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+# Copyright (c) 2021 PANTHEON.tech s.r.o.
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at:
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Increment utilities library."""
+
+
+class ObjIncrement():
+ """
+ An iterator class used to generate incremented values in each iteration
+ or when inc_fmt is called.
+
+ Subclasses should override:
+ _incr: when a simple '+' binary operation isn't sufficient.
+ _str_fmt: when a simple str representation of the incremented object
+ isn't the proper format.
+ """
+ def __init__(self, initial_value, increment):
+ """
+ :param initial_value: The first value to be returned.
+ :param increment: Each iteration/inc_fmt call will return the previous
+ value incremented by this.
+ :type initial_value: object supporting the '+' binary operation
+ :type increment: object supporting the '+' binary operation
+ """
+ self._value = initial_value
+ self._increment = increment
+
+ def _incr(self):
+ """
+ This function will be called in each iteration/inc_fmt call. Subclasses
+ should override this when their object is incremented differently.
+ The function must compute the next iterated value and store it in
+ self._value.
+ """
+ self._value += self._increment
+
+ def __next__(self):
+ """
+ Each iteration returns the current object and stores the incremented
+ object (which will be returned in the next iteration). The first
+ iteration returns the initial value.
+ """
+ return_value = self._value
+ self._incr()
+ return return_value
+
+ def __iter__(self):
+ return self
+
+ def _str_fmt(self):
+ """
+ The string representation is a standard string representation of the
+ incremented object. Subclasses may override this for a different
+ string representation.
+ """
+ return str(self._value)
+
+ def inc_fmt(self):
+ """
+ Return a string representation and increment the current value.
+ """
+ return_value = self._str_fmt()
+ self._incr()
+ return return_value