#! /usr/bin/env python3

"""Python utility to print MD5 checksums of argument files.
"""


bufsize = 8096
fnfilter = None
rmode = 'rb'

usage = """
usage: md5sum.py [-b] [-t] [-l] [-s bufsize] [file ...]
-b : read files in binary mode (default)
-t : read files in text mode (you almost certainly don't want this!)
-l : print last pathname component only
-s bufsize: read buffer size (default %d)
file ... : files to sum; '-' or no files means stdin
""" % bufsize

import io
import sys
import os
import getopt
from hashlib import md5

def sum(*files):
 sts = 0
 if files and isinstance(files[-1], io.IOBase):
 out, files = files[-1], files[:-1]
 else:
 out = sys.stdout
 if len(files) == 1 and not isinstance(files[0], str):
 files = files[0]
 for f in files:
 if isinstance(f, str):
 if f == '-':
 sts = printsumfp(sys.stdin, '<stdin>', out) or sts
 else:
 sts = printsum(f, out) or sts
 else:
 sts = sum(f, out) or sts
 return sts

def printsum(filename, out=sys.stdout):
 try:
 fp = open(filename, rmode)
 except IOError as msg:
 sys.stderr.write('%s: Can\'t open: %s\n' % (filename, msg))
 return 1
 if fnfilter:
 filename = fnfilter(filename)
 sts = printsumfp(fp, filename, out)
 fp.close()
 return sts

def printsumfp(fp, filename, out=sys.stdout):
 m = md5()
 try:
 while 1:
 data = fp.read(bufsize)
 if not data:
 break
 if isinstance(data, str):
 data = data.encode(fp.encoding)
 m.update(data)
 except IOError as msg:
 sys.stderr.write('%s: I/O error: %s\n' % (filename, msg))
 return 1
 out.write('%s %s\n' % (m.hexdigest(), filename))
 return 0

def main(args = sys.argv[1:], out=sys.stdout):
 global fnfilter, rmode, bufsize
 try:
 opts, args = getopt.getopt(args, 'blts:')
 except getopt.error as msg:
 sys.stderr.write('%s: %s\n%s' % (sys.argv[0], msg, usage))
 return 2
 for o, a in opts:
 if o == '-l':
 fnfilter = os.path.basename
 elif o == '-b':
 rmode = 'rb'
 elif o == '-t':
 rmode = 'r'
 elif o == '-s':
 bufsize = int(a)
 if not args:
 args = ['-']
 return sum(args, out)

if __name__ == '__main__' or __name__ == sys.argv[0]:
 sys.exit(main(sys.argv[1:], sys.stdout))