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# GNU Solfege - free ear training software
# Copyright (C) 2000, 2001, 2002, 2003, 2004, 2007, 2008 Tom Cato Amundsen
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
class History:
def __init__(self):
self.m_list = []
self.m_idx = -1
self.m_lock = 0
def add(self, data):
"""
Add history at the current position. Data after the current
position is lost.
"""
if self.m_lock:
return
# First we remove if necessary
self.m_list = self.m_list[:self.m_idx + 1]
# we don't want duplicate entries in the history
if not self.m_list or self.m_list[-1][0] != data:
self.m_list.append([data, None])
self.m_idx = self.m_idx + 1
def set_adj_of_current(self, adj):
if self.m_lock:
raise Exception("Called set_adj_of_current when locked.")
self.m_list[self.m_idx][1] = adj
def back(self):
if self.m_idx > 0:
self.m_idx = self.m_idx - 1
def forward(self):
if self.m_idx + 1 < len(self.m_list):
self.m_idx = self.m_idx + 1
def get_current(self):
if self.m_idx >= 0:
return self.m_list[self.m_idx]
def lock(self):
"Do not record any history"
self.m_lock = 1
def unlock(self):
self.m_lock = 0
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