From fb591c73661055bf48a44b4742a2399ae8dc684a Mon Sep 17 00:00:00 2001 From: Marc Mutz Date: Wed, 24 Feb 2016 14:56:36 +0100 Subject: QStringBuilder: don't allocate memory in convertFromAscii() Use new QUtf8::convertToUnicode(QChar*, const char*, int) overload instead of QString::fromUtf8(). The QUtf8 overload allocates no memory, and is therefore marked as nothrow. Using this function in convertFromAscii() allows to mark this function nothrow, too. All functions of QAbstractConcatenable can now be marked as nothrow. Since QUtf8::convertToUnicode() does not deal with lengths of -1, insert a strlen() call when the len == -1 ASCII fast path fails due to non-ASCII chars. Saves 1.1KiB in text size on optimized GCC 5.3 Linux AMD64 builds of QtCore (other libraries are compiled without exceptions, so this change should not have an effect on those). Change-Id: I7333e35844033831eae2a04203d13d9792c5d460 Reviewed-by: Olivier Goffart (Woboq GmbH) --- src/corelib/tools/qstringbuilder.cpp | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'src/corelib/tools/qstringbuilder.cpp') diff --git a/src/corelib/tools/qstringbuilder.cpp b/src/corelib/tools/qstringbuilder.cpp index eba939a413..85babbd698 100644 --- a/src/corelib/tools/qstringbuilder.cpp +++ b/src/corelib/tools/qstringbuilder.cpp @@ -39,6 +39,7 @@ #include "qstringbuilder.h" #include +#include QT_BEGIN_NAMESPACE @@ -107,7 +108,7 @@ QT_BEGIN_NAMESPACE /*! \internal */ -void QAbstractConcatenable::convertFromAscii(const char *a, int len, QChar *&out) +void QAbstractConcatenable::convertFromAscii(const char *a, int len, QChar *&out) Q_DECL_NOTHROW { if (len == -1) { if (!a) @@ -116,6 +117,7 @@ void QAbstractConcatenable::convertFromAscii(const char *a, int len, QChar *&out *out++ = QLatin1Char(*a++); if (!*a) return; + len = int(strlen(a)); } else { int i; for (i = 0; i < len && uchar(a[i]) < 0x80U; ++i) @@ -127,9 +129,7 @@ void QAbstractConcatenable::convertFromAscii(const char *a, int len, QChar *&out } // we need to complement with UTF-8 appending - QString tmp = QString::fromUtf8(a, len); - memcpy(out, reinterpret_cast(tmp.constData()), sizeof(QChar) * tmp.size()); - out += tmp.size(); + out = QUtf8::convertToUnicode(out, a, len); } QT_END_NAMESPACE -- cgit v1.2.3