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Code Issues Releases Wiki Activity

port changes from dump to chksum

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This commit is contained in:
Connor Olding 2015-03-01 20:06:21 -08:00
parent 5c33550a0c
commit 2d1cee45bd
1 changed files with 18 additions and 22 deletions
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40
chksum.py
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@ -1,18 +1,14 @@
#!/bin/python
# fixes the checksums in a Majora's Mask US 1.0 savefile for Bizhawk
# fixes the checksums in a Majora's Mask savefile for Bizhawk
# note: copies are ignored and overwritten, so don't bother editing them.
import sys
import struct
import struct, array
lament = lambda *args, **kwargs: print(*args, file=sys.stderr, **kwargs)
chunkize = lambda a, n: (a[i:i+n] for i in range(0, len(a), n))
# seems redundant, but it's a lot less error-prone
pack_u8 = lambda data: struct.pack('>B', data)
pack_u16 = lambda data: struct.pack('>H', data)
unpack_u8 = lambda data: struct.unpack('>B', data)[0]
unpack_u16 = lambda data: struct.unpack('>H', data)[0]
R2 = lambda data: struct.unpack('>H', data)[0]
W2 = lambda data: struct.pack('>H', data)
save_1 = 0x20800
save_2 = 0x24800
@ -25,8 +21,8 @@ owl_2_copy = 0x34800
def calc_sum(data):
chksum = 0
for b in chunkize(data, 1):
chksum += unpack_u8(b)
for b in data:
chksum += b
chksum &= 0xFFFF
return chksum
@ -41,9 +37,9 @@ def fix_sum(f, addr, owl=False):
chksum &= 0xFFFF
f.seek(addr + sum_pos)
old_chksum = unpack_u16(f.read(2))
old_chksum = R2(f.read(2))
f.seek(addr + sum_pos)
f.write(pack_u16(chksum))
f.write(W2(chksum))
lament('{:04X} -> {:04X}'.format(old_chksum, chksum))
def copy_save(f, addr, addr2):
@ -57,12 +53,12 @@ def delete_save(f, addr):
f.seek(addr)
f.write(b'\x00'*0x2000)
def swap_endian(f):
def swap_order(f, size='H'):
f.seek(0)
data = f.read()
a = array.array(size, f.read())
a.byteswap()
f.seek(0)
for s in chunkize(data, 4):
f.write(s[::-1])
f.write(a.tobytes())
def run(args):
args = args[1:]
@ -78,19 +74,19 @@ def run(args):
endian = 'little'
if endian == 'little':
swap_endian(f)
swap_order(f, 'L')
copy_save(f, save_1, save_1_copy)
copy_save(f, save_2, save_2_copy)
copy_save(f, owl_1, owl_1_copy)
copy_save(f, owl_2, owl_2_copy)
fix_sum(f, save_1)
fix_sum(f, save_2)
fix_sum(f, owl_1, owl=True)
fix_sum(f, owl_2, owl=True)
copy_save(f, save_1, save_1_copy)
copy_save(f, save_2, save_2_copy)
copy_save(f, owl_1, owl_1_copy)
copy_save(f, owl_2, owl_2_copy)
if endian == 'little':
swap_endian(f)
swap_order(f, 'L')
return 0
if __name__ == '__main__':