76 lines
2.3 KiB
Python
76 lines
2.3 KiB
Python
# Copyright 2010-2018 Google LLC
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""helpers methods for the cp_model module."""
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from __future__ import absolute_import
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from __future__ import division
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from __future__ import print_function
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import numbers
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INT_MIN = -9223372036854775808 # hardcoded to be platform independent.
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INT_MAX = 9223372036854775807
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INT32_MIN = -2147483648
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INT32_MAX = 2147483647
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def AssertIsInt64(x):
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"""Asserts that x is integer and x is in [min_int_64, max_int_64]."""
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if not isinstance(x, numbers.Integral):
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raise TypeError('Not an integer: %s' % x)
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if x < INT_MIN or x > INT_MAX:
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raise OverflowError('Does not fit in an int64: %s' % x)
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def AssertIsInt32(x):
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"""Asserts that x is integer and x is in [min_int_32, max_int_32]."""
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if not isinstance(x, numbers.Integral):
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raise TypeError('Not an integer: %s' % x)
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if x < INT32_MIN or x > INT32_MAX:
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raise OverflowError('Does not fit in an int32: %s' % x)
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def AssertIsBoolean(x):
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"""Asserts that x is 0 or 1."""
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if not isinstance(x, numbers.Integral) or x < 0 or x > 1:
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raise TypeError('Not an boolean: %s' % x)
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def CapInt64(v):
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"""Restrict v within [INT_MIN..INT_MAX] range."""
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if v > INT_MAX:
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return INT_MAX
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if v < INT_MIN:
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return INT_MIN
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return v
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def CapSub(x, y):
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"""Saturated arithmetics. Returns x - y truncated to the int64 range."""
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AssertIsInt64(x)
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AssertIsInt64(y)
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if y == 0:
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return x
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if x == y:
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if x == INT_MAX or x == INT_MIN:
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raise OverflowError(
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'Integer NaN: subtracting INT_MAX or INT_MIN to itself')
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return 0
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if x == INT_MAX or x == INT_MIN:
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return x
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if y == INT_MAX:
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return INT_MIN
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if y == INT_MIN:
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return INT_MAX
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return CapInt64(x - y)
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