Merged revisions 62805,62811,62841-62842,62848-62849,62853-62854 via svnmerge from

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

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  r62805 | christian.heimes | 2008-05-07 01:59:53 +0200 (Wed, 07 May 2008) | 1 line

  Re-added getbuildinfo.c solution item
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  r62811 | benjamin.peterson | 2008-05-07 04:23:43 +0200 (Wed, 07 May 2008) | 2 lines

  update .bzrignore
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  r62841 | christian.heimes | 2008-05-08 00:54:17 +0200 (Thu, 08 May 2008) | 1 line

  Replace more float hacks with correct math functions
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  r62842 | benjamin.peterson | 2008-05-08 01:11:54 +0200 (Thu, 08 May 2008) | 2 lines

  Practice EAFP, and revert 62787
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  r62848 | raymond.hettinger | 2008-05-08 06:35:20 +0200 (Thu, 08 May 2008) | 1 line

  Frozensets do not benefit from autoconversion.
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  r62849 | raymond.hettinger | 2008-05-08 06:36:12 +0200 (Thu, 08 May 2008) | 1 line

  The __all__ variable forgot to expose the gcd() function.
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  r62853 | raymond.hettinger | 2008-05-08 09:23:30 +0200 (Thu, 08 May 2008) | 1 line

  Fix-up the enumerate type example and move it to the end.
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  r62854 | ronald.oussoren | 2008-05-08 12:34:39 +0200 (Thu, 08 May 2008) | 3 lines

  Fix for issue 1770190: platform.mac_ver() now returns the right
  version on OSX 10.4.10
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1 files changed, 7 insertions, 7 deletions

diff --git a/Lib/json/encoder.py b/Lib/json/encoder.py
index 4cb3660..fa744c9 100644
--- a/Lib/json/encoder.py
+++ b/Lib/json/encoder.py
@@ -2,6 +2,7 @@
 """
 
 import re
+import math
 
 try:
     from _json import encode_basestring_ascii as c_encode_basestring_ascii
@@ -25,20 +26,19 @@ ESCAPE_DCT = {
 for i in range(0x20):
     ESCAPE_DCT.setdefault(chr(i), '\\u{0:04x}'.format(i))
 
-# Assume this produces an infinity on all machines (probably not guaranteed)
-INFINITY = float('1e66666')
 FLOAT_REPR = repr
 
 def floatstr(o, allow_nan=True):
     # Check for specials.  Note that this type of test is processor- and/or
     # platform-specific, so do tests which don't depend on the internals.
 
-    if o != o:
+    if math.isnan(o):
         text = 'NaN'
-    elif o == INFINITY:
-        text = 'Infinity'
-    elif o == -INFINITY:
-        text = '-Infinity'
+    elif math.isinf(o):
+        if math.copysign(1., o) == 1.:
+            text = 'Infinity'
+        else:
+            text = '-Infinity'
     else:
         return FLOAT_REPR(o)