midi_util.h

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/* This file is part of Evoral.
 * Copyright(C) 2008 David Robillard <http://drobilla.net>
 * Copyright(C) 2000-2008 Paul Davis
 *
 * 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_MIDI_UTIL_H
#define EVORAL_MIDI_UTIL_H

#include <iostream>

#include <stdint.h>
#include <string>
#include <sys/types.h>
#include <assert.h>

#include "evoral/visibility.h"
#include "evoral/midi_events.h"

namespace Evoral {


static inline int
midi_event_size(uint8_t status)
{
        // if we have a channel event
        if (status >= 0x80 && status < 0xF0) {
                status &= 0xF0; // mask off the channel
        }

        switch (status) {
        case MIDI_CMD_NOTE_OFF:
        case MIDI_CMD_NOTE_ON:
        case MIDI_CMD_NOTE_PRESSURE:
        case MIDI_CMD_CONTROL:
        case MIDI_CMD_BENDER:
        case MIDI_CMD_COMMON_SONG_POS:
                return 3;

        case MIDI_CMD_PGM_CHANGE:
        case MIDI_CMD_CHANNEL_PRESSURE:
        case MIDI_CMD_COMMON_MTC_QUARTER:
        case MIDI_CMD_COMMON_SONG_SELECT:
                return 2;

        case MIDI_CMD_COMMON_TUNE_REQUEST:
        case MIDI_CMD_COMMON_SYSEX_END:
        case MIDI_CMD_COMMON_CLOCK:
        case MIDI_CMD_COMMON_START:
        case MIDI_CMD_COMMON_CONTINUE:
        case MIDI_CMD_COMMON_STOP:
        case MIDI_CMD_COMMON_SENSING:
        case MIDI_CMD_COMMON_RESET:
                return 1;

        case MIDI_CMD_COMMON_SYSEX:
                std::cerr << "event size called for sysex\n";
                return -1;
        }

        std::cerr << "event size called for unknown status byte " << std::hex << (int) status << "\n";
        return -1;
}

static inline int
midi_event_size(const uint8_t* buffer)
{
        uint8_t status = buffer[0];

        // Mask off channel if applicable
        if (status >= 0x80 && status < 0xF0) {
                status &= 0xF0;
        }

        // see http://www.midi.org/techspecs/midimessages.php
        if (status == MIDI_CMD_COMMON_SYSEX) {
                int end;
                
                for (end = 1; buffer[end] != MIDI_CMD_COMMON_SYSEX_END; end++) {
                        if ((buffer[end] & 0x80) != 0) {
                                return -1;
                        }
                }
                assert(buffer[end] == MIDI_CMD_COMMON_SYSEX_END);
                return end + 1;
        } else {
                return midi_event_size(status);
        }
}

static inline bool
midi_event_is_valid(const uint8_t* buffer, size_t len)
{
        uint8_t status = buffer[0];
        if (status < 0x80) {
                return false;
        }
        const int size = midi_event_size(buffer);
        if (size < 0 || (size_t)size != len) {
                return false;
        }
        if (status < 0xf0) {
                /* Channel messages: all start with status byte followed by
                 * non status bytes.
                 */
                for (size_t i = 1; i < len; ++i) {
                        if ((buffer[i] & 0x80) != 0) {
                                return false;  // Non-status byte has MSb set
                        }
                }
        }
        return true;
}

LIBEVORAL_API std::string midi_note_name (uint8_t noteval);

} // namespace Evoral

#endif // EVORAL_MIDI_UTIL_H