lowobservable.oec/oec/display.py
2019-09-09 21:01:58 -05:00

314 lines
7.6 KiB
Python

"""
oec.display
~~~~~~~~~~~
"""
from collections import namedtuple
import logging
from sortedcontainers import SortedSet
_ASCII_CHAR_MAP = {
'>': 0x08,
'<': 0x09,
'[': 0x0a,
']': 0x0b,
')': 0x0c,
'(': 0x0d,
'}': 0x0e,
'{': 0x0f,
# 0x10 - A real space?
'=': 0x11,
'\'': 0x12,
'"': 0x13,
'/': 0x14,
'\\': 0x15,
'|': 0x16,
'¦': 0x17,
'?': 0x18,
'!': 0x19,
'$': 0x1a,
'¢': 0x1b,
'£': 0x1c,
'¥': 0x1d,
# 0x1e - A P/T looking symbol
# 0x1f - A intertwined parens symbol
'0': 0x20,
'1': 0x21,
'2': 0x22,
'3': 0x23,
'4': 0x24,
'5': 0x25,
'6': 0x26,
'7': 0x27,
'8': 0x28,
'9': 0x29,
'ß': 0x2a,
'§': 0x2b,
'#': 0x2c,
'@': 0x2d,
'%': 0x2e,
'_': 0x2f,
'&': 0x30,
'-': 0x31,
'.': 0x32,
',': 0x33,
':': 0x34,
'+': 0x35,
'¬': 0x36,
'¯': 0x37, # ???
'°': 0x38,
# 0x39 - Accent?
'^': 0x3a, # More like an accent
'~': 0x3b, # More like an accent
'¨': 0x3c,
# 0x3d - Accute accent?
# 0x3e - Opposite of accute accent?
# 0x3f - A more extreme comma?
'a': 0x80,
'b': 0x81,
'c': 0x82,
'd': 0x83,
'e': 0x84,
'f': 0x85,
'g': 0x86,
'h': 0x87,
'i': 0x88,
'j': 0x89,
'k': 0x8a,
'l': 0x8b,
'm': 0x8c,
'n': 0x8d,
'o': 0x8e,
'p': 0x8f,
'q': 0x90,
'r': 0x91,
's': 0x92,
't': 0x93,
'u': 0x94,
'v': 0x95,
'w': 0x96,
'x': 0x97,
'y': 0x98,
'z': 0x99,
'æ': 0x9a,
'ø': 0x9b,
'å': 0x9c,
'ç': 0x9d,
# 0x9e - Semi colon with top line
# 0x9f - Asterisk with top line
'A': 0xa0,
'B': 0xa1,
'C': 0xa2,
'D': 0xa3,
'E': 0xa4,
'F': 0xa5,
'G': 0xa6,
'H': 0xa7,
'I': 0xa8,
'J': 0xa9,
'K': 0xaa,
'L': 0xab,
'M': 0xac,
'N': 0xad,
'O': 0xae,
'P': 0xaf,
'Q': 0xb0,
'R': 0xb1,
'S': 0xb2,
'T': 0xb3,
'U': 0xb4,
'V': 0xb5,
'W': 0xb6,
'X': 0xb7,
'Y': 0xb8,
'Z': 0xb9,
'Æ': 0xba,
'Ø': 0xbb,
'Å': 0xbc,
'Ç': 0xbd,
';': 0xbe,
'*': 0xbf
}
_EBCDIC_CHAR_MAP = {ascii_character.encode('cp500')[0]: byte for ascii_character, byte in _ASCII_CHAR_MAP.items()}
ASCII_CHAR_MAP = [_ASCII_CHAR_MAP.get(character, 0x00) for character in map(chr, range(256))]
EBCDIC_CHAR_MAP = [_EBCDIC_CHAR_MAP.get(character, 0x00) for character in range(256)]
def encode_ascii_character(character):
"""Map an ASCII character to a terminal display character."""
