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Trent Mick: 

Fix overflow bug in ldexp(x, exp). The 'exp' argument maps to a C int for the
math library call [double ldexp(double, int)], however the 'd'
PyArg_ParseTuple formatter was used to yield a double, which was subsequently
cast to an int. This could overflow.

[GvR: mysteriously, on Solaris 2.7, ldexp(1, 2147483647) returns Inf
while ldexp(1, 2147483646) raises OverflowError; this seems a bug in
the math library (it also takes a real long time to compute the
Inf outcome).  Does this point to a bug in the CHECK() macro?  It
should have discovered that the result was outside the HUGE_VAL range.]
This commit is contained in:
Guido van Rossum 2000-05-08 14:29:38 +00:00
parent 23ef82ffe3
commit c554505ca1
1 changed files with 4 additions and 4 deletions
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8
Modules/mathmodule.c
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@ -196,13 +196,13 @@ math_ldexp(self, args)
PyObject *self; PyObject *self;
PyObject *args; PyObject *args;
{ {
double x, y; double x;
/* Cheat -- allow float as second argument */ int exp;
if (! PyArg_Parse(args, "(dd)", &x, &y)) if (! PyArg_Parse(args, "(di)", &x, &exp))
return NULL; return NULL;
errno = 0; errno = 0;
PyFPE_START_PROTECT("ldexp", return 0) PyFPE_START_PROTECT("ldexp", return 0)
x = ldexp(x, (int)y); x = ldexp(x, exp);
PyFPE_END_PROTECT(x) PyFPE_END_PROTECT(x)
CHECK(x); CHECK(x);
if (errno != 0) if (errno != 0)