/*
    Copyright (C) 2006-2007 Paul Davis 
	Author: Dave Robillard
    
    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.,
    675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include <iostream>
#include <ardour/midi_buffer.h>

#ifdef __x86_64__
static const int CPU_CACHE_ALIGN = 64;
#else
static const int CPU_CACHE_ALIGN = 16; /* arguably 32 on most arches, but it matters less */
#endif

using namespace std;

namespace ARDOUR {


// FIXME: mirroring for MIDI buffers?
MidiBuffer::MidiBuffer(size_t capacity)
	: Buffer(DataType::MIDI, capacity)
//	, _owns_data(true)
	, _events(NULL)
	, _data(NULL)
{
	assert(capacity > 0);

	_size = 0;

#ifdef NO_POSIX_MEMALIGN
	_events = (MidiEvent *) malloc(sizeof(MidiEvent) * capacity);
	_data = (Byte *) malloc(sizeof(Byte) * capacity * MAX_EVENT_SIZE);
#else
	posix_memalign((void**)&_events, CPU_CACHE_ALIGN, sizeof(MidiEvent) * capacity);
	posix_memalign((void**)&_data, CPU_CACHE_ALIGN, sizeof(Byte) * capacity * MAX_EVENT_SIZE);
#endif	
	assert(_data);
	assert(_events);
	silence(_capacity);
}

void
MidiBuffer::copy(const MidiBuffer& copy)
{
	assert(_capacity >= copy._capacity);
	_size = 0;

	for (size_t i=0; i < copy.size(); ++i)
		push_back(copy[i]);
}

MidiBuffer::~MidiBuffer()
{
	free(_events);
	free(_data);
}


/** Read events from @a src starting at time @a offset into the START of this buffer, for
 * time direction @a nframes.  Relative time, where 0 = start of buffer.
 *
 * Note that offset and nframes refer to sample time, NOT buffer offsets or event counts.
 */
void
MidiBuffer::read_from(const Buffer& src, nframes_t nframes, nframes_t offset)
{
	assert(src.type() == DataType::MIDI);
	const MidiBuffer& msrc = (MidiBuffer&)src;

	assert(_capacity >= src.size());

	clear();
	assert(_size == 0);

	// FIXME: slow
	for (size_t i=0; i < src.size(); ++i) {
		const MidiEvent& ev = msrc[i];
		if (ev.time() >= offset && ev.time() < offset+nframes) {
			//cerr << "MidiBuffer::read_from got event, " << ev.time() << endl;
			push_back(ev);
		} else {
			//cerr << "MidiBuffer event out of range, " << ev.time() << endl;
		}
	}

	_silent = src.silent();
}


/** Push an event into the buffer.
 *
 * Note that the raw MIDI pointed to by ev will be COPIED and unmodified.
 * That is, the caller still owns it, if it needs freeing it's Not My Problem(TM).
 * Realtime safe.
 * @return false if operation failed (not enough room)
 */
bool
MidiBuffer::push_back(const MidiEvent& ev)
{
	if (_size == _capacity)
		return false;

	Byte* const write_loc = _data + (_size * MAX_EVENT_SIZE);

	memcpy(write_loc, ev.buffer(), ev.size());
	_events[_size] = ev;
	_events[_size].set_buffer(write_loc);
	++_size;

	//cerr << "MidiBuffer: pushed, size = " << _size << endl;

	_silent = false;

	return true;
}


/** Push an event into the buffer.
 *
 * Note that the raw MIDI pointed to by ev will be COPIED and unmodified.
 * That is, the caller still owns it, if it needs freeing it's Not My Problem(TM).
 * Realtime safe.
 * @return false if operation failed (not enough room)
 */
bool
MidiBuffer::push_back(const jack_midi_event_t& ev)
{
	if (_size == _capacity)
		return false;

	Byte* const write_loc = _data + (_size * MAX_EVENT_SIZE);

	memcpy(write_loc, ev.buffer, ev.size);
	_events[_size].time() = (double)ev.time;
	_events[_size].size() = ev.size;
	_events[_size].set_buffer(write_loc);
	++_size;

	//cerr << "MidiBuffer: pushed, size = " << _size << endl;

	_silent = false;

	return true;
}


/** Reserve space for a new event in the buffer.
 *
 * This call is for copying MIDI directly into the buffer, the data location
 * (of sufficient size to write \a size bytes) is returned, or NULL on failure.
 * This call MUST be immediately followed by a write to the returned data
 * location, or the buffer will be corrupted and very nasty things will happen.
 */
Byte*
MidiBuffer::reserve(double time, size_t size)
{
	assert(size <= MAX_EVENT_SIZE);

	if (_size == _capacity)
		return NULL;

	Byte* const write_loc = _data + (_size * MAX_EVENT_SIZE);

	_events[_size].time() = time;
	_events[_size].size() = size;
	_events[_size].set_buffer(write_loc);
	++_size;

	//cerr << "MidiBuffer: reserved, size = " << _size << endl;

	_silent = false;

	return write_loc;
}


void
MidiBuffer::silence(nframes_t dur, nframes_t offset)
{
	// FIXME use parameters
	assert(offset == 0);
	//assert(dur == _capacity);

	memset(_events, 0, sizeof(MidiEvent) * _capacity);
	memset(_data, 0, sizeof(Byte) * _capacity * MAX_EVENT_SIZE);
	_size = 0;
	_silent = true;
}


/** Clear, and merge \a a and \a b into this buffer.
 *
 * FIXME: This is slow.
 *
 * \return true if complete merge was successful
 */
bool
MidiBuffer::merge(const MidiBuffer& a, const MidiBuffer& b)
{
	_size = 0;

	// Die if a merge isn't necessary as it's expensive
	assert(a.size() > 0 && b.size() > 0);

	size_t a_index = 0;
	size_t b_index = 0;
	size_t count = a.size() + b.size();

	while (count > 0 && a_index < a.size() && b_index < b.size()) {
		
		if (size() == capacity()) {
			cerr << "WARNING: MIDI buffer overrun, events lost!" << endl;
			return false;
		}
		
		if (a_index == a.size()) {
			push_back(a[a_index]);
			++a_index;
		} else if (b_index == b.size()) {
			push_back(b[b_index]);
			++b_index;
		} else {
			const MidiEvent& a_ev = a[a_index];
			const MidiEvent& b_ev = b[b_index];

			if (a_ev.time() <= b_ev.time()) {
				push_back(a_ev);
				++a_index;
			} else {
				push_back(b_ev);
				++b_index;
			}
		}

		--count;
	}

	return true;
}


} // namespace ARDOUR