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optimize handling of surrogate pairs in toLower()/toUpper()

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high surrogate part never changes on upper/lower casing
(which tested explicitly in the qunicodetables generator),
thus we can copy the high surrogate part in the loop

Change-Id: I24642b35eea7596c6ad494f2a7bc670f10b759a8
Merge-request: 70
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@nokia.com>
Reviewed-by: Olivier
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
This commit is contained in:
Konstantin Ritt 2011-10-18 19:12:19 +02:00 committed by Qt by Nokia
parent 432a756048
commit 34be7e1625
1 changed files with 51 additions and 33 deletions
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84
src/corelib/tools/qstring.cpp
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@ -4071,6 +4071,7 @@ QString QString::simplified() const
if (from == fromEnd)
goto done;
} while (!ch.isSpace());
}
done:
*to++ = ch;
@ -4891,29 +4892,33 @@ QString QString::toLower() const
const ushort *p = d->data();
if (!p)
return *this;
if (!d->size)
return *this;
const ushort *e = d->data() + d->size;
// this avoids one out of bounds check in the loop
if (QChar(*p).isLowSurrogate())
++p;
const ushort *e = p + d->size;
// this avoids out of bounds check in the loop
while (e != p && QChar::isHighSurrogate(*(e - 1)))
--e;
const QUnicodeTables::Properties *prop;
while (p != e) {
uint c = *p;
if (QChar(c).isLowSurrogate() && QChar(*(p - 1)).isHighSurrogate())
c = QChar::surrogateToUcs4(*(p - 1), c);
const QUnicodeTables::Properties *prop = qGetProp(c);
if (QChar::isHighSurrogate(*p) && QChar::isLowSurrogate(p[1])) {
ushort high = *p++;
prop = qGetProp(QChar::surrogateToUcs4(high, *p));
} else {
prop = qGetProp(*p);
}
if (prop->lowerCaseDiff || prop->lowerCaseSpecial) {
if (QChar::isLowSurrogate(*p))
--p; // safe; diff is 0 for surrogates
QString s(d->size, Qt::Uninitialized);
memcpy(s.d->data(), d->data(), (p - d->data())*sizeof(ushort));
ushort *pp = s.d->data() + (p - d->data());
while (p < e) {
uint c = *p;
if (QChar(c).isLowSurrogate() && QChar(*(p - 1)).isHighSurrogate())
c = QChar::surrogateToUcs4(*(p - 1), c);
prop = qGetProp(c);
while (p != e) {
if (QChar::isHighSurrogate(*p) && QChar::isLowSurrogate(p[1])) {
*pp = *p++;
prop = qGetProp(QChar::surrogateToUcs4(*pp++, *p));
} else {
prop = qGetProp(*p);
}
if (prop->lowerCaseSpecial) {
int pos = pp - s.d->data();
s.resize(s.d->size + SPECIAL_CASE_MAX_LEN);
@ -4926,6 +4931,11 @@ QString QString::toLower() const
}
++p;
}
// this restores high surrogate parts eaten above, if any
while (e != d->data() + d->size)
*pp++ = *e++;
s.truncate(pp - s.d->data());
return s;
}
@ -4979,35 +4989,38 @@ QString QString::toCaseFolded() const
\sa toLower(), QLocale::toLower()
*/
QString QString::toUpper() const
{
const ushort *p = d->data();
if (!p)
return *this;
if (!d->size)
return *this;
const ushort *e = d->data() + d->size;
// this avoids one out of bounds check in the loop
if (QChar(*p).isLowSurrogate())
++p;
const ushort *e = p + d->size;
// this avoids out of bounds check in the loop
while (e != p && QChar::isHighSurrogate(*(e - 1)))
--e;
const QUnicodeTables::Properties *prop;
while (p != e) {
uint c = *p;
if (QChar(c).isLowSurrogate() && QChar(*(p - 1)).isHighSurrogate())
c = QChar::surrogateToUcs4(*(p - 1), c);
const QUnicodeTables::Properties *prop = qGetProp(c);
if (QChar::isHighSurrogate(*p) && QChar::isLowSurrogate(p[1])) {
ushort high = *p++;
prop = qGetProp(QChar::surrogateToUcs4(high, *p));
} else {
prop = qGetProp(*p);
}
if (prop->upperCaseDiff || prop->upperCaseSpecial) {
if (QChar::isLowSurrogate(*p))
--p; // safe; diff is 0 for surrogates
QString s(d->size, Qt::Uninitialized);
memcpy(s.d->data(), d->data(), (p - d->data())*sizeof(ushort));
ushort *pp = s.d->data() + (p - d->data());
while (p < e) {
uint c = *p;
if (QChar(c).isLowSurrogate() && QChar(*(p - 1)).isHighSurrogate())
c = QChar::surrogateToUcs4(*(p - 1), c);
prop = qGetProp(c);
while (p != e) {
if (QChar::isHighSurrogate(*p) && QChar::isLowSurrogate(p[1])) {
*pp = *p++;
prop = qGetProp(QChar::surrogateToUcs4(*pp++, *p));
} else {
prop = qGetProp(*p);
}
if (prop->upperCaseSpecial) {
int pos = pp - s.d->data();
s.resize(s.d->size + SPECIAL_CASE_MAX_LEN);
@ -5020,6 +5033,11 @@ QString QString::toUpper() const
}
++p;
}
// this restores high surrogate parts eaten above, if any
while (e != d->data() + d->size)
*pp++ = *e++;
s.truncate(pp - s.d->data());
return s;
}