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livetrax/libs/ardour/midi_ring_buffer.cc

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/*
Copyright (C) 2006-2008 Paul Davis
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 "pbd/compose.h"
#include "pbd/error.h"
#include "ardour/debug.h"
#include "ardour/midi_ring_buffer.h"
#include "ardour/midi_buffer.h"
#include "ardour/event_type_map.h"
using namespace std;
using namespace ARDOUR;
using namespace PBD;
/** Read a block of MIDI events from this buffer into a MidiBuffer.
*
* Timestamps of events returned are relative to start (i.e. event with stamp 0
* occurred at start), with offset added.
*/
template<typename T>
size_t
MidiRingBuffer<T>::read(MidiBuffer& dst, framepos_t start, framepos_t end, framecnt_t offset, bool stop_on_overflow_in_dst)
{
if (this->read_space() == 0) {
return 0;
}
T ev_time;
Evoral::EventType ev_type;
uint32_t ev_size;
/* If we see the end of a loop during this read, we must write the events after it
to the MidiBuffer with adjusted times. The situation is as follows:
session frames----------------------------->
| | |
start_of_loop start end_of_loop
The MidiDiskstream::read method which will have happened before this checks for
loops ending, and helpfully inserts a magic LoopEvent into the ringbuffer. After this,
the MidiDiskstream continues to write events with their proper session frame times,
so after the LoopEvent event times will go backwards (ie non-monotonically).
Once we hit end_of_loop, we need to fake it to make it look as though the loop has been
immediately repeated. Say that an event E after the end_of_loop in the ringbuffer
has time E_t, which is a time in session frames. Its offset from the start
of the loop will be E_t - start_of_loop. Its `faked' time will therefore be
end_of_loop + E_t - start_of_loop. And so its port-buffer-relative time (for
writing to the MidiBuffer) will be end_of_loop + E_t - start_of_loop - start.
The subtraction of start is already taken care of, so if we see a LoopEvent, we'll
set up loop_offset to equal end_of_loop - start_of_loop, so that given an event
time E_t in the ringbuffer we can get the port-buffer-relative time as
E_t + offset - start.
*/
frameoffset_t loop_offset = 0;
size_t count = 0;
const size_t prefix_size = sizeof(T) + sizeof(Evoral::EventType) + sizeof(uint32_t);
while (this->read_space() >= prefix_size) {
uint8_t peekbuf[prefix_size];
bool success;
success = this->peek (peekbuf, prefix_size);
/* this cannot fail, because we've already verified that there
is prefix_space to read
*/
assert (success);
ev_time = *((T*) peekbuf);
ev_type = *((Evoral::EventType*)(peekbuf + sizeof (T)));
ev_size = *((uint32_t*)(peekbuf + sizeof(T) + sizeof (Evoral::EventType)));
if (ev_time + loop_offset >= end) {
DEBUG_TRACE (DEBUG::MidiDiskstreamIO, string_compose ("MRB event @ %1 past end @ %2\n", ev_time, end));
break;
} else if (ev_time + loop_offset < start) {
DEBUG_TRACE (DEBUG::MidiDiskstreamIO, string_compose ("MRB event @ %1 before start @ %2\n", ev_time, start));
break;
} else {
DEBUG_TRACE (DEBUG::MidiDiskstreamIO, string_compose ("MRB event @ %1 in range %2 .. %3\n", ev_time, start, end));
}
assert(ev_time >= start);
ev_time -= start;
ev_time += offset;
// This event marks a loop end (i.e. the next event's timestamp
// will be non-monotonic). Don't write it into the buffer - the
// significance of this event ends here.
if (ev_type == LoopEventType) {
assert (ev_size == sizeof (framepos_t));
framepos_t loop_start;
read_contents (ev_size, (uint8_t *) &loop_start);
loop_offset = ev_time - loop_start;
_tracker.resolve_notes (dst, ev_time);
continue;
}
/* we're good to go ahead and read the data now but since we
* have the prefix data already, just skip over that
*/
this->increment_read_ptr (prefix_size);
ev_time += loop_offset;
uint8_t status;
success = this->peek (&status, sizeof(uint8_t));
assert(success); // If this failed, buffer is corrupt, all hope is lost
// Ignore event if it doesn't match channel filter
if (is_channel_event(status) && get_channel_mode() == FilterChannels) {
const uint8_t channel = status & 0x0F;
if (!(get_channel_mask() & (1L << channel))) {
DEBUG_TRACE (DEBUG::MidiDiskstreamIO, string_compose ("MRB skipping event (%3 bytes) due to channel mask (mask = %1 chn = %2)\n",
get_channel_mask(), (int) channel, ev_size));
this->increment_read_ptr (ev_size); // Advance read pointer to next event
continue;
}
}
/* lets see if we are going to be able to write this event into dst.
