don't need the .gig file here anymore
        Gigs.HandBack(pEntry->pFile, reinterpret_cast<GigConsumer*>(pEntry->ID.Index)); // conversion kinda hackish :/
        delete pEntry;
    }

    void InstrumentResourceManager::DeleteRegionIfNotUsed(::gig::DimensionRegion* pRegion, region_info_t* pRegInfo) {
        // TODO: we could delete Region and Instrument here if they have become unused
    }

    void InstrumentResourceManager::DeleteSampleIfNotUsed(::gig::Sample* pSample, region_info_t* pRegInfo) {
        ::gig::File* gig = pRegInfo->file;
        ::RIFF::File* riff = static_cast< ::RIFF::File*>(pRegInfo->pArg);
        if (gig) {
            gig->DeleteSample(pSample);
            if (!gig->GetFirstSample()) {
                dmsg(2,("No more samples in use - freeing gig\n"));
                delete gig;
                delete riff;
            }
        }
    }

    /**
     * Just a wrapper around the other @c CacheInitialSamples() method.
     *
     *  @param pSample - points to the sample to be cached
     *  @param pEngine - pointer to Gig Engine Channel which caused this call
     *                   (may be NULL, in this case default amount of samples
     *                   will be cached)
     */
    void InstrumentResourceManager::CacheInitialSamples(::gig::Sample* pSample, EngineChannel* pEngineChannel) {
        Engine* pEngine =
            (pEngineChannel && pEngineChannel->GetEngine()) ?
                dynamic_cast<Engine*>(pEngineChannel->GetEngine()) : NULL;
        CacheInitialSamples(pSample, pEngine);
    }

    /**
     *  Caches a certain size at the beginning of the given sample in RAM. If the
     *  sample is very short, the whole sample will be loaded into RAM and thus
     *  no disk streaming is needed for this sample. Caching an initial part of
     *  samples is needed to compensate disk reading latency.
     *
     *  @param pSample - points to the sample to be cached
     *  @param pEngine - pointer to Gig Engine which caused this call
     *                   (may be NULL, in this case default amount of samples
     *                   will be cached)
     */
    void InstrumentResourceManager::CacheInitialSamples(::gig::Sample* pSample, AbstractEngine* pEngine) {
        uint maxSamplesPerCycle =
            (pEngine) ? pEngine->pAudioOutputDevice->MaxSamplesPerCycle() :
            DefaultMaxSamplesPerCycle();
        CacheInitialSamples(pSample, maxSamplesPerCycle);
    }

    void InstrumentResourceManager::CacheInitialSamples(::gig::Sample* pSample, uint maxSamplesPerCycle) {
        if (!pSample) {
            dmsg(4,("gig::InstrumentResourceManager: Skipping sample (pSample == NULL)\n"));
            return;
        }
        if (!pSample->SamplesTotal) return; // skip zero size samples

        if (pSample->SamplesTotal <= CONFIG_PRELOAD_SAMPLES) {
            // Sample is too short for disk streaming, so we load the whole
            // sample into RAM and place 'pAudioIO->FragmentSize << CONFIG_MAX_PITCH'
            // number of '0' samples (silence samples) behind the official buffer
            // border, to allow the interpolator do it's work even at the end of
            // the sample.
            const uint neededSilenceSamples = (maxSamplesPerCycle << CONFIG_MAX_PITCH) + 3;
            const uint currentlyCachedSilenceSamples = pSample->GetCache().NullExtensionSize / pSample->FrameSize;
            if (currentlyCachedSilenceSamples < neededSilenceSamples) {
                dmsg(3,("Caching whole sample (sample name: \"%s\", sample size: %d)\n", pSample->pInfo->Name.c_str(), pSample->SamplesTotal));
                ::gig::buffer_t buf = pSample->LoadSampleDataWithNullSamplesExtension(neededSilenceSamples);
                dmsg(4,("Cached %d Bytes, %d silence bytes.\n", buf.Size, buf.NullExtensionSize));
            }
        }
        else { // we only cache CONFIG_PRELOAD_SAMPLES and stream the other sample points from disk
            if (!pSample->GetCache().Size) pSample->LoadSampleData(CONFIG_PRELOAD_SAMPLES);
        }

