mirror of
https://github.com/gnuradio/gnuradio-companion.git
synced 2025-12-11 13:54:07 -06:00
97 lines
3.0 KiB
Python
97 lines
3.0 KiB
Python
"""
|
|
Copyright 2007 Free Software Foundation, Inc.
|
|
This file is part of GNU Radio
|
|
|
|
SPDX-License-Identifier: GPL-2.0-or-later
|
|
|
|
"""
|
|
|
|
from . import Actions
|
|
from .Constants import STATE_CACHE_SIZE
|
|
|
|
|
|
class StateCache(object):
|
|
"""
|
|
The state cache is an interface to a list to record data/states and to revert to previous states.
|
|
States are recorded into the list in a circular fassion by using an index for the current state,
|
|
and counters for the range where states are stored.
|
|
"""
|
|
|
|
def __init__(self, initial_state):
|
|
"""
|
|
StateCache constructor.
|
|
|
|
Args:
|
|
initial_state: the initial state (nested data)
|
|
"""
|
|
self.states = [None] * STATE_CACHE_SIZE # fill states
|
|
self.current_state_index = 0
|
|
self.num_prev_states = 0
|
|
self.num_next_states = 0
|
|
self.states[0] = initial_state
|
|
self.update_actions()
|
|
|
|
def save_new_state(self, state):
|
|
"""
|
|
Save a new state.
|
|
Place the new state at the next index and add one to the number of previous states.
|
|
|
|
Args:
|
|
state: the new state
|
|
"""
|
|
self.current_state_index = (
|
|
self.current_state_index + 1) % STATE_CACHE_SIZE
|
|
self.states[self.current_state_index] = state
|
|
self.num_prev_states = self.num_prev_states + 1
|
|
if self.num_prev_states == STATE_CACHE_SIZE:
|
|
self.num_prev_states = STATE_CACHE_SIZE - 1
|
|
self.num_next_states = 0
|
|
self.update_actions()
|
|
|
|
def get_current_state(self):
|
|
"""
|
|
Get the state at the current index.
|
|
|
|
Returns:
|
|
the current state (nested data)
|
|
"""
|
|
self.update_actions()
|
|
return self.states[self.current_state_index]
|
|
|
|
def get_prev_state(self):
|
|
"""
|
|
Get the previous state and decrement the current index.
|
|
|
|
Returns:
|
|
the previous state or None
|
|
"""
|
|
if self.num_prev_states > 0:
|
|
self.current_state_index = (
|
|
self.current_state_index + STATE_CACHE_SIZE - 1) % STATE_CACHE_SIZE
|
|
self.num_next_states = self.num_next_states + 1
|
|
self.num_prev_states = self.num_prev_states - 1
|
|
return self.get_current_state()
|
|
return None
|
|
|
|
def get_next_state(self):
|
|
"""
|
|
Get the nest state and increment the current index.
|
|
|
|
Returns:
|
|
the next state or None
|
|
"""
|
|
if self.num_next_states > 0:
|
|
self.current_state_index = (
|
|
self.current_state_index + 1) % STATE_CACHE_SIZE
|
|
self.num_next_states = self.num_next_states - 1
|
|
self.num_prev_states = self.num_prev_states + 1
|
|
return self.get_current_state()
|
|
return None
|
|
|
|
def update_actions(self):
|
|
"""
|
|
Update the undo and redo actions based on the number of next and prev states.
|
|
"""
|
|
Actions.FLOW_GRAPH_REDO.set_enabled(self.num_next_states != 0)
|
|
Actions.FLOW_GRAPH_UNDO.set_enabled(self.num_prev_states != 0)
|