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/* -*- Mode: c++ -*- */
/***************************************************************************
* events_ds.h
*
* Sun Jan 12 00:17:31 CET 2020
* Copyright 2020 André Nusser
* andre.nusser@googlemail.com
****************************************************************************/
/*
* This file is part of DrumGizmo.
*
* DrumGizmo is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 3 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser 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.
*/
#pragma once
#include <config.h>
#include <algorithm>
#include <array>
#include <vector>
#include "events.h"
#include "id.h"
#include "memory_heap.h"
#include "range.h"
#include "instrument.h"
//! EventsDS (events data structure) is the central engine events data structure.
//! It enables the following fast operations:
//! * Add a new event
//! * Remove an event
//! * Iterate over all events of a channel
//! * Get all events of a certain group
//! * ...
//!
//! All operations are constant time (assuming bounded group sizes). Also, it
//! assignes the event ids and group ids. Certain functions may be specific to certain event types.
//!
//! This data structure makes several assumptions about its usage:
//! * we assume that we add a group in one batch without deleting anything in-between
//! * we assume that an event_id isn't used after remove(event_id) was called
//! * we assume that before starting to emplace a new group, startAddingNewGroup is called
// TODO: make it possible to choose sizes of all the containers on initialization
// such that we avoid allocations all together as long as we stay in these bounds.
class EventsDS
{
public:
//! Adds a new event of type T (via emplace syntax) to the data structure.
template <typename T, typename... Args>
T& emplace(channel_t ch, Args&&... args);
//! Removes the event with id being event_id.
void remove(EventID event_id);
//! Returns a reference to the element with id begin event_id. Note that to
//! get an event with this function, one has to know its type!
template <typename T>
T& get(EventID event_id);
//! In case we don't know the type of an event, we can use this function to
//! retrieve it and then use get<Type>(...) to get the event.
Event::Type getType(EventID event_id) const;
//! Returns the number of all events of a certain channel.
std::size_t numberOfEvents(channel_t ch) const;
//! Gives a range that can be used in a range based for loop to iterate over
//! all events in channel ch of type T.
template <typename T>
ContainerRange<std::vector<T>> iterateOver(channel_t ch);
//! Returns all the group ids of sample events associated with instrument_id.
const EventGroupIDs& getSampleEventGroupIDsOf(InstrumentID instrument_id) const;
//! Get all the event ids of events that are in the group with event_group_id.
const EventIDs& getEventIDsOf(EventGroupID event_group_id) const;
//! This function should always be called before we emplace a new batch of
//! events. This internally creates a new group id and then assigns this group
//! id to all the events that are emplaced afterwards. The group id changes,
//! when startAddingNewGroup is again called.
void startAddingNewGroup(InstrumentID instrument_id = InstrumentID());
private:
struct ChannelData
{
std::vector<SampleEvent> sample_events;
};
using ChannelEventIndex = std::size_t;
struct EventInfo
{
Event::Type type;
channel_t ch;
ChannelEventIndex channel_event_index;
EventInfo(Event::Type type, channel_t ch, ChannelEventIndex channel_event_index)
: type(type), ch(ch), channel_event_index(channel_event_index) {}
};
struct GroupData
{
EventIDs event_ids;
// Note: In the future, we could make groups just consist of events of one type.
// Currently that is not necessary, but untested.
// Event::Type type;
// SampleEvent specific data
std::size_t instrument_index;
};
// general data
std::array<ChannelData, NUM_CHANNELS> channel_data_array;
MemoryHeap<EventInfo> id_to_info;
MemoryHeap<GroupData> id_to_group_data;
// SampleEvent specific data
// TODO: Make this into a vector and always have the size be the number of instruments.
std::array<EventGroupIDs, 128> instruments_sample_event_group_ids;
EventGroupID current_group_id;
InstrumentID current_groups_instrument_id;
void removeGroup(EventGroupID group_id, InstrumentID instrument_id = InstrumentID());
template <typename T>
T& getSample(EventInfo const& info);
};
template <typename T, typename... Args>
T& EventsDS::emplace(channel_t ch, Args&&... args)
{
// add new event types here
static_assert(std::is_same<T, SampleEvent>::value);
if (std::is_same<T, SampleEvent>::value)
{
auto& sample_events = channel_data_array[ch].sample_events;
auto channel_event_index = sample_events.size();
sample_events.emplace_back(std::forward<Args>(args)...);
auto event_id = id_to_info.emplace(Event::Type::SampleEvent, ch, channel_event_index);
id_to_group_data.get(current_group_id).event_ids.push_back(event_id);
auto& sample_event = sample_events.back();
sample_event.id = event_id;
sample_event.group_id = current_group_id;
assert(sample_event.instrument_id == current_groups_instrument_id);
assert(sample_event.channel == ch);
return sample_event;
}
}
template <typename T>
T& EventsDS::get(EventID event_id)
{
return getSample<T>(id_to_info.get(event_id));
}
template <typename T>
ContainerRange<std::vector<T>> EventsDS::iterateOver(channel_t ch)
{
// add new event types here
static_assert(std::is_same<T, SampleEvent>::value);
if (std::is_same<T, SampleEvent>::value)
{
auto& sample_events = channel_data_array[ch].sample_events;
return ContainerRange<std::vector<T>>(sample_events.begin(), sample_events.end());
}
}
template <typename T>
T& EventsDS::getSample(EventInfo const& info)
{
// add new event types here
static_assert(std::is_same<T, SampleEvent>::value);
if (std::is_same<T, SampleEvent>::value)
{
return channel_data_array[info.ch].sample_events[info.channel_event_index];
}
}
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