*/
uint8_t* write_loc = dst.reserve (ev_time, ev_size);
if (write_loc == 0) {
if (stop_on_overflow_in_dst) {
DEBUG_TRACE (DEBUG::MidiDiskstreamIO, string_compose ("MidiRingBuffer: overflow in destination MIDI buffer, stopped after %1 events\n", count));
break;
}
error << "MRB: Unable to reserve space in buffer, event skipped" << endmsg;
this->increment_read_ptr (ev_size); // Advance read pointer to next event
continue;
}
// write MIDI buffer contents
success = read_contents (ev_size, write_loc);
#ifndef NDEBUG
if (DEBUG::MidiDiskstreamIO && PBD::debug_bits) {
DEBUG_STR_DECL(a);
DEBUG_STR_APPEND(a, string_compose ("wrote MidiEvent to Buffer (time=%1, start=%2 offset=%3)", ev_time, start, offset));
for (size_t i=0; i < ev_size; ++i) {
DEBUG_STR_APPEND(a,hex);
DEBUG_STR_APPEND(a,"0x");
DEBUG_STR_APPEND(a,(int)write_loc[i]);
DEBUG_STR_APPEND(a,' ');
}
DEBUG_STR_APPEND(a,'\n');
DEBUG_TRACE (DEBUG::MidiDiskstreamIO, DEBUG_STR(a).str());
}
#endif
if (success) {
if (is_note_on(write_loc[0]) ) {
_tracker.add (write_loc[1], write_loc[0] & 0xf);
} else if (is_note_off(write_loc[0])) {
_tracker.remove (write_loc[1], write_loc[0] & 0xf);
}
if (is_channel_event(status) && get_channel_mode() == ForceChannel) {
write_loc[0] = (write_loc[0] & 0xF0) | (get_channel_mask() & 0x0F);
}
++count;
} else {
cerr << "WARNING: error reading event contents from MIDI ring" << endl;
}
}
return count;
}
template<typename T>
void
MidiRingBuffer<T>::dump(ostream& str)
{
size_t rspace;
if ((rspace = this->read_space()) == 0) {
str << "MRB::dump: empty\n";
return;
}
T ev_time;
Evoral::EventType ev_type;
uint32_t ev_size;
RingBufferNPT<uint8_t>::rw_vector vec;
RingBufferNPT<uint8_t>::get_read_vector (&vec);
if (vec.len[0] == 0) {
return;
}
str << this << ": Dump size = " << vec.len[0] + vec.len[1]
<< " r@ " << RingBufferNPT<uint8_t>::get_read_ptr()
<< " w@" << RingBufferNPT<uint8_t>::get_write_ptr() << endl;
uint8_t *buf = new uint8_t[vec.len[0] + vec.len[1]];
memcpy (buf, vec.buf[0], vec.len[0]);
if (vec.len[1]) {
memcpy (buf+vec.len[1], vec.buf[1], vec.len[1]);
}
uint8_t* data = buf;
const uint8_t* end = buf + vec.len[0] + vec.len[1];
while (data < end) {
memcpy (&ev_time, data, sizeof (T));
data += sizeof (T);
str << "\ttime " << ev_time;
if (data >= end) {
str << "(incomplete)\n ";
break;
}
memcpy (&ev_type, data, sizeof (ev_type));
data += sizeof (ev_type);
str << " type " << ev_type;
if (data >= end) {
str << "(incomplete)\n";
break;
}
memcpy (&ev_size, data, sizeof (ev_size));
data += sizeof (ev_size);
str << " size " << ev_size;
if (data >= end) {
str << "(incomplete)\n";
break;
}
for (uint32_t i = 0; i != ev_size && data < end; ++i) {
str << ' ' << hex << (int) data[i] << dec;
}
data += ev_size;
str << endl;
}
delete [] buf;
}
template<typename T>
void
MidiRingBuffer<T>::reset_tracker ()
{
_tracker.reset ();
}
template class MidiRingBuffer<framepos_t>;
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