Issue #14716: Change integer overflow check in unicode_writer_prepare()

to compute the limit at compile time instead of runtime. Patch writen by Serhiy
Storchaka.
This commit is contained in:
Victor Stinner 2012-05-07 13:02:44 +02:00
parent 202fdca133
commit 0576f9b4cf

View file

@ -13242,8 +13242,10 @@ unicode_writer_prepare(unicode_writer_t *writer,
newlen = writer->pos + length;
if (newlen > PyUnicode_GET_LENGTH(writer->buffer)) {
/* overallocate 25% to limit the number of resize */
if (newlen <= (PY_SSIZE_T_MAX - newlen / 4))
/* Overallocate 25% to limit the number of resize.
Check for integer overflow:
(newlen + newlen / 4) <= PY_SSIZE_T_MAX */
if (newlen <= (PY_SSIZE_T_MAX - PY_SSIZE_T_MAX / 5))
newlen += newlen / 4;
if (maxchar > writer->maxchar) {