X360 GoD XCP Unpacker

import os
import zlib
import io
import struct
import sys
import hashlib

def decodeTitleId(titleId):
    tidData=struct.unpack(">2sH",bytes.fromhex(titleId))
    return "%s-%d" % (tidData[0].decode(),tidData[1])

def generateGODName(titleId,mediaId,disc,numDiscs):
    sha1=hashlib.sha1()
    sha1.update(bytes.fromhex(titleId))
    sha1.update(bytes.fromhex(mediaId))
    sha1.update(disc.to_bytes())
    sha1.update(numDiscs.to_bytes())

    return sha1.hexdigest().upper()[:20]

def extractGODXCP(fname,contentDir):
    def decompressBlock(f):
        out=io.BytesIO()
        decomp=zlib.decompressobj()
        while not decomp.eof:
            data=f.read(0x8000)
            decdata=decomp.decompress(data)
            out.write(decdata)

        extraSize=len(decomp.unused_data)
        f.seek(-extraSize,1)
        return out.getvalue()

    def decompressPayload(f,f2,outsize,fsize):
        while f2.tell()!=outsize and f.tell()!=fsize:
            data=decompressBlock(f)
            writeSize=min(len(data),outsize-f2.tell())
            f2.write(data[:writeSize])

        return data[writeSize:]

    f=open(fname,"rb")
    f.seek(0,2)
    fsize=f.tell()
    f.seek(0)

    # Write header.
    hdr=io.BytesIO()
    extraData=decompressPayload(f,hdr,0xb000,fsize)

    hdr.seek(0x32c)
    contentId=hdr.read(0x14).hex()
    hdr.seek(0x344)
    contentType=hdr.read(0x04).hex()
    hdr.seek(0x354)
    mediaId=hdr.read(0x04).hex()
    version=hdr.read(0x04).hex()
    baseVersion=hdr.read(0x04).hex()
    titleId=hdr.read(0x04).hex()
    titleIdTxt=decodeTitleId(titleId)
    hdr.seek(0x366)
    disc=int.from_bytes(hdr.read(0x01))
    numDiscs=int.from_bytes(hdr.read(0x01))
    hdr.seek(0x39d)
    numDataFiles=int.from_bytes(hdr.read(0x04))
    totalDataSize=int.from_bytes(hdr.read(0x08))
    hdr.seek(0x411)
    contentName=hdr.read(0x100).decode("utf-16be").split("\0",1)[0]
    hdr.seek(0x1691)
    gameName=hdr.read(0x80).decode("utf-16be").split("\0",1)[0]

    print("Title: %s\nTitle ID: %s / %s\nMedia ID: %s\nVersion: %s\nBase version: %s\nContent ID: %s\nContent type: %s" %
          (contentName,titleId,titleIdTxt,mediaId,version,baseVersion,contentId,contentType))

    outdir=os.path.join(contentDir,titleId.upper(),contentType.upper())
    os.makedirs(outdir,exist_ok=True)
    godName=generateGODName(titleId,mediaId,disc,numDiscs)
    outpath=os.path.join(outdir,godName)

    f2=open(outpath,"wb")
    f2.write(hdr.getvalue())
    f2.close()

    outdir=outpath+".data"
    os.makedirs(outdir,exist_ok=True)
    writtenSize=0

    for i in range(numDataFiles):
        outpath=os.path.join(outdir,"Data%04d" % (i))
        print(outpath)
        f2=open(outpath,"wb")
        if extraData: f2.write(extraData)
        extraData=decompressPayload(f,f2,0xa290000,fsize)
        writtenSize+=f2.tell()
        f2.close()

        if writtenSize==totalDataSize:
            break

    f.close()

if __name__=="__main__":
    extractGODXCP(sys.argv[1],"content")