#!/usr/bin/python
# $Id: catv,v 1.2 2019/02/22 21:53:01 friedman Exp $

# This was written to work in Python 2.5 (and possibly earlier) for ESXi 4.x,
# as well as Python 3.x for later versions of ESXi.  Thus, some contortions.

import sys
import os
import re

# The `bytes' type is not defined in python < 2.6 at all,
# and in 2.6 <= python < 3.0, it is equivalent to str.
try:
    bytes
except NameError:
    bytes = str

def to_bytes( x, encoding='iso8859-1' ): # any 8-bit encoding would do
    if bytes is not str:
        return bytes( x, encoding=encoding )
    return x

def dispchar( c ):
    n = ord( c )
    if n < 31:
        return to_bytes( '^' + chr( n + 64 ) )
    if n == 0x7f:
        return to_bytes( '^?' )
    if n > 127:
        return to_bytes( '\\{:x}'.format( n ) )
    else:
        return c

pat = re.compile( to_bytes( '([\x00-\x08\x0b-\x1f\x7f-\xff])' ))

def catv( fd ):
    stdout = sys.stdout.fileno()
    while True:
        buf = os.read( fd, 4096 )
        if len( buf ) == 0:
            return
        buf = pat.sub( lambda c: dispchar( c.group( 1 )), buf )
        os.write( stdout, buf )

if __name__ == '__main__':
    if len( sys.argv ) < 2:
        sys.argv.insert( 1, '-' )
    for filename in sys.argv[ 1: ]:
        if filename == '-':
            fd = os.dup( sys.stdin.fileno() )
        else:
            try:
                fd = os.open( filename, os.O_RDONLY )
            except (OSError, IOError):
                e = sys.exc_info()[ 1 ]
                msg = str.join( ': ', (e.filename, e.strerror) ) + '\n'
                os.write( sys.stderr.fileno(), to_bytes( msg ))
                continue
        catv( fd )
        os.close( fd )

# eof