gs2c.py

#!/usr/bin/env python

from __future__ import print_function

import sys
import os.path

def parseint(s):
    if s.startswith('$'):
        return int(s[1:], 16)
    return int(s)

def hexint(n):
    return '$' + hex(n)[2:].upper()

def convert(filename):
    lines = []
    with open(filename, 'r') as f:
        for line in f:
            line = line.strip()
            line = convert_line(line)
            if not(line.startswith(';') or line.endswith(':') or not line):
                line = '\t\t' + line
            lines.append(line)
    return '\n'.join(lines)

def convert_line(line):
    # Example: db oct0 == octave 1
    # Example: db oct5 == octave 6
    if line.startswith('db oct'):
        octave = parseint(line[6:]) + 1
        return 'octave %s' % (octave,)

    # Example: db (ntA# | 0) == note A#, 1
    # Example: db (ntRst | 3) == note __, 4
    if line.startswith('db (nt'):
        _, note, _, length = line.split(None, 3)
        note = note.lstrip('(')[2:]
        length = length.rstrip(')')
        if note == 'Rst':
            note = '__'
        elif not note.endswith('#'):
            note += '_'
        length = parseint(length) + 1
        return 'note %s, %s' % (note, length)

    # Example: pkmsSetVel 1, 3 == intensity $13
    if line.startswith('pkmsSetVel'):
        _, vel, length = line.split(None, 2)
        vel = parseint(vel.rstrip(','))
        length = parseint(length)
        intensity = hexint((vel << 4) | length)
        return 'intensity %s' % (intensity,)

    # Example: pkmsSetNtr $C, 9, 4 == notetype $C, $94
    if line.startswith('pkmsSetNtr'):
        _, speed, vel, length = line.split(None, 3)
        speed = parseint(speed.rstrip(','))
        vel = parseint(vel.rstrip(','))
        length = parseint(length)
        intensity = hexint((vel << 4) | length)
        return 'notetype %s, %s' % (speed, intensity)

    # Example: pkmsSetDSpeed $C == notetype $C
    if line.startswith('pkmsSetDSpeed'):
        _, speed = line.split(None, 1)
        return 'notetype %s' % (speed,)

    # Example: pkmsEndSound == endchannel
    if line.startswith('pkmsEndSound'):
        return 'endchannel'

    # Example: pkmsSetMod $C, 1, 2 == vibrato $C, $12
    if line.startswith('pkmsSetMod'):
        _, delay, depth, rate = line.split(None, 3)
        delay = delay.rstrip(',')
        depth = parseint(depth.rstrip(','))
        rate = parseint(rate)
        extent = hexint((depth << 4) | rate)
        return 'notetype %s, %s' % (delay, extent)

    # Example: pkmsSetDuty 2 == dutycycle 2
    if line.startswith('pkmsSetDuty'):
        _, duty = line.split(None, 1)
        return 'dutycycle %s' % (duty,)

    # Example: pkmsSetDrums 5 == togglenoise 5
    if line.startswith('pkmsSetDrums'):
        _, drums = line.split(None, 1)
        return 'togglenoise %s' % (drums,)

    # Example: pkmsSetArp $C == unknownmusic0xde $C
    if line.startswith('pkmsSetArp'):
        _, x = line.split(None, 1)
        return 'unknownmusic0xde %s' % (x,)

    # Example: pkmsSetTempo 0, $80 == tempo $80
    if line.startswith('pkmsSetTempo'):
        _, divider, modifier = line.split(None, 2)
        divider = divider.rstrip(',')
        hi = parseint(divider)
        lo = parseint(modifier)
        tempo = hexint((hi << 8) | lo)
        return 'tempo %s' % (tempo,)

    # Example: pkmsSetVolume $77 == volume $77
    if line.startswith('pkmsSetVolume'):
        _, volume = line.split(None, 1)
        return 'volume %s' % (volume,)

    # Example: pkmsCall NewSong_Channel1 + SONG_START == callchannel NewSong_Channel1
    if line.startswith('pkmsCall'):
        _, offset = line.split(None, 1)
        offset = offset.replace('+ SONG_START', '')
        return 'callchannel %s' % (offset,)

    # Example: pkmsJump Channel1_Loop + SONG_START == loopchannel 0, Channel1_Loop
    if line.startswith('pkmsJump'):
        _, offset = line.split(None, 1)
        offset = offset.replace('+ SONG_START', '')
        return 'loopchannel 0, %s' % (offset,)

    if line.startswith(';') or line.endswith(':') or not line:
        return line

    return line + ' ; WARNING: unconverted'

def write(content, old_filename):
    name, ext = os.path.splitext(old_filename)
    new_filename = name + '_c' + '.' + ext
    with open(new_filename, 'w') as f:
        f.write(content)

def main():
    if len(sys.argv) < 2:
        print('Usage: gs2c.py filename.asm', file=sys.stderr)
        sys.exit(1)
    filename = sys.argv[1]
    content = convert(filename)
    write(content, filename)

if __name__ == '__main__':
    main()