polysh/terminal_size.py

   1 # from http://pdos.csail.mit.edu/~cblake/cls/cls.py
   2 # License in http://pdos.csail.mit.edu/~cblake/cls/cls_py_LICENSE reproduced
   3 # thereafter:
   4 # I, Charles Blake, hereby relinquish all rights to the functions
   5 # terminal_size() and ioctl_GWINSZ() in file cls.py, located in this
   6 # same code directory to the maximum extent applicable by this notice.
   7 #
   8 # These functions are provided "as is" and without any expressed or implied
   9 # warranties, including, without limitation, the implied warranties of
  10 # merchantibility and fitness for a particular purpose.
  11 #
  12 # It would be nice (but not necessary) to give me an artistic license credit
  13 # somewhere in the licensing materials of any derivative product.
  14
  15
  16 import os
  17
  18 def _ioctl_GWINSZ(fd):                  #### TABULATION FUNCTIONS
  19     try:                                ### Discover terminal width
  20         import fcntl
  21         import termios
  22         import struct
  23         cr = struct.unpack('hh', fcntl.ioctl(fd, termios.TIOCGWINSZ, '1234'))
  24     except:
  25         return
  26     return cr
  27
  28 def terminal_size():                    ### decide on *some* terminal size
  29     """Return (lines, columns)."""
  30     cr = _ioctl_GWINSZ(0) or _ioctl_GWINSZ(1) or _ioctl_GWINSZ(2) # try open fds
  31     if not cr:                                                  # ...then ctty
  32         try:
  33             fd = os.open(os.ctermid(), os.O_RDONLY)
  34             cr = _ioctl_GWINSZ(fd)
  35             os.close(fd)
  36         except:
  37             pass
  38         if not cr:                            # env vars or finally defaults
  39             try:
  40                 cr = os.environ['LINES'], os.environ['COLUMNS']
  41             except:
  42                 cr = 25, 80
  43     return int(cr[1]), int(cr[0])         # reverse rows, cols