greaseweazle-firmware/scripts/misc/scp_info.py

import struct, sys

def dump_track(dat, trk_offs, trknr, show_dat):
    print("Track %u:" % trknr)

    trk_off = trk_offs[trknr]
    if trk_off == 0:
        print("Empty")
        return
    
    # Parse the SCP track header and extract the flux data.
    thdr = dat[trk_off:trk_off+4+12*nr_revs]
    sig, tnr, _, _, s_off = struct.unpack("<3sB3I", thdr[:16])
    assert sig == b"TRK"
    assert tnr == trknr
    for i in range(nr_revs):
        t,n,_ = struct.unpack("<3I", thdr[4+i*12:4+(i+1)*12])
        print("Rev %u: time=%uus flux=%u" % (i, t//40, n))
    if not show_dat:
        return
    
    _, e_nr, e_off = struct.unpack("<3I", thdr[-12:])
    tdat = dat[trk_off+s_off:trk_off+e_off+e_nr*2]
    fluxl = []
    while tdat:
        flux, = struct.unpack(">H", tdat[:2])
        tdat = tdat[2:]
        fluxl.append(flux / 40)
    tot = 0.0
    i = 0
    for x in fluxl:
        bad = ""
        if (x < 3.6) or ((x > 4.4) and (x < 5.4)) \
           or ((x > 6.6) and (x < 7.2)) or (x > 8.8):
            bad = "BAD"
        print("%d: %f %s" % (i, x, bad))
        i += 1
        tot += x
    print("Total: %uus (%uus per rev)" % (int(tot), tot//nr_revs))


with open(sys.argv[1], "rb") as f:
    dat = f.read()

header = struct.unpack("<3s9BI", dat[0:16])
(sig, _, _, nr_revs, s_trk, e_trk, flags, _, ss, _, _) = header
assert sig == b"SCP"
nr_sides = 1 if ss else 2
        
trk_offs = struct.unpack("<168I", dat[16:0x2b0])

print("Revolutions: %u" % nr_revs)

if len(sys.argv) == 3:
    dump_track(dat, trk_offs, int(sys.argv[2]), True)
else:
    for i in range(s_trk, e_trk+1):
        dump_track(dat, trk_offs, i, False)