ED6 Decompress TEST1

# Decompression algorithm spreadsheet:
# https://docs.google.com/spreadsheets/d/1ipgx25yp0XOtf-48-5a5j78TL67fE_6a2vXCiFvcxYo/edit#gid=0
# Both lines 101 and 147 go to line 278. I couldn't figure out how these are related
# So I made everything after 278 into a subroutine (and made almost all variables globals)

import struct, os

def get_data(filename):
    totalbytes = os.path.getsize(filename)
    infile = open(filename, 'rb')
    totalfiledata = infile.read(totalbytes)
    infile.close()
    return totalfiledata

def load_flag_bits():
    global num_flag_bits, flag_bits, input_pos, filedata
    flag_bits = struct.unpack('<H',filedata[input_pos:input_pos+2])[0]
##    print 'New flag bits:   {:016b}'.format(flag_bits) #Prints flag bits
    input_pos += 2
    num_flag_bits = 0x10

def sub_0x89b11dc():
    global num_flag_bits, flag_bits, a0, a1, a2, v1, v2, s0, s1, s2, s4
    global input_pos, filedata, output, output_size
#1     -> s2 = 2
#01    -> s2 = 3
#001   -> s2 = 4
#0001  -> s2 = 5
#00001 -> s2 = 6 plus next three flag bits (a number between 0 and 7)
#00000 -> s2 = next byte of input plus 0xE
    if num_flag_bits == 0:
        load_flag_bits()
    flag_bit = flag_bits & 1
    flag_bits = flag_bits >> 1
    num_flag_bits -= 1
    s2 = 2
    if flag_bit == 0: #0x89b123c
        if num_flag_bits == 0:
            load_flag_bits()
        flag_bit = flag_bits & 1
        flag_bits = flag_bits >> 1
        num_flag_bits -= 1
        s2 = 3
        if flag_bit == 0: #0x89b12a0
            if num_flag_bits == 0:
                load_flag_bits()
            flag_bit = flag_bits & 1
            flag_bits = flag_bits >> 1
            num_flag_bits -= 1
            s2 = 4
            if flag_bit == 0: #0x89b1308
                if num_flag_bits == 0:
                    load_flag_bits()
                flag_bit = flag_bits & 1
                flag_bits = flag_bits >> 1
                num_flag_bits -= 1
                s2 = 5
                if flag_bit == 0: #0x89b1370
                    if num_flag_bits == 0:
                        load_flag_bits()
                    flag_bit = flag_bits & 1
                    flag_bits = flag_bits >> 1
                    num_flag_bits -= 1
                    if flag_bit == 0: #0x89b13d8
                        s2 = ord(filedata[input_pos])
                        input_pos += 1
                        s2 += 0xE
                    else:
                        t0 = 3
                        a2 = 0
                        while t0 != 0:
                            v0 = a2 << 1
                            a2 = v0 & 0xFFFF
                            if num_flag_bits == 0:
                                load_flag_bits()
                            v1 = flag_bits & 1
                            flag_bits = flag_bits >> 1
                            num_flag_bits -= 1
                            v1 += a2
                            t0 -= 1
                            a2 = v1 & 0xFFFF
                        s2 = a2 & 0xFFFF
                        s2 += 6
#Starting "copy from buffer" operation
#a1 is how far to go back, s2 is how much to copy
    s0 = len(output) - a1 #Where to start copying
    s4 = s2 + output_size
    v1 = 0
    if 0x3FFF0 < s4: #0x89b14b8
        return False
##    if unpacked_size < s4: #0x89b14c8
##        return False
##    if s2 >= 4: #0x89b14d0
##        v0 = len(output) - s0 #How far back to start copying
##
##        if v0 >= 4: #0x89b14e8
##            print 'Fail'
##            quit()
##            v0 = s0 + s2 #???
##            #Go to 0x89B1528 (where to start is <4 back and size >=4)
    if s2 != 0: #0x89b14f0
        a1 = 0
        while a1 != s2:
            output += output[s0]
            s0 += 1
            a1 += 1
    output_size = s4
    v1 = 0
    return True

def decompress_text(filename):
    global filedata, input_pos, num_flag_bits, flag_bits, output, output_size, \
           unpacked_size, a1, a2, a3, s2, s4, v0, v1
    filedata = get_data(filename + '.orig')
    output = ''
    output_size = 8
    output += filedata[:8]
    input_pos = 8
    num_flag_bits = 0

    #89b0df0
    while True:
        if num_flag_bits == 0:
            load_flag_bits()
        flag_bit = flag_bits & 1
        flag_bits = flag_bits >> 1
        num_flag_bits -= 1
        if flag_bit == 0: #89b0e48
            output += filedata[input_pos]
            input_pos += 1
            output_size += 1
            continue
        else: #89b0e98
            if num_flag_bits == 0:
                load_flag_bits()
            flag_bit = flag_bits & 1
            flag_bits = flag_bits >> 1
            num_flag_bits -= 1
            if flag_bit == 0: #89b0ef4
                a1 = ord(filedata[input_pos])
                input_pos += 1
                flag = sub_0x89b11dc()
                if flag:
                    continue
                else:
                    break
            else: #89b0f20
                a3 = 0x5
                a2 = 0
                while a3 != 0: #This JC is at 0x89b0fa0
                    v0 = a2 << 1 #89b0f30
                    a2 = v0 & 0xFFFF
                    if num_flag_bits == 0:
                        load_flag_bits()
                    v1 = flag_bits & 1
                    flag_bits = flag_bits >> 1
                    num_flag_bits -= 1
                    v1 += a2
                    a3 -= 1
                    a2 = v1 & 0xFFFF
                a2 = a2 << 8
                a2 += ord(filedata[input_pos])
                input_pos += 1
                if a2 == 0:
                    break
                a1 = a2
                if a2 != 1: #0x89b0fd0
                    flag = sub_0x89b11dc()
                    if flag:
                        continue
                    else:
                        break
                if num_flag_bits == 0: #0x89b0fd8
                    load_flag_bits()
                flag_bit = flag_bits & 1
                flag_bits = flag_bits >> 1
                num_flag_bits -= 1
                if flag_bit == 0: #89b101c
                    a3 = 4
                    a2 = 0
                    while a3 != 0:
                        v0 = a2 << 1
                        a2 = v0 & 0xFFFF
                        if num_flag_bits == 0: #0x89b0fd8
                            load_flag_bits()
                        v1 = flag_bits & 1
                        flag_bits = flag_bits >> 1
                        num_flag_bits -= 1
                        v1 += a2
                        a3 -= 1
                        a2 = v1 & 0xFFFF
                    s2 = a2 & 0xFFFF
                    s4 = s2 + 0xE
                    # Go to 0x89b1190
                else: #0x89b10dc
                    a3 = 4
                    a2 = 0
                    while a3 != 0:
                        v0 = a2 << 1
                        a2 = v0 & 0xFFFF
                        if num_flag_bits == 0: #0x89b0fd8
                            load_flag_bits()
                        v1 = flag_bits & 1
                        flag_bits = flag_bits >> 1
                        num_flag_bits -= 1
                        v1 += a2
                        a3 -= 1
                        a2 = v1 & 0xFFFF
                    s2 = a2 << 8
                    s2 += ord(filedata[input_pos])
                    input_pos += 1
                    s4 = s2 + 0xE
                a1 = ord(filedata[input_pos]) #0x89b1190
                input_pos += 1
                output += chr(a1)*s4
                output_size += s4
                continue
    input_pos += 4
    output_file = open(filename + '.unpack2','wb')
    output_file.write(output)
    output_file.close()

decompress_text('T_TITLE._DT')