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The constructor from tuple was way too permissive: it allowed bad

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coefficient numbers, floats in the sign, and other details that
generated directly the wrong number in the best case, or triggered
misfunctionality in the alorithms.

Test cases added for these issues. Thanks Mark Dickinson.
This commit is contained in:
Facundo Batista 2007-10-19 19:25:57 +00:00
parent 91ac42243c
commit 9b5e23148b
2 changed files with 63 additions and 10 deletions
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46
Lib/decimal.py
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@ -562,20 +562,46 @@ class Decimal(object):
# tuple/list conversion (possibly from as_tuple())
if isinstance(value, (list,tuple)):
if len(value) != 3:
raise ValueError('Invalid arguments')
if value[0] not in (0,1):
raise ValueError('Invalid sign')
for digit in value[1]:
if not isinstance(digit, (int,long)) or digit < 0:
raise ValueError("The second value in the tuple must be "
"composed of non negative integer elements.")
raise ValueError('Invalid tuple size in creation of Decimal '
'from list or tuple. The list or tuple '
'should have exactly three elements.')
# process sign. The isinstance test rejects floats
if not (isinstance(value[0], (int, long)) and value[0] in (0,1)):
raise ValueError("Invalid sign. The first value in the tuple "
"should be an integer; either 0 for a "
"positive number or 1 for a negative number.")
self._sign = value[0]
self._int = tuple(value[1])
if value[2] in ('F','n','N'):
if value[2] == 'F':
# infinity: value[1] is ignored
self._int = (0,)
self._exp = value[2]
self._is_special = True
else:
self._exp = int(value[2])
# process and validate the digits in value[1]
digits = []
for digit in value[1]:
if isinstance(digit, (int, long)) and 0 <= digit <= 9:
# skip leading zeros
if digits or digit != 0:
digits.append(digit)
else:
raise ValueError("The second value in the tuple must "
"be composed of integers in the range "
"0 through 9.")
if value[2] in ('n', 'N'):
# NaN: digits form the diagnostic
self._int = tuple(digits)
self._exp = value[2]
self._is_special = True
elif isinstance(value[2], (int, long)):
# finite number: digits give the coefficient
self._int = tuple(digits or [0])
self._exp = value[2]
self._is_special = False
else:
raise ValueError("The third value in the tuple must "
"be an integer, or one of the "
"strings 'F', 'n', 'N'.")
return self
if isinstance(value, float):