import sys
import tty
import termios
import fcntl
import os
from . import keys
def get_symbol():
''' Read a symbol, which can be a single byte character or a multibyte string'''
ch = read_char()
ch_code = ord(ch)
# check for multibyte string
if ch_code == keys.ESC:
ch = read_char_no_blocking()
if ch == '':
# ESC key pressed
return keys.ESC
elif ch != 'O' and ch != '[':
return ord(ch)
else:
ch = read_char_no_blocking()
if ch == 'A':
return keys.UP
elif ch == 'B':
return keys.DOWN
elif ch == 'C':
return keys.RIGHT
elif ch == 'D':
return keys.LEFT
return ch_code
def read_char():
''' Read a character '''
fd = sys.stdin.fileno()
old_settings = termios.tcgetattr(fd)
try:
tty.setraw(fd, termios.TCSADRAIN)
ch = sys.stdin.read(1)
finally:
termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
return ch
def read_char_no_blocking():
''' Read a character in nonblocking mode, if no characters are present in the buffer, return an empty string '''
fd = sys.stdin.fileno()
old_settings = termios.tcgetattr(fd)
old_flags = fcntl.fcntl(fd, fcntl.F_GETFL)
try:
tty.setraw(fd, termios.TCSADRAIN)
fcntl.fcntl(fd, fcntl.F_SETFL, old_flags | os.O_NONBLOCK)
return sys.stdin.read(1)
except IOError as e:
ErrorNumber = e[0]
# IOError with ErrorNumber 11(35 in Mac) is thrown when there is nothing to read(Resource temporarily unavailable)
if (sys.platform.startswith("linux") and ErrorNumber != 11) or (sys.platform == "darwin" and ErrorNumber != 35):
raise
return ""
finally:
fcntl.fcntl(fd, fcntl.F_SETFL, old_flags)
termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
