source: vendor/python/2.5/Tools/unicode/gencodec.py

""" Unicode Mapping Parser and Codec Generator.

This script parses Unicode mapping files as available from the Unicode
site (ftp://ftp.unicode.org/Public/MAPPINGS/) and creates Python codec
modules from them. The codecs use the standard character mapping codec
to actually apply the mapping.

Synopsis: gencodec.py dir codec_prefix

All files in dir are scanned and those producing non-empty mappings
will be written to <codec_prefix><mapname>.py with <mapname> being the
first part of the map's filename ('a' in a.b.c.txt) converted to
lowercase with hyphens replaced by underscores.

The tool also writes marshalled versions of the mapping tables to the
same location (with .mapping extension).

Written by Marc-Andre Lemburg ([email protected]).

(c) Copyright CNRI, All Rights Reserved. NO WARRANTY.
(c) Copyright Guido van Rossum, 2000.

Table generation:
(c) Copyright Marc-Andre Lemburg, 2005.
    Licensed to PSF under a Contributor Agreement.

"""#"

import re, os, time, marshal, codecs

# Maximum allowed size of charmap tables
MAX_TABLE_SIZE = 8192

# Standard undefined Unicode code point
UNI_UNDEFINED = unichr(0xFFFE)

mapRE = re.compile('((?:0x[0-9a-fA-F]+\+?)+)'
                   '\s+'
                   '((?:(?:0x[0-9a-fA-Z]+|<[A-Za-z]+>)\+?)*)'
                   '\s*'
                   '(#.+)?')

def parsecodes(codes,
               len=len, filter=filter,range=range):

    """ Converts code combinations to either a single code integer
        or a tuple of integers.

        meta-codes (in angular brackets, e.g. <LR> and <RL>) are
        ignored.

        Empty codes or illegal ones are returned as None.

    """
    if not codes:
        return None
    l = codes.split('+')
    if len(l) == 1:
        return int(l[0],16)
    for i in range(len(l)):
        try:
            l[i] = int(l[i],16)
        except ValueError:
            l[i] = None
    l = filter(lambda x: x is not None, l)
    if len(l) == 1:
        return l[0]
    else:
        return tuple(l)

def readmap(filename):

    f = open(filename,'r')
    lines = f.readlines()
    f.close()
    enc2uni = {}
    identity = []
    unmapped = range(256)

    # UTC mapping tables per convention don't include the identity
    # mappings for code points 0x00 - 0x1F and 0x7F, unless these are
    # explicitly mapped to different characters or undefined
    for i in range(32) + [127]:
        identity.append(i)
        unmapped.remove(i)
        enc2uni[i] = (i, 'CONTROL CHARACTER')

    for line in lines:
        line = line.strip()
        if not line or line[0] == '#':
            continue
        m = mapRE.match(line)
        if not m:
            #print '* not matched: %s' % repr(line)
            continue
        enc,uni,comment = m.groups()
        enc = parsecodes(enc)
        uni = parsecodes(uni)
        if comment is None:
            comment = ''
        else:
            comment = comment[1:].strip()
        if enc < 256:
            if enc in unmapped:
                unmapped.remove(enc)
            if enc == uni:
                identity.append(enc)
            enc2uni[enc] = (uni,comment)
        else:
            enc2uni[enc] = (uni,comment)

    # If there are more identity-mapped entries than unmapped entries,
    # it pays to generate an identity dictionary first, and add explicit
    # mappings to None for the rest
    if len(identity) >= len(unmapped):
        for enc in unmapped:
            enc2uni[enc] = (None, "")
        enc2uni['IDENTITY'] = 256

    return enc2uni

def hexrepr(t, precision=4):

    if t is None:
        return 'None'
    try:
        len(t)
    except:
        return '0x%0*X' % (precision, t)
    try:
        return '(' + ', '.join(['0x%0*X' % (precision, item)
                                for item in t]) + ')'
    except TypeError, why:
        print '* failed to convert %r: %s' % (t, why)
        raise

def python_mapdef_code(varname, map, comments=1, precisions=(2, 4)):

    l = []
    append = l.append
    if map.has_key("IDENTITY"):
        append("%s = codecs.make_identity_dict(range(%d))" %
               (varname, map["IDENTITY"]))
        append("%s.update({" % varname)
        splits = 1
        del map["IDENTITY"]
        identity = 1
    else:
        append("%s = {" % varname)
        splits = 0
        identity = 0

    mappings = map.items()
    mappings.sort()
    i = 0
    key_precision, value_precision = precisions
    for mapkey, mapvalue in mappings:
        mapcomment = ''
        if isinstance(mapkey, tuple):
            (mapkey, mapcomment) = mapkey
        if isinstance(mapvalue, tuple):
            (mapvalue, mapcomment) = mapvalue
        if mapkey is None:
            continue
        if (identity and
            mapkey == mapvalue and
            mapkey < 256):
            # No need to include identity mappings, since these
            # are already set for the first 256 code points.
            continue
        key = hexrepr(mapkey, key_precision)
        value = hexrepr(mapvalue, value_precision)
        if mapcomment and comments:
            append('    %s: %s,\t#  %s' % (key, value, mapcomment))
        else:
            append('    %s: %s,' % (key, value))
        i += 1
        if i == 4096:
            # Split the definition into parts to that the Python
            # parser doesn't dump core
            if splits == 0:
                append('}')
            else:
                append('})')
            append('%s.update({' % varname)
            i = 0
            splits = splits + 1
    if splits == 0:
        append('}')
    else:
        append('})')

    return l

def python_tabledef_code(varname, map, comments=1, key_precision=2):

    l = []
    append = l.append
    append('%s = (' % varname)

    # Analyze map and create table dict
    mappings = map.items()
    mappings.sort()
    table = {}
    maxkey = 0
    if map.has_key('IDENTITY'):
        for key in range(256):
            table[key] = (key, '')
        maxkey = 255
        del map['IDENTITY']
    for mapkey, mapvalue in mappings:
        mapcomment = ''
        if isinstance(mapkey, tuple):
            (mapkey, mapcomment) = mapkey
        if isinstance(mapvalue, tuple):
            (mapvalue, mapcomment) = mapvalue
        if mapkey is None:
            continue
        table[mapkey] = (mapvalue, mapcomment)
        if mapkey > maxkey: