Extract Compressed Data from Monster Hunter G (Wii) fpk files

extract_fpk.py

from struct import unpack
from os import makedirs
from os.path import exists

sortme = [] #I don't trust that this is sorted
with open("0000.fpk", "rb") as f:
    #read header, make sure it's valid
    unknown, entry_count, header_size, total_size = unpack(">4I", f.read(0x10))
    f.seek(0, 2)
    assert total_size == f.tell()
    f.seek(0x10)
    assert header_size == 0x10

    #read each entry for processing in a moment
    for i in range(entry_count):
        filepath, offset, cmpsize, decsize = unpack(">36s3I", f.read(0x30))
        filepath = filepath.rstrip(b"\0")
        if len(filepath) == 31:
            print("%s possibly truncated" % filepath)
        sortme.append((filepath, offset, cmpsize, decsize))

    sortme.sort(key=lambda x: x[1]) #sort by offset
    for entry in sortme:
        (filepath, offset, cmpsize, decsize) = entry
        f.seek(offset)
        #put everything in output/
        path = b"output/" + b"/".join(filepath.split(b"/")[:-1])
        if not exists(path): #create path if it doesn't exist
            makedirs(path)
        with open(b"output/%s" % filepath, "wb") as o:
            o.write(f.read(cmpsize))
        print(b"%s done" % filepath)

Thank you so much for this. It was extremely useful.