if character > 255:
return 0x00
return ASCII_CHAR_MAP[character]
def encode_ebcdic_character(character):
"""Map an EBCDIC character to a terminal display character."""
if character > 255:
return 0x00
return EBCDIC_CHAR_MAP[character]
def encode_string(string, errors='replace'):
"""Map a string to terminal display characters."""
return bytes([encode_ascii_character(character) for character
in string.encode('ascii', errors)])
# Does not include the status line row.
Dimensions = namedtuple('Dimensions', ['rows', 'columns'])
class Display:
def __init__(self, interface, dimensions):
self.logger = logging.getLogger(__name__)
self.interface = interface
self.dimensions = dimensions
(rows, columns) = self.dimensions
self.buffer = bytearray(rows * columns)
self.dirty = SortedSet()
self.address_counter = None
self.status_line = StatusLine(self.interface, columns)
def move_cursor(self, index=None, row=None, column=None, force_load=False):
"""Load the address counter."""
address = self._calculate_address(index=index, row=row, column=column)
# TODO: Verify that the address is within range - exclude status line.
if address == self.address_counter and not force_load:
return False
self.interface.offload_load_address_counter(address)
self.address_counter = address
return True
def buffered_write(self, byte, index=None, row=None, column=None):
if index is None:
if row is None or column is None:
raise ValueError('Either index or row and column is required')
index = self._get_index(row, column)
# TODO: Verify that index is within range.
if self.buffer[index] == byte:
return False
self.buffer[index] = byte
self.dirty.add(index)
return True
def flush(self):
for (start_index, end_index) in self._get_dirty_ranges():
self._flush_range(start_index, end_index)
def clear(self, clear_status_line=False):
"""Clear the screen."""
(rows, columns) = self.dimensions
if clear_status_line:
address = 0
repeat = ((rows + 1) * columns) - 1
else:
address = columns
repeat = (rows * columns) - 1
self.interface.offload_write(b'\x00', address=address, repeat=repeat)
# Update the buffer and dirty indicators to reflect the cleared screen.
for index in range(rows * columns):
self.buffer[index] = 0x00
self.dirty.clear()
self.move_cursor(row=0, column=0, force_load=True)
def _get_index(self, row, column):
return (row * self.dimensions.columns) + column
def _calculate_address(self, index=None, row=None, column=None):
if index is not None:
return self.dimensions.columns + index
if row is not None and column is not None:
return self.dimensions.columns + self._get_index(row, column)
raise ValueError('Either index or row and column is required')
def _calculate_address_after_write(self, address, count):
address += count
(rows, columns) = self.dimensions
# TODO: Determine the correct behavior here...
if self.address_counter >= self._calculate_address((rows * columns) - 1):
return None
return address
def _get_dirty_ranges(self):
if not self.dirty:
return []
# TODO: Implement multiple ranges with optimization.
return [(self.dirty[0], self.dirty[-1])]
def _flush_range(self, start_index, end_index):
if self.logger.isEnabledFor(logging.DEBUG):
self.logger.debug(f'Flushing changes for range {start_index}-{end_index}')
data = self.buffer[start_index:end_index+1]
address = self._calculate_address(start_index)
try:
self.interface.offload_write(data, address=address if address != self.address_counter else None)
except Exception as error:
# TODO: This could leave the address_counter incorrect.
self.logger.error(f'Offload write error: {error}', exc_info=error)
self.address_counter = self._calculate_address_after_write(address, len(data))
for index in range(start_index, end_index + 1):
self.dirty.discard(index)
return self.address_counter
# TODO: add validation of column and data length for write() - must be inside status line
class StatusLine:
def __init__(self, interface, columns):
self.interface = interface
self.columns = columns
def write(self, column, data):
self.interface.offload_write(data, address=column, restore_original_address=True)
def write_string(self, column, string):
self.write(column, encode_string(string))
def write_keyboard_modifiers(self, modifiers):
indicators = bytearray(1)
if modifiers.is_shift():
indicators[0] = 0xda
else:
indicators[0] = 0x00
self.write(35, indicators)