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# SPDX-FileCopyrightText: 2016 Ole Martin Bjorndalen <ombdalen@gmail.com>
#
# SPDX-License-Identifier: MIT
"""Definitions and lookup tables for MIDI messages.
TODO:
* add lookup functions for messages definitions by type and status
byte.
"""
# TODO: these include undefined messages.
CHANNEL_MESSAGES = set(range(0x80, 0xf0))
COMMON_MESSAGES = set(range(0xf0, 0xf8))
REALTIME_MESSAGES = set(range(0xf8, 0x100))
SYSEX_START = 0xf0
SYSEX_END = 0xf7
# Pitchwheel is a 14 bit signed integer
MIN_PITCHWHEEL = -8192
MAX_PITCHWHEEL = 8191
# Song pos is a 14 bit unsigned integer
MIN_SONGPOS = 0
MAX_SONGPOS = 16383
def _defmsg(status_byte, type_, value_names, length):
return {
'status_byte': status_byte,
'type': type_,
'value_names': value_names,
'attribute_names': set(value_names) | {'type', 'time'},
'length': length,
}
SPECS = [
_defmsg(0x80, 'note_off', ('channel', 'note', 'velocity'), 3),
_defmsg(0x90, 'note_on', ('channel', 'note', 'velocity'), 3),
_defmsg(0xa0, 'polytouch', ('channel', 'note', 'value'), 3),
_defmsg(0xb0, 'control_change', ('channel', 'control', 'value'), 3),
_defmsg(0xc0, 'program_change', ('channel', 'program',), 2),
_defmsg(0xd0, 'aftertouch', ('channel', 'value',), 2),
_defmsg(0xe0, 'pitchwheel', ('channel', 'pitch',), 3),
# System common messages.
# 0xf4 and 0xf5 are undefined.
_defmsg(0xf0, 'sysex', ('data',), float('inf')),
_defmsg(0xf1, 'quarter_frame', ('frame_type', 'frame_value'), 2),
_defmsg(0xf2, 'songpos', ('pos',), 3),
_defmsg(0xf3, 'song_select', ('song',), 2),
_defmsg(0xf6, 'tune_request', (), 1),
# System real time messages.
# 0xf9 and 0xfd are undefined.
_defmsg(0xf8, 'clock', (), 1),
_defmsg(0xfa, 'start', (), 1),
_defmsg(0xfb, 'continue', (), 1),
_defmsg(0xfc, 'stop', (), 1),
_defmsg(0xfe, 'active_sensing', (), 1),
_defmsg(0xff, 'reset', (), 1),
]
def _make_spec_lookups(specs):
lookup = {}
by_status = {}
by_type = {}
for spec in specs:
type_ = spec['type']
status_byte = spec['status_byte']
by_type[type_] = spec
if status_byte in CHANNEL_MESSAGES:
for channel in range(16):
by_status[status_byte | channel] = spec
else:
by_status[status_byte] = spec
lookup.update(by_status)
lookup.update(by_type)
return lookup, by_status, by_type
SPEC_LOOKUP, SPEC_BY_STATUS, SPEC_BY_TYPE = _make_spec_lookups(SPECS)
REALTIME_TYPES = {'tune_request', 'clock', 'start', 'continue', 'stop'}
DEFAULT_VALUES = {
'channel': 0,
'control': 0,
'data': (),
'frame_type': 0,
'frame_value': 0,
'note': 0,
'pitch': 0,
'pos': 0,
'program': 0,
'song': 0,
'value': 0,
'velocity': 64,
'time': 0,
}
# TODO: should this be in decode.py?
def make_msgdict(type_, overrides):
"""Return a new message.
Returns a dictionary representing a message.
Message values can be overriden.
No type or value checking is done. The caller is responsible for
calling check_msgdict().
"""
if type_ in SPEC_BY_TYPE:
spec = SPEC_BY_TYPE[type_]
else:
raise LookupError(f'Unknown message type {type_!r}')
msg = {'type': type_, 'time': DEFAULT_VALUES['time']}
for name in spec['value_names']:
msg[name] = DEFAULT_VALUES[name]
msg.update(overrides)
return msg
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