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Merged revisions 77614-77616,77663 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk ........ r77614 | mark.dickinson | 2010-01-20 17:36:31 +0000 (Wed, 20 Jan 2010) | 5 lines Various dtoa.c cleanups. 1. Despagghetify _Py_dg_strtod parsing code and exit points. 2. Simplify bigcomp comparison loop. 3. Don't set ERANGE on _Py_dg_strtod underflow (it was set inconsistently anyway). 4. Remove unused dsign field from BCinfo struct. ........ r77615 | mark.dickinson | 2010-01-20 18:02:41 +0000 (Wed, 20 Jan 2010) | 1 line Don't try to put a value into a NULL pointer. ........ r77616 | mark.dickinson | 2010-01-20 21:23:25 +0000 (Wed, 20 Jan 2010) | 1 line Additional explanatory comments for _Py_dg_strtod. ........ r77663 | mark.dickinson | 2010-01-21 17:02:53 +0000 (Thu, 21 Jan 2010) | 1 line Additional testcases for strtod. ........
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‎Lib/test/test_strtod.py‎

Lines changed: 95 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -100,6 +100,49 @@ def check_strtod(self, s):
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"Incorrectly rounded str->float conversion for {}: "
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"expected {}, got {}".format(s, expected, got))
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def test_short_halfway_cases(self):
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# exact halfway cases with a small number of significant digits
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for k in 0, 5, 10, 15, 20:
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# upper = smallest integer >= 2**54/5**k
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upper = -(-2**54//5**k)
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# lower = smallest odd number >= 2**53/5**k
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lower = -(-2**53//5**k)
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if lower % 2 == 0:
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lower += 1
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for i in range(10 * TEST_SIZE):
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# Select a random odd n in [2**53/5**k,
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# 2**54/5**k). Then n * 10**k gives a halfway case
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# with small number of significant digits.
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n, e = random.randrange(lower, upper, 2), k
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# Remove any additional powers of 5.
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while n % 5 == 0:
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n, e = n // 5, e + 1
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assert n % 10 in (1, 3, 7, 9)
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# Try numbers of the form n * 2**p2 * 10**e, p2 >= 0,
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# until n * 2**p2 has more than 20 significant digits.
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digits, exponent = n, e
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while digits < 10**20:
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s = '{}e{}'.format(digits, exponent)
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self.check_strtod(s)
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# Same again, but with extra trailing zeros.
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s = '{}e{}'.format(digits * 10**40, exponent - 40)
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self.check_strtod(s)
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digits *= 2
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# Try numbers of the form n * 5**p2 * 10**(e - p5), p5
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# >= 0, with n * 5**p5 < 10**20.
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digits, exponent = n, e
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while digits < 10**20:
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s = '{}e{}'.format(digits, exponent)
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self.check_strtod(s)
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# Same again, but with extra trailing zeros.
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s = '{}e{}'.format(digits * 10**40, exponent - 40)
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self.check_strtod(s)
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digits *= 5
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exponent -= 1
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def test_halfway_cases(self):
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# test halfway cases for the round-half-to-even rule
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for i in range(1000):
@@ -164,10 +207,10 @@ def test_underflow_boundary(self):
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self.check_strtod(s)
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def test_bigcomp(self):
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DIG10 = 10**50
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for i in range(1000):
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for j in range(TEST_SIZE):
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digits = random.randrange(DIG10)
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for ndigs in 5, 10, 14, 15, 16, 17, 18, 19, 20, 40, 41, 50:
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dig10 = 10**ndigs
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for i in range(100 * TEST_SIZE):
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digits = random.randrange(dig10)
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exponent = random.randrange(-400, 400)
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s = '{}e{}'.format(digits, exponent)
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self.check_strtod(s)
@@ -254,11 +297,59 @@ def test_particular(self):
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# demonstration that original fix for issue 7632 bug 1 was
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# buggy; the exit condition was too strong
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'247032822920623295e-341',
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# demonstrate similar problem to issue 7632 bug1: crash
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# with 'oversized quotient in quorem' message.
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'99037485700245683102805043437346965248029601286431e-373',
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'99617639833743863161109961162881027406769510558457e-373',
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'98852915025769345295749278351563179840130565591462e-372',
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'99059944827693569659153042769690930905148015876788e-373',
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'98914979205069368270421829889078356254059760327101e-372',
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# issue 7632 bug 5: the following 2 strings convert differently
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'1000000000000000000000000000000000000000e-16',
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'10000000000000000000000000000000000000000e-17',
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# issue 7632 bug 7
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'991633793189150720000000000000000000000000000000000000000e-33',
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# And another, similar, failing halfway case
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'4106250198039490000000000000000000000000000000000000000e-38',
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# issue 7632 bug 8: the following produced 10.0
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'10.900000000000000012345678912345678912345',
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# exercise exit conditions in bigcomp comparison loop
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'2602129298404963083833853479113577253105939995688e2',
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'260212929840496308383385347911357725310593999568896e0',
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'26021292984049630838338534791135772531059399956889601e-2',
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'260212929840496308383385347911357725310593999568895e0',
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'260212929840496308383385347911357725310593999568897e0',
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'260212929840496308383385347911357725310593999568996e0',
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'260212929840496308383385347911357725310593999568866e0',
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# 2**53
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'9007199254740992.00',
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# 2**1024 - 2**970: exact overflow boundary. All values
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# smaller than this should round to something finite; any value
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# greater than or equal to this one overflows.
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'179769313486231580793728971405303415079934132710037' #...
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'826936173778980444968292764750946649017977587207096' #...
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'330286416692887910946555547851940402630657488671505' #...
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'820681908902000708383676273854845817711531764475730' #...
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'270069855571366959622842914819860834936475292719074' #...
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'168444365510704342711559699508093042880177904174497792',
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# 2**1024 - 2**970 - tiny
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'179769313486231580793728971405303415079934132710037' #...
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'826936173778980444968292764750946649017977587207096' #...
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'330286416692887910946555547851940402630657488671505' #...
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'820681908902000708383676273854845817711531764475730' #...
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'270069855571366959622842914819860834936475292719074' #...
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'168444365510704342711559699508093042880177904174497791.999',
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# 2**1024 - 2**970 + tiny
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'179769313486231580793728971405303415079934132710037' #...
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'826936173778980444968292764750946649017977587207096' #...
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'330286416692887910946555547851940402630657488671505' #...
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'820681908902000708383676273854845817711531764475730' #...
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'270069855571366959622842914819860834936475292719074' #...
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'168444365510704342711559699508093042880177904174497792.001',
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# 1 - 2**-54, +-tiny
350+
'999999999999999944488848768742172978818416595458984375e-54',
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'9999999999999999444888487687421729788184165954589843749999999e-54',
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'9999999999999999444888487687421729788184165954589843750000001e-54',
262353
]
263354
for s in test_strings:
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self.check_strtod(s)

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