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Issue #7632: Fix a problem with _Py_dg_strtod that could lead to

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crashes in debug builds, for certain long numeric strings
corresponding to subnormal values.
This commit is contained in:
Mark Dickinson 2010-01-12 22:23:56 +00:00
parent efa45f35b5
commit 8efef5ce9f
3 changed files with 26 additions and 11 deletions
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26
Python/dtoa.c
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@ -1142,7 +1142,7 @@ bigcomp(U *rv, const char *s0, BCinfo *bc)
dsign = bc->dsign;
nd = bc->nd;
nd0 = bc->nd0;
p5 = nd + bc->e0 - 1;
p5 = nd + bc->e0;
speccase = 0;
if (rv->d == 0.) { /* special case: value near underflow-to-zero */
/* threshold was rounded to zero */
@ -1227,17 +1227,21 @@ bigcomp(U *rv, const char *s0, BCinfo *bc)
}
}
/* Now b/d = exactly half-way between the two floating-point values */
/* on either side of the input string. Compute first digit of b/d. */
if (!(dig = quorem(b,d))) {
b = multadd(b, 10, 0); /* very unlikely */
if (b == NULL) {
Bfree(d);
return -1;
}
dig = quorem(b,d);
/* Now 10*b/d = exactly half-way between the two floating-point values
on either side of the input string. If b >= d, round down. */
if (cmp(b, d) >= 0) {
dd = -1;
goto ret;
}
/* Compute first digit of 10*b/d. */
b = multadd(b, 10, 0);
if (b == NULL) {
Bfree(d);
return -1;
}
dig = quorem(b, d);
assert(dig < 10);
/* Compare b/d with s0 */