From 75286739de854d761bbfcababa50d1bc6dfda12a Mon Sep 17 00:00:00 2001 From: =?utf8?q?Jo=C3=A3o=20Abecasis?= Date: Tue, 14 Feb 2012 00:02:08 +0100 Subject: [PATCH] Fix and simplify QString::mid 'position' was being used to initialize 'n' before being fully validated. To compensate for this, the code attempted to fix 'n' once 'position' was found to be invalid (negative). This would, however, also attempt to "fix" a perfectly valid value of 'n'. By fully validating 'position' beforehand we avoid this trap and can safely use it to validate and reset 'n', as needed. Arithmetic for boundary conditions of 'n' was rearranged to avoid triggering integer overflow. Removed explicit check for shared_null, as the same behaviour can be supported without it. Change-Id: Ie9bff7b8137a74f55c7dcfe629bd569045e28f3c Reviewed-by: Bradley T. Hughes --- src/corelib/tools/qstring.cpp | 20 ++----- tests/auto/corelib/tools/qstring/tst_qstring.cpp | 70 ++++++++++++++++++++++++ 2 files changed, 76 insertions(+), 14 deletions(-) diff --git a/src/corelib/tools/qstring.cpp b/src/corelib/tools/qstring.cpp index 28e8b6b..e12cf1f 100644 --- a/src/corelib/tools/qstring.cpp +++ b/src/corelib/tools/qstring.cpp @@ -3391,15 +3391,11 @@ QString QString::right(int n) const QString QString::mid(int position, int n) const { - if (d == &shared_null.str || position > d->size) + if (position > d->size) return QString(); - if (n < 0) - n = d->size - position; - if (position < 0) { - n += position; + if (position < 0) position = 0; - } - if (n + position > d->size) + if (n < 0 || n > d->size - position) n = d->size - position; if (position == 0 && n == d->size) return *this; @@ -8061,15 +8057,11 @@ QStringRef QString::rightRef(int n) const QStringRef QString::midRef(int position, int n) const { - if (d == &shared_null.str || position > d->size) + if (position > d->size) return QStringRef(); - if (n < 0) - n = d->size - position; - if (position < 0) { - n += position; + if (position < 0) position = 0; - } - if (n + position > d->size) + if (n < 0 || n > d->size - position) n = d->size - position; return QStringRef(this, position, n); } diff --git a/tests/auto/corelib/tools/qstring/tst_qstring.cpp b/tests/auto/corelib/tools/qstring/tst_qstring.cpp index 37d80af..7dd801b 100644 --- a/tests/auto/corelib/tools/qstring/tst_qstring.cpp +++ b/tests/auto/corelib/tools/qstring/tst_qstring.cpp @@ -1429,16 +1429,51 @@ void tst_QString::mid() QVERIFY(a.mid(9999).isNull()); QVERIFY(a.mid(9999,1).isNull()); + QCOMPARE(a.mid(-1, 6), QString("ABCDEF")); + QCOMPARE(a.mid(-100, 6), QString("ABCDEF")); + QVERIFY(a.mid(INT_MAX).isNull()); + QVERIFY(a.mid(INT_MAX, INT_MAX).isNull()); + QCOMPARE(a.mid(-5, INT_MAX), a); + QCOMPARE(a.mid(-1, INT_MAX), a); + QCOMPARE(a.mid(0, INT_MAX), a); + QCOMPARE(a.mid(1, INT_MAX), QString("BCDEFGHIEfGEFG")); + QCOMPARE(a.mid(5, INT_MAX), QString("FGHIEfGEFG")); + QVERIFY(a.mid(20, INT_MAX).isNull()); + QCOMPARE(a.mid(-1, -1), a); + QString n; QVERIFY(n.mid(3,3).isNull()); QVERIFY(n.mid(0,0).isNull()); QVERIFY(n.mid(9999,0).isNull()); QVERIFY(n.mid(9999,1).isNull()); + QVERIFY(n.mid(-1, 6).isNull()); + QVERIFY(n.mid(-100, 