        if (!pSample->GetCache().Size) std::cerr << "Unable to cache sample - maybe memory full!" << std::endl << std::flush;
    }

    void InstrumentResourceManager::UncacheInitialSamples(::gig::Sample* pSample) {
        dmsg(1,("Uncaching sample %x\n",pSample));
        if (pSample->GetCache().Size) pSample->ReleaseSampleData();
    }

    /**
     * Returns a list with all instruments currently in use, that are part of
     * the given file.
     *
     * @param pFile - search criteria
     * @param bLock - whether we should lock (mutex) the instrument manager
     *                during this call and unlock at the end of this call
     */
    std::vector< ::gig::Instrument*> InstrumentResourceManager::GetInstrumentsCurrentlyUsedOf(::gig::File* pFile, bool bLock) {
        if (bLock) Lock();
        std::vector< ::gig::Instrument*> result;
        std::vector< ::gig::Instrument*> allInstruments = Resources(false/*don't lock again*/);
        for (int i = 0; i < allInstruments.size(); i++)
            if (
                (::gig::File*) allInstruments[i]->GetParent()
                == pFile
            ) result.push_back(allInstruments[i]);
        if (bLock) Unlock();
        return result;
    }

    /**
     * Returns a list with all gig engine channels that are currently using
     * the given instrument.
     *
     * @param pInstrument - search criteria
     * @param bLock - whether we should lock (mutex) the instrument manager
     *                during this call and unlock at the end of this call
     */
    std::set<EngineChannel*> InstrumentResourceManager::GetEngineChannelsUsing(::gig::Instrument* pInstrument, bool bLock) {
        if (bLock) Lock();
        std::set<EngineChannel*> result;
        std::set<ResourceConsumer< ::gig::Instrument>*> consumers = ConsumersOf(pInstrument);
        std::set<ResourceConsumer< ::gig::Instrument>*>::iterator iter = consumers.begin();
        std::set<ResourceConsumer< ::gig::Instrument>*>::iterator end  = consumers.end();
        for (; iter != end; ++iter) {
            EngineChannel* pEngineChannel = dynamic_cast<EngineChannel*>(*iter);
            if (!pEngineChannel) continue;
            result.insert(pEngineChannel);
        }
        if (bLock) Unlock();
        return result;
    }

    /**
     * Returns a list with all gig Engines that are currently using the given
     * instrument.
     *
     * @param pInstrument - search criteria
     * @param bLock - whether we should lock (mutex) the instrument manager
     *                during this call and unlock at the end of this call
     */
    std::set<Engine*> InstrumentResourceManager::GetEnginesUsing(::gig::Instrument* pInstrument, bool bLock) {
        if (bLock) Lock();
        std::set<Engine*> result;
        std::set<ResourceConsumer< ::gig::Instrument>*> consumers = ConsumersOf(pInstrument);
        std::set<ResourceConsumer< ::gig::Instrument>*>::iterator iter = consumers.begin();
        std::set<ResourceConsumer< ::gig::Instrument>*>::iterator end  = consumers.end();
        for (; iter != end; ++iter) {
            EngineChannel* pEngineChannel = dynamic_cast<EngineChannel*>(*iter);
            if (!pEngineChannel) continue;
            Engine* pEngine = dynamic_cast<Engine*>(pEngineChannel->GetEngine());
            if (!pEngine) continue;
            result.insert(pEngine);
        }
        if (bLock) Unlock();
        return result;
    }

