Wander Wonder .FLD Unpack v1

import os
import struct
import glob
specfile = 'fldfilespec.csv' #constant value
specpath = 'fldpathspec.csv' #constant value

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

#The workhorse function. It will unpack an .fld file like the name says.
def unpack_fld(filename):
    print 'Unpacking {}:'.format(filename) #User message
    filedata = get_data(filename)          #Get data
    indextablestart = struct.unpack('<I',filedata[0x8:0xC])[0]  #Find index table start position
    number_of_files = struct.unpack('<I',filedata[0xC:0x10])[0] #Find number of files in archive

    if filedata[0x14] == '\x00': #Case 1: No path info. This is only true for wander.fld.
        path = ''
    else:                       #Case 2: There is path info.
        path = filedata[0x14:filedata.find('\x00',0x14)]   #Find path info
        if os.path.exists(path[:-1]) == False:             #Make a directory if there isn't already one
            os.mkdir(path[:-1])
#Builds up the SPECPATH file, which will eventually contain path info for all .fld files
#The SPECPATH file is used by the fld packing program when it runs later
    with open(specpath,'ab') as f:
        f.write(filename + ',' + path + '\r\n') #Append the .fld filename and path to SPECPATH file

#pos is the position counter
    pos = indextablestart   #Jump the position counter to the start of the index table
    for x in range(number_of_files):    #Does these steps a number of times equal to the number of files in the archive
        fname = filedata[pos:pos+12]    #Find filename data for this file
        while fname[-1] == '\x00':      #Strip out null characters from the filename
            fname = fname[:-1]          #Deletes the last character (if it's a null)
        pos += 12           #Jump the position counter to the file offset data
        fpos = struct.unpack('<I',filedata[pos:pos+4])[0]   #Get the offset data
        pos += 4            #Jump the position counter to the file size data
        fsize = struct.unpack('<I',filedata[pos:pos+4])[0]  #Get the file size data
        pos += 4            #Jump the position counter to the file name for the next file
        print 'Filename: {}, Size: {}'.format(fname, fsize)     #Print message for user
        with open(path + fname,'wb') as f:  #Save the file using offset and size data previous found, and with the proper path
            f.write(filedata[fpos:fpos+fsize])
#Builds up the SPECFILE file, which will eventually contain file list info for all .fld files
#The SPECFILE file is used by the fld packing program when it runs later
        with open(specfile,'ab') as f:      #Append the .fld filename and sub-filename to SPECFILE file
            f.write(filename + ',' + fname + '\r\n')
    print ''    #Spacing line prints when finished processing each .fld file

#Blanks out the SPECFILE and SPECPATH files when the program starts
with open(specfile,'wb') as f:
    f.write('')
with open(specpath,'wb') as f:
    f.write('')
#Wander.fld contains other .fld files
unpack_fld('wander.fld')
#Unpacks the rest of the .fld files
for f in glob.glob('*.fld'):
    if f != 'wander.fld':
        unpack_fld(f)