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QString: remove a try/catch from replace_helper()

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I think it was there because of of the QChar array allocated on the
heap (to store a copy of the "after" string when it's part of 'this'
string) and the subsequent ::free() call; instead split some code to a
static helper, and store the copy in a QVarLengthArray; the latter has
SSO, so it'll only heap-allocate if needed, and will take care of
deleting the data.

Remove now unused textCopy() method.

Change-Id: Iaf29d19ebd40d24948f0859d80f45e4c16e5bbce
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Marc Mutz <marc.mutz@qt.io>
This commit is contained in:
Ahmad Samir 2022-11-20 21:14:14 +02:00
parent 9532339788
commit 3575d2d028
1 changed files with 54 additions and 64 deletions
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118
src/corelib/text/qstring.cpp
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@ -3502,78 +3502,68 @@ QString &QString::remove(QChar ch, Qt::CaseSensitivity cs)
\sa remove()
*/
namespace { // helpers for replace and its helper:
QChar *textCopy(const QChar *start, qsizetype len)
static void do_replace_helper(QString &str, size_t *indices, qsizetype nIndices, qsizetype blen,
const QChar *after, qsizetype alen)
{
const size_t size = len * sizeof(QChar);
QChar *const copy = static_cast<QChar *>(::malloc(size));
Q_CHECK_PTR(copy);
::memcpy(copy, start, size);
return copy;
if (blen == alen) {
// replace in place
str.detach();
for (qsizetype i = 0; i < nIndices; ++i)
memcpy(str.data_ptr().data() + indices[i], after, alen * sizeof(QChar));
} else if (alen < blen) {
// replace from front
str.detach();
size_t to = indices[0];
if (alen)
memcpy(str.data_ptr().data()+to, after, alen*sizeof(QChar));
to += alen;
size_t movestart = indices[0] + blen;
for (qsizetype i = 1; i < nIndices; ++i) {
qsizetype msize = indices[i] - movestart;
if (msize > 0) {
memmove(str.data_ptr().data() + to, str.data_ptr().data() + movestart, msize * sizeof(QChar));
to += msize;
}
if (alen) {
memcpy(str.data_ptr().data() + to, after, alen * sizeof(QChar));
to += alen;
}
movestart = indices[i] + blen;
}
qsizetype msize = str.data_ptr().size - movestart;
if (msize > 0)
memmove(str.data_ptr().data() + to, str.data_ptr().data() + movestart, msize * sizeof(QChar));
str.resize(str.data_ptr().size - nIndices*(blen-alen));
} else {
// replace from back
qsizetype adjust = nIndices*(alen-blen);
qsizetype newLen = str.data_ptr().size + adjust;
qsizetype moveend = str.data_ptr().size;
str.resize(newLen);
while (nIndices) {
--nIndices;
qsizetype movestart = indices[nIndices] + blen;
qsizetype insertstart = indices[nIndices] + nIndices*(alen-blen);
qsizetype moveto = insertstart + alen;
memmove(str.data_ptr().data() + moveto, str.data_ptr().data() + movestart,
(moveend - movestart)*sizeof(QChar));
memcpy(str.data_ptr().data() + insertstart, after, alen * sizeof(QChar));
moveend = movestart-blen;
}
}
}
} // end namespace
static void replace_helper(QString &str, size_t *indices, qsizetype nIndices, qsizetype blen, const QChar *after, qsizetype alen)
{
// Copy after if it lies inside our own d.b area (which we could
// possibly invalidate via a realloc or modify by replacement).
QChar *afterBuffer = nullptr;
if (QtPrivate::q_points_into_range(after, str)) // Use copy in place of vulnerable original:
after = afterBuffer = textCopy(after, alen);
QT_TRY {
if (blen == alen) {
// replace in place
str.detach();
for (qsizetype i = 0; i < nIndices; ++i)
memcpy(str.data_ptr().data() + indices[i], after, alen * sizeof(QChar));
} else if (alen < blen) {
// replace from front
str.detach();
size_t to = indices[0];
if (alen)
memcpy(str.data_ptr().data()+to, after, alen*sizeof(QChar));
to += alen;
size_t movestart = indices[0] + blen;
for (qsizetype i = 1; i < nIndices; ++i) {
qsizetype msize = indices[i] - movestart;
if (msize > 0) {
memmove(str.data_ptr().data() + to, str.data_ptr().data() + movestart, msize * sizeof(QChar));
to += msize;
}
if (alen) {
memcpy(str.data_ptr().data() + to, after, alen * sizeof(QChar));
to += alen;
}
movestart = indices[i] + blen;
}
qsizetype msize = str.data_ptr()->size - movestart;
if (msize > 0)
memmove(str.data_ptr().data() + to, str.data_ptr().data() + movestart, msize * sizeof(QChar));
str.resize(str.data_ptr()->size - nIndices*(blen-alen));
} else {
// replace from back
qsizetype adjust = nIndices*(alen-blen);
qsizetype newLen = str.data_ptr().size + adjust;
qsizetype moveend = str.data_ptr().size;
str.resize(newLen);
while (nIndices) {
--nIndices;
qsizetype movestart = indices[nIndices] + blen;
qsizetype insertstart = indices[nIndices] + nIndices*(alen-blen);
qsizetype moveto = insertstart + alen;
memmove(str.data_ptr().data() + moveto, str.data_ptr().data() + movestart,
(moveend - movestart)*sizeof(QChar));
memcpy(str.data_ptr().data() + insertstart, after, alen * sizeof(QChar));
moveend = movestart-blen;
}
}
} QT_CATCH(const std::bad_alloc &) {
::free(afterBuffer);
QT_RETHROW;
if (QtPrivate::q_points_into_range(after, str)) {
const QVarLengthArray<QChar> after_copy{after, after+alen};
do_replace_helper(str, indices, nIndices, blen, after_copy.data(), after_copy.size());
} else {
do_replace_helper(str, indices, nIndices, blen, after, alen);
}
::free(afterBuffer);
}
/*!