    /**
     * Returns a list with all gig Engines that are currently using an
     * instrument that is part of the given instrument file.
     *
     * @param pFile - search criteria
     * @param bLock - whether we should lock (mutex) the instrument manager
     *                during this call and unlock at the end of this call
     */
    std::set<Engine*> InstrumentResourceManager::GetEnginesUsing(::gig::File* pFile, bool bLock) {
        if (bLock) Lock();
        // get all instruments (currently in usage) that use that same gig::File
        std::vector< ::gig::Instrument*> instrumentsOfInterest =
            GetInstrumentsCurrentlyUsedOf(pFile, false/*don't lock again*/);

        // get all engines that use that same gig::File
        std::set<Engine*> result;
        {
            for (int i = 0; i < instrumentsOfInterest.size(); i++) {
                std::set<ResourceConsumer< ::gig::Instrument>*> consumers = ConsumersOf(instrumentsOfInterest[i]);
                std::set<ResourceConsumer< ::gig::Instrument>*>::iterator iter = consumers.begin();
                std::set<ResourceConsumer< ::gig::Instrument>*>::iterator end  = consumers.end();
                for (; iter != end; ++iter) {
                    EngineChannel* pEngineChannel = dynamic_cast<EngineChannel*>(*iter);
                    if (!pEngineChannel) continue;
                    Engine* pEngine = dynamic_cast<Engine*>(pEngineChannel->GetEngine());
                    if (!pEngine) continue;
                    // the unique, sorted container std::set makes
                    // sure we won't have duplicates
                    result.insert(pEngine);
                }
            }
        }
        if (bLock) Unlock();
        return result;
    }

    /**
     * Returns @c true in case the given sample is referenced somewhere by the
     * given instrument, @c false otherwise.
     *
     * @param pSample - sample reference
     * @param pInstrument - instrument that might use that sample
     */
    bool InstrumentResourceManager::SampleReferencedByInstrument(::gig::Sample* pSample, ::gig::Instrument* pInstrument) {
        for (
            ::gig::Region* pRegion = pInstrument->GetFirstRegion();
            pRegion; pRegion = pInstrument->GetNextRegion()
        ) {
            for (
                int i = 0; i < pRegion->DimensionRegions &&
                pRegion->pDimensionRegions[i]; i++
            ) {
                if (pRegion->pDimensionRegions[i]->pSample == pSample)
                    return true;
            }
        }
        return false;
    }

    /**
     * Suspend all gig engines that use the given instrument. This means
     * completely stopping playback on those engines and killing all their
     * voices and disk streams. This method will block until all voices AND
     * their disk streams are finally deleted and the engine turned into a
     * complete idle loop.
     *
     * All @c SuspendEnginesUsing() methods only serve one thread by one and
     * block all other threads until the current active thread called
     * @c ResumeAllEngines() .
     *
     * @param pInstrument - search criteria
     */
    void InstrumentResourceManager::SuspendEnginesUsing(::gig::Instrument* pInstrument) {
        // make sure no other thread suspends whole engines at the same time
        suspendedEnginesMutex.Lock();
        // get all engines that use that same gig::Instrument
        suspendedEngines = GetEnginesUsing(pInstrument, true/*lock*/);
        // finally, completely suspend all engines that use that same gig::Instrument
        std::set<Engine*>::iterator iter = suspendedEngines.begin();
        std::set<Engine*>::iterator end  = suspendedEngines.end();
        for (; iter != end; ++iter) (*iter)->SuspendAll();
    }

    /**
     * Suspend all gig engines that use the given instrument file. This means
     * completely stopping playback on those engines and killing all their
     * voices and disk streams. This method will block until all voices AND
     * their disk streams are finally deleted and the engine turned into a
     * complete idle loop.
     *
     * All @c SuspendEnginesUsing() methods only serve one thread by one and
     * block all other threads until the current active thread called
     * @c ResumeAllEngines() .
     *
     * @param pFile - search criteria
     */
    void InstrumentResourceManager::SuspendEnginesUsing(::gig::File* pFile) {
        // make sure no other thread suspends whole engines at the same time
        suspendedEnginesMutex.Lock();
        // get all engines that use that same gig::File
        suspendedEngines = GetEnginesUsing(pFile, true/*lock*/);
        // finally, completely suspend all engines that use that same gig::File
        std::set<Engine*>::iterator iter = suspendedEngines.begin();
        std::set<Engine*>::iterator end  = suspendedEngines.end();
        for (; iter != end; ++iter) (*iter)->SuspendAll();
    }