6).isNull()); + QVERIFY(n.mid(INT_MAX).isNull()); + QVERIFY(n.mid(INT_MAX, INT_MAX).isNull()); + QVERIFY(n.mid(-5, INT_MAX).isNull()); + QVERIFY(n.mid(-1, INT_MAX).isNull()); + QVERIFY(n.mid(0, INT_MAX).isNull()); + QVERIFY(n.mid(1, INT_MAX).isNull()); + QVERIFY(n.mid(5, INT_MAX).isNull()); + QVERIFY(n.mid(20, INT_MAX).isNull()); + QVERIFY(n.mid(-1, -1).isNull()); + QString x = "Nine pineapples"; QCOMPARE(x.mid(5, 4), QString("pine")); QCOMPARE(x.mid(5), QString("pineapples")); + QCOMPARE(x.mid(-1, 6), QString("Nine p")); + QCOMPARE(x.mid(-100, 6), QString("Nine p")); + QVERIFY(x.mid(INT_MAX).isNull()); + QVERIFY(x.mid(INT_MAX, INT_MAX).isNull()); + QCOMPARE(x.mid(-5, INT_MAX), x); + QCOMPARE(x.mid(-1, INT_MAX), x); + QCOMPARE(x.mid(0, INT_MAX), x); + QCOMPARE(x.mid(1, INT_MAX), QString("ine pineapples")); + QCOMPARE(x.mid(5, INT_MAX), QString("pineapples")); + QVERIFY(x.mid(20, INT_MAX).isNull()); + QCOMPARE(x.mid(-1, -1), x); } void tst_QString::midRef() @@ -1455,16 +1490,51 @@ void tst_QString::midRef() QVERIFY(a.midRef(9999).toString().isEmpty()); QVERIFY(a.midRef(9999,1).toString().isEmpty()); + QCOMPARE(a.midRef(-1, 6).toString(), QString("ABCDEF")); + QCOMPARE(a.midRef(-100, 6).toString(), QString("ABCDEF")); + QVERIFY(a.midRef(INT_MAX).isNull()); + QVERIFY(a.midRef(INT_MAX, INT_MAX).isNull()); + QCOMPARE(a.midRef(-5, INT_MAX).toString(), a); + QCOMPARE(a.midRef(-1, INT_MAX).toString(), a); + QCOMPARE(a.midRef(0, INT_MAX).toString(), a); + QCOMPARE(a.midRef(1, INT_MAX).toString(), QString("BCDEFGHIEfGEFG")); + QCOMPARE(a.midRef(5, INT_MAX).toString(), QString("FGHIEfGEFG")); + QVERIFY(a.midRef(20, INT_MAX).isNull()); + QCOMPARE(a.midRef(-1, -1).toString(), a); + QString n; QVERIFY(n.midRef(3,3).toString().isEmpty()); QVERIFY(n.midRef(0,0).toString().isEmpty()); QVERIFY(n.midRef(9999,0).toString().isEmpty()); QVERIFY(n.midRef(9999,1).toString().isEmpty()); + QVERIFY(n.midRef(-1, 6).isNull()); + QVERIFY(n.midRef(-100, 6).isNull()); + QVERIFY(n.midRef(INT_MAX).isNull()); + QVERIFY(n.midRef(INT_MAX, INT_MAX).isNull()); + QVERIFY(n.midRef(-5, INT_MAX).isNull()); + QVERIFY(n.midRef(-1, INT_MAX).isNull()); + QVERIFY(n.midRef(0, INT_MAX).isNull()); + QVERIFY(n.midRef(1, INT_MAX).isNull()); + QVERIFY(n.midRef(5, INT_MAX).isNull()); + QVERIFY(n.midRef(20, INT_MAX).isNull()); + QVERIFY(n.midRef(-1, -1).isNull()); + QString x = "Nine pineapples"; QCOMPARE(x.midRef(5, 4).toString(), QString("pine")); QCOMPARE(x.midRef(5).toString(), QString("pineapples")); + QCOMPARE(x.midRef(-1, 6).toString(), QString("Nine p")); + QCOMPARE(x.midRef(-100, 6).toString(), QString("Nine p")); + QVERIFY(x.midRef(INT_MAX).isNull()); + QVERIFY(x.midRef(INT_MAX, INT_MAX).isNull()); + QCOMPARE(x.midRef(-5, INT_MAX).toString(), x); + QCOMPARE(x.midRef(-1, INT_MAX).toString(), x); + QCOMPARE(x.midRef(0, INT_MAX).toString(), x); + QCOMPARE(x.midRef(1, INT_MAX).toString(), QString("ine pineapples")); + QCOMPARE(x.midRef(5, INT_MAX).toString(), QString("pineapples")); + QVERIFY(x.midRef(20, INT_MAX).isNull()); + QCOMPARE(x.midRef(-1, -1).toString(), x); } void tst_QString::stringRef() -- 2.7.4