Add google-endpoints to third_party/.

third_party/google-endpoints/google/api/control/money.py

+# Copyright 2016 Google Inc. All Rights Reserved.
+#
+# 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.
+
+"""money provides funcs for working with `Money` instances.
+
+:func:`check_valid` determines if a `Money` instance is valid
+:func:`add` adds two `Money` instances together
+
+"""
+
+from __future__ import absolute_import
+
+import logging
+import sys
+
+from . import messages
+
+logger = logging.getLogger(__name__)
+
+_INT64_MAX = sys.maxint
+_INT64_MIN = -sys.maxint - 1
+_BILLION = 1000000000
+MAX_NANOS = _BILLION - 1
+_MSG_3_LETTERS_LONG = 'The currency code is not 3 letters long'
+_MSG_UNITS_NANOS_MISMATCH = 'The signs of the units and nanos do not match'
+_MSG_NANOS_OOB = 'The nanos field must be between -999999999 and 999999999'
+
+
+def check_valid(money):
+    """Determine if an instance of `Money` is valid.
+
+    Args:
+      money (:class:`google.api.gen.servicecontrol_v1_messages.Money`): the
+        instance to test
+
+    Raises:
+      ValueError: if the money instance is invalid
+    """
+    if not isinstance(money, messages.Money):
+        raise ValueError('Inputs should be of type %s' % (messages.Money,))
+    currency = money.currencyCode
+    if not currency or len(currency) != 3:
+        raise ValueError(_MSG_3_LETTERS_LONG)
+    units = money.units
+    nanos = money.nanos
+    if ((units > 0) and (nanos < 0)) or ((units < 0) and (nanos > 0)):
+        raise ValueError(_MSG_UNITS_NANOS_MISMATCH)
+    if abs(nanos) > MAX_NANOS:
+        raise ValueError(_MSG_NANOS_OOB)
+
+
+def add(a, b, allow_overflow=False):
+    """Adds two instances of `Money`.
+
+    Args:
+      a (:class:`google.api.gen.servicecontrol_v1_messages.Money`): one money
+        value
+      b (:class:`google.api.gen.servicecontrol_v1_messages.Money`): another
+        money value
+      allow_overflow: determines if the addition is allowed to overflow
+
+    Return:
+      `Money`: an instance of Money
+
+    Raises:
+      ValueError: if the inputs do not have the same currency code
+      OverflowError: if the sum overflows and allow_overflow is not `True`
+    """
+    for m in (a, b):
+        if not isinstance(m, messages.Money):
+            raise ValueError('Inputs should be of type %s' % (messages.Money,))
+    if a.currencyCode != b.currencyCode:
+        raise ValueError('Money values need the same currency to be summed')
+    nano_carry, nanos_sum = _sum_nanos(a, b)
+    units_sum_no_carry = a.units + b.units
+    units_sum = units_sum_no_carry + nano_carry
+
+    # Adjust when units_sum and nanos_sum have different signs
+    if units_sum > 0 and nanos_sum < 0:
+        units_sum -= 1
+        nanos_sum += _BILLION
+    elif units_sum < 0 and nanos_sum > 0:
+        units_sum += 1
+        nanos_sum -= _BILLION
+
+    # Return the result, detecting overflow if it occurs
+    sign_a = _sign_of(a)
+    sign_b = _sign_of(b)
+    if sign_a > 0 and sign_b > 0 and units_sum >= _INT64_MAX:
+        if not allow_overflow:
+            raise OverflowError('Money addition positive overflow')
+        else:
+            return messages.Money(units=_INT64_MAX,
+                                  nanos=MAX_NANOS,
+                                  currencyCode=a.currencyCode)
+    elif (sign_a < 0 and sign_b < 0 and
+          (units_sum_no_carry <= -_INT64_MAX or units_sum <= -_INT64_MAX)):
+        if not allow_overflow:
+            raise OverflowError('Money addition negative overflow')
+        else:
+            return messages.Money(units=_INT64_MIN,
+                                  nanos=-MAX_NANOS,
+                                  currencyCode=a.currencyCode)
+    else:
+        return messages.Money(units=units_sum,
+                              nanos=nanos_sum,
+                              currencyCode=a.currencyCode)
+
+
+def _sum_nanos(a, b):
+    the_sum = a.nanos + b.nanos
+    carry = 0
+    if the_sum > _BILLION:
+        carry = 1
+        the_sum -= _BILLION
+    elif the_sum <= -_BILLION:
+        carry = -1
+        the_sum += _BILLION
+    return carry, the_sum
+
+
+def _sign_of(money):
+    """Determines the amount sign of a money instance
+
+    Args:
+      money (:class:`google.api.gen.servicecontrol_v1_messages.Money`): the
+        instance to test
+
+    Return:
+      int: 1, 0 or -1
+
+    """
+    units = money.units
+    nanos = money.nanos
+    if units:
+        if units > 0:
+            return 1
+        elif units < 0:
+            return -1
+    if nanos:
+        if nanos > 0:
+            return 1
+        elif nanos < 0:
+            return -1
+    return 0