Created
August 25, 2018 20:15
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Utility to strip metadata from NSF2 files.
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#!/usr/bin/env python3 | |
import sys | |
assert sys.version_info[0] >= 3, "Python 3 required." | |
# | |
# nsf2_strip.py | |
# Brad Smith, 2018-08-25 | |
# | |
# This strips metadata from NSF2 files. | |
# | |
import struct | |
in_nsf2 = "in.nsf" | |
out_nsf = "out.nsf" | |
show_cut = True | |
def nsf2_strip(nsf2): | |
if len(nsf2) < 0x80: | |
raise Exception("NSF2 too short for header?") | |
nsf = bytearray(nsf2) | |
version = nsf[5] | |
nsf2_bits = nsf[0x7E] | |
if version >= 2 and (nsf2_bits & 0x80) != 0: | |
raise Exception("NSF2 metadata is flagged as essential.") | |
suffix = nsf[0x7D] | (nsf[0x7E]<<8) | (nsf[0x7F]<<16) | |
nsf[0x7D] = 0 | |
nsf[0x7E] = 0 | |
nsf[0x7F] = 0 | |
stripped = 0 | |
if suffix != 0: | |
cut = suffix + 0x80 | |
if cut > len(nsf): | |
raise Exception("NSF2 metadata pointer is past end of file?") | |
stripped = len(nsf) - cut | |
nsf = nsf[0:cut] | |
if show_cut: | |
print("%d bytes stripped." % stripped) | |
return nsf | |
print("Reading " + in_nsf2 + "...") | |
nsf2 = open(in_nsf2,"rb").read() | |
nsf = nsf2_strip(nsf2) | |
print("Saving " + out_nsf + "...") | |
open(out_nsf,"wb").write(nsf) | |
print ("Done.") |
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