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43e6a43e3d
All of the removed `from __future__ import` were needed in older versions of Python (mostly 2.5.x and below) but later became mandatory in most versions of Python 3 hence are not necessary anymore. More specifically, according to __future__.py[1]: - unicode_literals is part of Python since versions 2.6.0 and 3.0.0; - print_function is part of Python since versions 2.6.0 and 3.0.0; - absolute_import is part of Python since versions 2.5.0 and 3.0.0; - division is part of Python since versions 2.2.0 and 3.0.0; Get rid of those unnecessary imports to slightly clean up the codebase. [1] https://github.com/python/cpython/blob/master/Lib/__future__.py
92 lines
2.9 KiB
Python
92 lines
2.9 KiB
Python
"""
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Copyright 2007 Free Software Foundation, Inc.
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This file is part of GNU Radio
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SPDX-License-Identifier: GPL-2.0-or-later
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"""
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from . import Actions
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from .Constants import STATE_CACHE_SIZE
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class StateCache(object):
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"""
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The state cache is an interface to a list to record data/states and to revert to previous states.
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States are recorded into the list in a circular fassion by using an index for the current state,
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and counters for the range where states are stored.
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"""
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def __init__(self, initial_state):
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"""
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StateCache constructor.
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Args:
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initial_state: the initial state (nested data)
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"""
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self.states = [None] * STATE_CACHE_SIZE #fill states
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self.current_state_index = 0
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self.num_prev_states = 0
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self.num_next_states = 0
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self.states[0] = initial_state
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self.update_actions()
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def save_new_state(self, state):
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"""
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Save a new state.
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Place the new state at the next index and add one to the number of previous states.
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Args:
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state: the new state
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"""
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self.current_state_index = (self.current_state_index + 1)%STATE_CACHE_SIZE
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self.states[self.current_state_index] = state
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self.num_prev_states = self.num_prev_states + 1
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if self.num_prev_states == STATE_CACHE_SIZE: self.num_prev_states = STATE_CACHE_SIZE - 1
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self.num_next_states = 0
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self.update_actions()
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def get_current_state(self):
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"""
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Get the state at the current index.
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Returns:
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the current state (nested data)
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"""
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self.update_actions()
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return self.states[self.current_state_index]
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def get_prev_state(self):
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"""
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Get the previous state and decrement the current index.
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Returns:
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the previous state or None
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"""
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if self.num_prev_states > 0:
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self.current_state_index = (self.current_state_index + STATE_CACHE_SIZE -1)%STATE_CACHE_SIZE
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self.num_next_states = self.num_next_states + 1
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self.num_prev_states = self.num_prev_states - 1
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return self.get_current_state()
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return None
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def get_next_state(self):
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"""
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Get the nest state and increment the current index.
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Returns:
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the next state or None
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"""
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if self.num_next_states > 0:
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self.current_state_index = (self.current_state_index + 1)%STATE_CACHE_SIZE
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self.num_next_states = self.num_next_states - 1
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self.num_prev_states = self.num_prev_states + 1
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return self.get_current_state()
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return None
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def update_actions(self):
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"""
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Update the undo and redo actions based on the number of next and prev states.
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"""
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Actions.FLOW_GRAPH_REDO.set_enabled(self.num_next_states != 0)
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Actions.FLOW_GRAPH_UNDO.set_enabled(self.num_prev_states != 0)
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