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livetrax/libs/evoral/evoral/EventRingBuffer.hpp
David Robillard fc77ae0738 Replace a bunch of potential crashes with graceful handling of the situation.
We really need some kind of more sophisticated assert macro that can be
switched to non-fatal logging mode for release builds.  A log message, which is
often all that would happen, is a lot better than a trainwrecked performance...


git-svn-id: svn://localhost/ardour2/branches/3.0@13892 d708f5d6-7413-0410-9779-e7cbd77b26cf
2013-01-19 07:00:43 +00:00

135 lines
3.8 KiB
C++

/* This file is part of Evoral.
* Copyright (C) 2008 David Robillard <http://drobilla.net>
*
* Evoral 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.
*
* Evoral 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 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.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef EVORAL_EVENT_RING_BUFFER_HPP
#define EVORAL_EVENT_RING_BUFFER_HPP
#include <iostream>
#include "pbd/ringbufferNPT.h"
#include "evoral/EventSink.hpp"
#include "evoral/types.hpp"
using namespace std;
namespace Evoral {
/** A RingBuffer of events (generic time-stamped binary "blobs").
*
* This packs a timestamp, size, and size bytes of data flat into the buffer.
* Useful for MIDI events, OSC messages, etc.
*
* Note: the uint8_t template argument to RingBufferNPT<> indicates "byte
* oriented data", not anything particular linked to MIDI or any other
* possible interpretation of uint8_t.
*/
template<typename Time>
class EventRingBuffer : public PBD::RingBufferNPT<uint8_t>, public Evoral::EventSink<Time> {
public:
/** @param capacity Ringbuffer capacity in bytes.
*/
EventRingBuffer(size_t capacity) : PBD::RingBufferNPT<uint8_t>(capacity)
{}
inline size_t capacity() const { return bufsize(); }
/** Peek at the ringbuffer (read w/o advancing read pointer).
* @return how much has been peeked (wraps around if read exceeds
* the end of the buffer):
* <pre>
* |===========--------------R=============================|
* read-pointer---^
* </pre>
*/
inline bool peek (uint8_t*, size_t size);
inline uint32_t write(Time time, EventType type, uint32_t size, const uint8_t* buf);
inline bool read (Time* time, EventType* type, uint32_t* size, uint8_t* buf);
};
template<typename Time>
inline bool
EventRingBuffer<Time>::peek (uint8_t* buf, size_t size)
{
PBD::RingBufferNPT<uint8_t>::rw_vector vec;
get_read_vector (&vec);
if (vec.len[0] + vec.len[1] < size) {
return false;
}
if (vec.len[0] > 0) {
memcpy (buf, vec.buf[0], min (vec.len[0], size));
}
if (vec.len[0] < size) {
if (vec.len[1]) {
memcpy (buf + vec.len[0], vec.buf[1], size - vec.len[0]);
}
}
return true;
}
template<typename Time>
inline bool
EventRingBuffer<Time>::read(Time* time, EventType* type, uint32_t* size, uint8_t* buf)
{
if (PBD::RingBufferNPT<uint8_t>::read ((uint8_t*)time, sizeof (Time)) != sizeof (Time)) {
return false;
}
if (PBD::RingBufferNPT<uint8_t>::read ((uint8_t*)type, sizeof(EventType)) != sizeof (EventType)) {
return false;
}
if (PBD::RingBufferNPT<uint8_t>::read ((uint8_t*)size, sizeof(uint32_t)) != sizeof (uint32_t)) {
return false;
}
if (PBD::RingBufferNPT<uint8_t>::read (buf, *size) != *size) {
return false;
}
return true;
}
template<typename Time>
inline uint32_t
EventRingBuffer<Time>::write(Time time, EventType type, uint32_t size, const uint8_t* buf)
{
if (!buf || write_space() < (sizeof(Time) + sizeof(EventType) + sizeof(uint32_t) + size)) {
return 0;
} else {
PBD::RingBufferNPT<uint8_t>::write ((uint8_t*)&time, sizeof(Time));
PBD::RingBufferNPT<uint8_t>::write ((uint8_t*)&type, sizeof(EventType));
PBD::RingBufferNPT<uint8_t>::write ((uint8_t*)&size, sizeof(uint32_t));
PBD::RingBufferNPT<uint8_t>::write (buf, size);
return size;
}
}
} // namespace Evoral
#endif // EVORAL_EVENT_RING_BUFFER_HPP