127 lines
3.8 KiB
C++
127 lines
3.8 KiB
C++
/*
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* VstEventQueue.h
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* ---------------
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* Purpose: Event queue for VST events.
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* Notes : Modelled after an idea from https://www.kvraudio.com/forum/viewtopic.php?p=3043807#p3043807
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* Authors: OpenMPT Devs
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* The OpenMPT source code is released under the BSD license. Read LICENSE for more details.
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*/
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#pragma once
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#include "openmpt/all/BuildSettings.hpp"
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#include <deque>
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#include "mpt/mutex/mutex.hpp"
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#include "VstDefinitions.h"
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OPENMPT_NAMESPACE_BEGIN
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class VstEventQueue : public Vst::VstEvents
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{
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protected:
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// Although originally all event types were apparently supposed to be of the same size, this is not the case on 64-Bit systems.
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// VstMidiSysexEvent contains 3 pointers, so the struct size differs between 32-Bit and 64-Bit systems.
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union Event
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{
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Vst::VstEvent event;
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Vst::VstMidiEvent midi;
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Vst::VstMidiSysexEvent sysex;
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};
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// Here we store our events which are then inserted into the fixed-size event buffer sent to the plugin.
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std::deque<Event> eventQueue;
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// Since plugins can also add events to the queue (even from a different thread than the processing thread),
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// we need to ensure that reading and writing is never done in parallel.
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mpt::mutex criticalSection;
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public:
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VstEventQueue()
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{
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numEvents = 0;
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reserved = 0;
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std::fill(std::begin(events), std::end(events), nullptr);
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}
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// Get the number of events that are currently queued, but not in the output buffer.
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size_t GetNumQueuedEvents()
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{
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return eventQueue.size() - numEvents;
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}
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// Add a VST event to the queue. Returns true on success.
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// Set insertFront to true to prioritise this event (i.e. add it at the front of the queue instead of the back)
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bool Enqueue(const Vst::VstEvent *event, bool insertFront = false)
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{
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MPT_ASSERT(event->type != Vst::kVstSysExType || event->byteSize == sizeof(Vst::VstMidiSysexEvent));
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MPT_ASSERT(event->type != Vst::kVstMidiType || event->byteSize == sizeof(Vst::VstMidiEvent));
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Event copyEvent;
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size_t copySize;
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// randomid by Insert Piz Here sends events of type kVstMidiType, but with a claimed size of 24 bytes instead of 32.
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// Hence, we enforce the size of known events.
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if(event->type == Vst::kVstSysExType)
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copySize = sizeof(Vst::VstMidiSysexEvent);
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else if(event->type == Vst::kVstMidiType)
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copySize = sizeof(Vst::VstMidiEvent);
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else
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copySize = std::min(size_t(event->byteSize), sizeof(copyEvent));
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memcpy(©Event, event, copySize);
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if(event->type == Vst::kVstSysExType)
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{
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// SysEx messages need to be copied, as the space used for the dump might be freed in the meantime.
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auto &e = copyEvent.sysex;
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auto sysexDump = new (std::nothrow) std::byte[e.dumpBytes];
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if(sysexDump == nullptr)
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return false;
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memcpy(sysexDump, e.sysexDump, e.dumpBytes);
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e.sysexDump = sysexDump;
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}
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mpt::lock_guard<mpt::mutex> lock(criticalSection);
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if(insertFront)
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eventQueue.push_front(copyEvent);
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else
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eventQueue.push_back(copyEvent);
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return true;
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}
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// Set up the queue for transmitting to the plugin. Returns number of elements that are going to be transmitted.
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int32 Finalise()
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{
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mpt::lock_guard<mpt::mutex> lock(criticalSection);
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numEvents = static_cast<int32>(std::min(eventQueue.size(), MAX_EVENTS));
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for(int32 i = 0; i < numEvents; i++)
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{
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events[i] = &eventQueue[i].event;
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}
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return numEvents;
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}
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// Remove transmitted events from the queue
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void Clear()
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{
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mpt::lock_guard<mpt::mutex> lock(criticalSection);
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if(numEvents)
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{
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// Release temporarily allocated buffer for SysEx messages
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for(auto e = eventQueue.begin(); e != eventQueue.begin() + numEvents; ++e)
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{
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if(e->event.type == Vst::kVstSysExType)
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{
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delete[] e->sysex.sysexDump;
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}
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}
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eventQueue.erase(eventQueue.begin(), eventQueue.begin() + numEvents);
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numEvents = 0;
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}
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}
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};
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OPENMPT_NAMESPACE_END
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