old as heck

ssf4-fixsvs.py

# Usage: fixsvs.py [path] (optional)

import os, sys
import struct
from binascii import crc32

if len(sys.argv) > 1:
    dir = sys.argv[1]
else:
    dir = "."

system = os.path.join(dir, "system.sav")
system = open(system, "rb+")
svs = system.read()

entries = []
num_entries = len(svs) / 0x10

# Tag <-> entry index ordering is important (hardcoded)
# [0] = #SVS (system.sav)
# [1] = #PRG (progress.sav)
# [2] = #FIG (figure.sav)
# [3] = #JST (injustic.sav)
for entry in range(num_entries):
    entry = struct.unpack_from("<4sIII", svs, entry * 0x10)
    entries.append(list(entry))

print entries

for file in os.listdir(dir):
    path = os.path.join(dir, file)
    if os.path.isdir(path) == True:
        continue

    name, ext = os.path.splitext(file)
    if ext != ".sav": continue
    if name == "system": continue

    file = open(path, "rb")
    buffer = file.read()
    file.close()

    size = len(buffer)

    # Game uses bog standard CRC32 without the final bitwise NOT.
    # crc32() will do this NOT so we must undo it.
    crc = (~(crc32(buffer) & 0xFFFFFFFF)) & 0xFFFFFFFF

    tag = struct.unpack_from("4s", buffer)[0];
    tags = [entry[0] for entry in entries]

    print (tag, name, hex(crc))

    if tag not in tags:
        raise ValueError("Tag %s does not exist in SVS." % tag)

    index = tags.index(tag)
    if index == 0: raise ValueError("Tried to update SVS.")

    # Update SVS entry for this file.
    entry = entries[index]

    entry[2] = size
    entry[3] = crc

    entries[index] = entry

# With all files done, we need to recalculate the SVS CRC over itself.
# This is done by first setting the CRC field to the contents of the tag field ("#SVS").
svs_entry = entries[0]
svs_entry[3] = struct.unpack("<I", svs_entry[0])[0]
entries[0] = svs_entry

svs = ""
for entry in range(num_entries):
    svs += struct.pack("<4sIII", *entries[entry])

crc = (~(crc32(svs) & 0xFFFFFFFF)) & 0xFFFFFFFF
svs_entry[3] = crc
entries[0] = svs_entry

print entries

svs = ""
for entry in range(num_entries):
    svs += struct.pack("<4sIII", *entries[entry])

# Write the fixed SVS table.
system.seek(0)
system.write(svs)
system.close()