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QByteArray/QString: use qregisteruint for storing the moving hash 

There are some architectures where
  sizeof(qregisteruint) > sizeof(size_t)
so this could be a minor performance improvement.

Change-Id: If05cb740b64f42eba21efffd17cf30c3ae5bd88f
Reviewed-by: Ahmad Samir <a.samirh78@gmail.com>
bb10
Thiago Macieira 2024-05-13 16:40:00 -07:00 committed by Ahmad Samir
parent 7886d0adbb
commit 817c0c33e1
3 changed files with 14 additions and 14 deletions
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8
src/corelib/text/qbytearray.cpp
View File

@ -2716,10 +2716,10 @@ static qsizetype lastIndexOfHelper(const char *haystack, qsizetype l, const char
const char *end = haystack;
haystack += from;
const auto ol_minus_1 = std::size_t(ol - 1);
const qregisteruint ol_minus_1 = ol - 1;
const char *n = needle + ol_minus_1;
const char *h = haystack + ol_minus_1;
std::size_t hashNeedle = 0, hashHaystack = 0;
qregisteruint hashNeedle = 0, hashHaystack = 0;
qsizetype idx;
for (idx = 0; idx < ol; ++idx) {
hashNeedle = ((hashNeedle<<1) + *(n-idx));
@ -2731,8 +2731,8 @@ static qsizetype lastIndexOfHelper(const char *haystack, qsizetype l, const char
if (hashHaystack == hashNeedle && memcmp(needle, haystack, ol) == 0)
return haystack - end;
--haystack;
if (ol_minus_1 < sizeof(std::size_t) * CHAR_BIT)
hashHaystack -= std::size_t(*(haystack + ol)) << ol_minus_1;
if (ol_minus_1 < sizeof(ol_minus_1) * CHAR_BIT)
hashHaystack -= qregisteruint(*(haystack + ol)) << ol_minus_1;
hashHaystack <<= 1;
}
return -1;

8
src/corelib/text/qbytearraymatcher.cpp
View File

@ -270,8 +270,8 @@ qsizetype qFindByteArray(const char *haystack0, qsizetype l, qsizetype from,
*/
const char *haystack = haystack0 + from;
const char *end = haystack0 + (l - sl);
const auto sl_minus_1 = std::size_t(sl - 1);
std::size_t hashNeedle = 0, hashHaystack = 0;
const qregisteruint sl_minus_1 = sl - 1;
qregisteruint hashNeedle = 0, hashHaystack = 0;
qsizetype idx;
for (idx = 0; idx < sl; ++idx) {
hashNeedle = ((hashNeedle<<1) + needle[idx]);
@ -285,8 +285,8 @@ qsizetype qFindByteArray(const char *haystack0, qsizetype l, qsizetype from,
&& memcmp(needle, haystack, sl) == 0)
return haystack - haystack0;
if (sl_minus_1 < sizeof(std::size_t) * CHAR_BIT)
hashHaystack -= std::size_t(*haystack) << sl_minus_1;
if (sl_minus_1 < sizeof(sl_minus_1) * CHAR_BIT)
hashHaystack -= qregisteruint(*haystack) << sl_minus_1;
hashHaystack <<= 1;
++haystack;
}

12
src/corelib/text/qstring.cpp
View File

@ -63,8 +63,8 @@
#endif
#define REHASH(a) \
if (sl_minus_1 < sizeof(std::size_t) * CHAR_BIT) \
hashHaystack -= std::size_t(a) << sl_minus_1; \
if (sl_minus_1 < sizeof(sl_minus_1) * CHAR_BIT) \
hashHaystack -= decltype(hashHaystack)(a) << sl_minus_1; \
hashHaystack <<= 1
QT_BEGIN_NAMESPACE
@ -183,10 +183,10 @@ static qsizetype qLastIndexOf(Haystack haystack0, qsizetype from,
const auto needle = needle0.data();
const auto *end = haystack;
haystack += from;
const std::size_t sl_minus_1 = sl ? sl - 1 : 0;
const qregisteruint sl_minus_1 = sl ? sl - 1 : 0;
const auto *n = needle + sl_minus_1;
const auto *h = haystack + sl_minus_1;
std::size_t hashNeedle = 0, hashHaystack = 0;
qregisteruint hashNeedle = 0, hashHaystack = 0;
if (cs == Qt::CaseSensitive) {
for (qsizetype idx = 0; idx < sl; ++idx) {
@ -9905,8 +9905,8 @@ qsizetype QtPrivate::findString(QStringView haystack0, qsizetype from, QStringVi
const char16_t *needle = needle0.utf16();
const char16_t *haystack = haystack0.utf16() + from;
const char16_t *end = haystack0.utf16() + (l - sl);
const std::size_t sl_minus_1 = sl - 1;
std::size_t hashNeedle = 0, hashHaystack = 0;
const qregisteruint sl_minus_1 = sl - 1;
qregisteruint hashNeedle = 0, hashHaystack = 0;
qsizetype idx;
if (cs == Qt::CaseSensitive) {