SARCExtract.py

#Only tested on Python 2.7.13 but it *might* work on 3.X
from struct import pack, unpack
from os.path import exists
from os import mkdir, makedirs
import sys
endian = ">" #Initial endian until we read the BOM

def byte(f):
    return unpack("%sB" % endian, f.read(1))[0]
def half(f):
    return unpack("%sH" % endian, f.read(2))[0]
def trip(f):
    return unpack("%sI" % endian, "\x00"+f.read(3))[0]
def full(f):
    return unpack("%sI" % endian, f.read(4))[0]
def getstr(f):
    ret = ""; char = f.read(1)
    while char != "\x00":
        ret += char
        char = f.read(1)
    return ret
    
with open(sys.argv[1], "rb") as f:
    assert f.read(4) == b"SARC"
    assert half(f) == 0x14 #Header size
    endian = ["<", ">"][half(f) & 1]
    f.seek(0, 2)
    size = f.tell()
    f.seek(8, 0)
    assert full(f) == size #Sanity check
    print("size:  %08X" % size)
    align = full(f)
    print("align: %08X" % align)
    f.seek(4, 1) #Probably static
    start1 = f.tell()
    assert f.read(4) == b"SFAT"
    assert half(f) == 0x0C #Header size
    count = half(f)
    start2 = 0x20 + (0x10 * count)
    #NOTE: Data start is not always at [align], so
    #we can read last *name, go there and read it
    #to get the end of SFNT, and then pad that
    f.seek(start2 - 11)
    offset = trip(f)
    f.seek(start2 + 8 + (offset * 4))
    getstr(f)
    start3 = f.tell() + (align - (f.tell() % align))
    #Now we can start extracting all files non-linearly
    f.seek(start1 + 0x10)
    for i in range(count):
        assert byte(f) == 1 #has filename
        name = trip(f)
        start = full(f)
        end = full(f)
        back = f.tell() + 4 #I'm ignoring hashes, warning
        f.seek(start2 + 8 + (name * 4))
        name = getstr(f).split("/")
        print("/".join(name))
        base = ".".join(sys.argv[1].split(".")[:-1])
        path = "/".join([base] + name[:-1])
        name = name[-1]
        if not exists(path): makedirs(path)
        with open(path + "/" + name, "wb") as o:
            f.seek(start3 + start)
            o.write(f.read(end - start))
            #print("%s/%s" % (path, name))
        f.seek(back)