Recursive SARCExtract (goes through all ones in a directory, but not subdirectories)

SARCExtractR.py

from struct import pack, unpack
from os import mkdir, makedirs, listdir
from os.path import exists
import sys

def half(en, f):
    return unpack("%sH" % en, f.read(2))[0]

def full(en, f):
    return unpack("%sI" % en, f.read(4))[0]

def getstr(f):
    ret = "";char = f.read(1)
    while char != "\x00":
        ret += char
        char = f.read(1)
    return ret

def warn(a, b):
    try: assert a == True
    except Exception, err:
        sys.stderr.write("WARNING: " + b)

def err(a, b):
    try: assert a == True
    except Exception, err:
        sys.stderr.write("ERROR: " + b)
        sys.exit(1)

def gethash(name, multiplier):
    result = 0
    for i in range(len(name)):
        result  = ord(name[i]) + (result * multiplier)
        result &= 0xFFFFFFFF
    return result

def getext(magic):
    if   magic == "BNTX": #Switch Texture
        return "bntx"
    elif magic == "BNSH": #Switch Shader ???
        return "bnsh"
    elif magic == "FLAN": #Wii U Layout Animation
        return "bflan"
    elif magic == "FLYT": #Wii U Layout Metadata
        return "bflyt"
    else:
        return "bin"

if __name__ == "__main__":
    print("SARCExtract vIDK by NWPlayer123")
    print("written June 12th, 17th 2017")
    print("hopefully futureproof this time")
    print("")
    for name in listdir("."):
        if name.endswith(".sarc"):
            with open(name, "rb") as f:
                #-------------------------------------------------------------
                err(f.read(4) == b"SARC", "not a SARC file")
                f.seek(6) #need to read endian first before 0x14
                en = ["<", ">"][unpack(">H", f.read(2))[0] & 1]
                f.seek(4) #now we can check it w/endian
                err(half(en, f) == 0x14, "header size != 0x14, not supp.")
                f.seek(0, 2) #end of file, verify correct size
                size = f.tell()
                f.seek(8) #stored offset
                err(full(en, f) == size, "filesize mismatch, truncated?")
                start = full(en, f) #of raw data
                #err(full(en, f) == 0x100, "number at 0x10 is not 256, ?????")
                f.seek(4, 1) # ^^^ was giving issues
                #-------------------------------------------------------------
                err(f.read(4) == b"SFAT", "magic mismatch, SFAT missing?")
                err(half(en, f) == 12, "SFAT header size != 12, not supp.")
                count = half(en, f)
                multi = full(en, f)
                warn(multi == 0x65, "hash mult. not 0x65, may not be supp.")
                attr = [unpack("%s4I" % en, f.read(16)) for i in range(count)]
                #-------------------------------------------------------------
                err(f.read(4) == b"SFNT", "magic mismatch, SFNT missing?")
                err(half(en, f) == 8, "SFNT header size != 8, not supp.")
                err(half(en, f) == 0, "SFNT header half 2 != 0, ?????")
                SFNT = f.tell()
                base = ".".join(name.split(".")[:-1]) #remove extension
                if not exists(base): mkdir(base)
                #-------------------------------------------------------------
                print("%s%s      %s" % ("NAME".ljust(80), "SIZE", "HASH"))
                unknown = 0
                for i in range(count):
                    if attr[i][1] & 0x01000000: #file has name
                        f.seek(SFNT + ((attr[i][1] & 0xFFFF) * 4))
                        name = getstr(f)
                        err(gethash(name, multi) == attr[i][0],
                                   "name hash failed: " + name)
                    else:
                        f.seek(start + attr[i][2])
                        name = "UNKNOWN%d.%s" % (unknown, getext(f.read(4)))
                        unknown += 1
                    if len(name) < 80:
                        print("%s%08X  %08X" % (name.ljust(80), attr[i][3]\
                                                  - attr[i][2], attr[i][0]))
                    else:
                        trun = "..." + name[-76:] + " "
                        print("%s%08X  %08X" % (trun, attr[i][3]-attr[i][2],\
                                                                 attr[i][0]))
                    if "/" in name: #assume all are encoded this way
                        path = base + "/" + "/".join(name.split("/")[:-1])
                    else:
                        path = base
                    if not exists(path): makedirs(path)
                    with open(base + "/" + name, "wb") as o:
                        f.seek(start + attr[i][2])
                        o.write(f.read(attr[i][3]-attr[i][2]))