#! /usr/bin/env python

import sys, re, os, tempfile
def main():
	"""
%s [conversion type] [files]

Converts line breaks of input file(s) regardless of input
file type. The type of conversion is specified according 
to the first argument. Replace [files] with - to read stdin.

Possible values for first argument:
-d    DOS
-m    Macintosh
-u    UNIX
-n    remove line breaks

Other options:
-h    print this help message
-v    print version info
"""
	
	version='$Id: lconv,v 1.2 2004/11/30 21:11:43 nghoffma Exp $'

	# match either \r or \n or both in any order
	anyending = re.compile(r'\r\n|\r|\n')
	
	leDict = {'d':'\r\n', 'u':'\n', 'm':'\r', 'n':''}
	
	msgDict = {'d':r'Converting %s to DOS format (\r\n)', 
	'u':r'Converting %s to UNIX format (\n)', 
	'm':r'Converting %s to Macintosh format (\r)', 
	'n':r'Removing line breaks from %s'}
	
	args = sys.argv[1:]

	try:
		option = args[0].lower().replace('-','')
		if option == 'v':
			sys.exit(version)
		elif option in 'h help'.split() or len(args) < 2:
			raise IndexError
		newending = leDict[option]
	except IndexError:
		sys.exit(main.__doc__ % os.path.split(sys.argv[0])[-1])	
	except KeyError:
		sys.exit('%s: bad conversion type (choose from d, m, u, n)' % args[0])
	
	# special case for stdin
	if ''.join(args[1:]).strip() == '-':
		sys.stdout.write(anyending.sub(newending, sys.stdin.read()))
	
	else:
		for arg in args[1:]:
			tempname = tempfile.mktemp()
			try:
				infile = open(arg,'rb')
				outfile = open(tempname,'wb')
				# convert the line endings and write the result
				outfile.write(anyending.sub(newending, infile.read()))
				infile.close()
				outfile.close()
				os.rename(tempname, arg)
			except (IOError, OSError), msg:
				print msg
				continue
			
			print msgDict[option] % arg

main()