Merged revisions 58211-58220 via svnmerge from

svn+ssh://pythondev@svn.python.org/python/trunk

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  r58211 | facundo.batista | 2007-09-19 19:53:25 +0200 (Wed, 19 Sep 2007) | 4 lines


  Issue #1772851.  Optimization of __hash__ to behave better for big big
  numbers.
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  r58216 | raymond.hettinger | 2007-09-20 05:03:43 +0200 (Thu, 20 Sep 2007) | 1 line

  Fit nits
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  r58217 | georg.brandl | 2007-09-20 10:44:59 +0200 (Thu, 20 Sep 2007) | 2 lines

  alternate -> alternative.
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  r58218 | georg.brandl | 2007-09-20 18:06:07 +0200 (Thu, 20 Sep 2007) | 2 lines

  Patch #1541463: optimize performance of cgi.FieldStorage operations.
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  r58219 | georg.brandl | 2007-09-20 18:45:27 +0200 (Thu, 20 Sep 2007) | 2 lines

  #1176: document that string methods don't take keyword args.
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  r58220 | thomas.wouters | 2007-09-20 19:35:10 +0200 (Thu, 20 Sep 2007) | 4 lines


  Try harder to stay within the 79-column limit. There's still two places that go (way) over, but those are harder to fix without suffering in readability.
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1 files changed, 11 insertions, 4 deletions

diff --git a/Lib/decimal.py b/Lib/decimal.py
index d7bd127..ffe6e9e 100644
--- a/Lib/decimal.py
+++ b/Lib/decimal.py
@@ -786,10 +786,17 @@ class Decimal(object):
             if self._isnan():
                 raise TypeError('Cannot hash a NaN value.')
             return hash(str(self))
-        i = int(self)
-        if self == Decimal(i):
-            return hash(i)
-        assert self.__bool__()   # '-0' handled by integer case
+        if not self:
+            return 0
+        if self._isinteger():
+            op = _WorkRep(self.to_integral_value())
+            # to make computation feasible for Decimals with large
+            # exponent, we use the fact that hash(n) == hash(m) for
+            # any two nonzero integers n and m such that (i) n and m
+            # have the same sign, and (ii) n is congruent to m modulo
+            # 2**64-1.  So we can replace hash((-1)**s*c*10**e) with
+            # hash((-1)**s*c*pow(10, e, 2**64-1).
+            return hash((-1)**op.sign*op.int*pow(10, op.exp, 2**64-1))
         return hash(str(self.normalize()))
 
     def as_tuple(self):