"""Filename matching with shell patterns.

fnmatch(FILENAME, PATTERN) matches according to the local convention.
fnmatchcase(FILENAME, PATTERN) always takes case in account.

The functions operate by translating the pattern into a regular
expression. They cache the compiled regular expressions for speed.

The function translate(PATTERN) returns a regular expression
corresponding to PATTERN. (It does not compile it.)
"""

import re

__all__ = ["filter", "fnmatch", "fnmatchcase", "translate"]

_cache = {}
_MAXCACHE = 100

def _purge():
"""Clear the pattern cache"""
_cache.clear()

def fnmatch(name, pat):
"""Test whether FILENAME matches PATTERN.

Patterns are Unix shell style:

* matches everything
? matches any single character
[seq] matches any character in seq
[!seq] matches any char not in seq

An initial period in FILENAME is not special.
Both FILENAME and PATTERN are first case-normalized
if the operating system requires it.
If you don't want this, use fnmatchcase(FILENAME, PATTERN).
"""

import os
name = os.path.normcase(name)
pat = os.path.normcase(pat)
return fnmatchcase(name, pat)

def filter(names, pat):
"""Return the subset of the list NAMES that match PAT"""
import os,posixpath
result=[]
pat=os.path.normcase(pat)
if not pat in _cache:
res = translate(pat)
if len(_cache) >= _MAXCACHE:
_cache.clear()
_cache[pat] = re.compile(res)
match=_cache[pat].match
if os.path is posixpath:
# normcase on posix is NOP. Optimize it away from the loop.
for name in names:
if match(name):
result.append(name)
else:
for name in names:
if match(os.path.normcase(name)):
result.append(name)
return result

def fnmatchcase(name, pat):
"""Test whether FILENAME matches PATTERN, including case.

This is a version of fnmatch() which doesn't case-normalize
its arguments.
"""

if not pat in _cache:
res = translate(pat)
if len(_cache) >= _MAXCACHE:
_cache.clear()
_cache[pat] = re.compile(res)
return _cache[pat].match(name) is not None

def translate(pat):
"""Translate a shell PATTERN to a regular expression.

There is no way to quote meta-characters.
"""

i, n = 0, len(pat)
res = ''
while i < n:
c = pat[i]
i = i+1
if c == '*':
res = res + '.*'
elif c == '?':
res = res + '.'
elif c == '[':
j = i
if j < n and pat[j] == '!':
j = j+1
if j < n and pat[j] == ']':
j = j+1
while j < n and pat[j] != ']':
j = j+1
if j >= n:
res = res + '\\['
else:
stuff = pat[i:j].replace('\\','\\\\')
i = j+1
if stuff[0] == '!':
stuff = '^' + stuff[1:]
elif stuff[0] == '^':
stuff = '\\' + stuff
res = '%s[%s]' % (res, stuff)
else:
res = res + re.escape(c)
return res + '\Z(?ms)'