octal to unicode and beyond the infinite

octal_to_unicode.py

"""
I received a file that had octal characters as ascii. Needed to map them to latin-1 unicode and be able to go back again to latin-1 octal.
Might not be completely general, but it works for me.

E.g., 

name = 'Duchy of Zweibr\\374cken'
octalchar_to_unicode(name)
unicode_to_octalchar(octalchar_to_unicode(name))
http://www.utoronto.ca/web/HTMLdocs/NewHTML/iso_table.html
http://www.utf8-chartable.de/unicode-utf8-table.pl?number=1024&utf8=dec
"""
import re

def unicode_to_octalchar(name):
    # match anything that's not a non-ascii character
    # After 126 (base 10) is non-ASCII - not sure about decomposed characters
    # probably need to normalize first. I'm not...
    name = name.encode('latin-1')
    start = hex(127) # or chr(127)
    end = hex(255)
    pattern = '[%s-%s]+' % (chr(127), chr(255))
    parts = re.finditer(pattern, name)
    for part in parts:
        #NOTE: as soon as you make this sub, you're adding in characters
        # so you need to adjust your end points

        # convert hex to ordinal then to base 8
        sub =  "\\\\"+str(int(oct(ord(part.group()))))
        name = re.sub(pattern, sub, name, count=1)
    return name

def octalchar_to_unicode(name):
    import re
    parts = re.finditer('\\\\(\d+)', name)
    for part in parts:
        name = re.sub('\\\\(\d+)', chr(int(part.group()[1:], 8)), name, count=1)
    return name.decode('latin-1')