    /**
     * MUST be called after one called one of the @c SuspendEnginesUsing()
     * methods, to resume normal playback on all previously suspended engines.
     * As it's only possible for one thread to suspend whole engines at the
     * same time, this method doesn't take any arguments.
     */
    void InstrumentResourceManager::ResumeAllEngines() {
        // resume all previously completely suspended engines
        std::set<Engine*>::iterator iter = suspendedEngines.begin();
        std::set<Engine*>::iterator end  = suspendedEngines.end();
        for (; iter != end; ++iter) (*iter)->ResumeAll();
        // no more suspended engines ...
        suspendedEngines.clear();
        // allow another thread to suspend whole engines
        suspendedEnginesMutex.Unlock();
    }


    // internal gig file manager

    ::gig::File* InstrumentResourceManager::GigResourceManager::Create(String Key, GigConsumer* pConsumer, void*& pArg) {
        dmsg(1,("Loading gig file \'%s\'...", Key.c_str()));
        ::RIFF::File* pRIFF = new ::RIFF::File(Key);
        ::gig::File* pGig   = new ::gig::File(pRIFF);
        pArg                = pRIFF;
        dmsg(1,("OK\n"));
        return pGig;
    }

    void InstrumentResourceManager::GigResourceManager::Destroy(::gig::File* pResource, void* pArg) {
        dmsg(1,("Freeing gig file '%s' from memory ...", pResource->GetFileName().c_str()));

        // Delete as much as possible of the gig file. Some of the
        // dimension regions and samples may still be in use - these
        // will be deleted later by the HandBackDimReg function.
        bool deleteFile = true;
        ::gig::Instrument* nextInstrument;
        for (::gig::Instrument* instrument = pResource->GetFirstInstrument() ;
             instrument ;
             instrument = nextInstrument) {
            nextInstrument = pResource->GetNextInstrument();
            bool deleteInstrument = true;
            ::gig::Region* nextRegion;
            for (::gig::Region *region = instrument->GetFirstRegion() ;
                 region ;
                 region = nextRegion) {
                nextRegion = instrument->GetNextRegion();
                bool deleteRegion = true;
                for (int i = 0 ; i < region->DimensionRegions ; i++)
                {
                    ::gig::DimensionRegion *d = region->pDimensionRegions[i];
                    std::map< ::gig::DimensionRegion*, region_info_t>::iterator iter = parent->RegionInfo.find(d);
                    if (iter != parent->RegionInfo.end()) {
                        region_info_t& dimRegInfo = (*iter).second;
                        dimRegInfo.file = pResource;
                        dimRegInfo.pArg = (::RIFF::File*)pArg;
                        deleteFile = deleteInstrument = deleteRegion = false;
                    }
                }
                if (deleteRegion) instrument->DeleteRegion(region);
            }
            if (deleteInstrument) pResource->DeleteInstrument(instrument);
        }
        if (deleteFile) {
            delete pResource;
            delete (::RIFF::File*) pArg;
        } else {
            dmsg(2,("keeping some samples that are in use..."));
            ::gig::Sample* nextSample;
            for (::gig::Sample* sample = pResource->GetFirstSample() ;
                 sample ;
                 sample = nextSample) {
                nextSample = pResource->GetNextSample();
                if (parent->SampleRefCount.find(sample) == parent->SampleRefCount.end()) {
                    pResource->DeleteSample(sample);
                }
            }
        }
        dmsg(1,("OK\n"));
    }

}} // namespace LinuxSampler::gig