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authorQt by Nokia <qt-info@nokia.com>2011-04-27 12:05:43 +0200
committeraxis <qt-info@nokia.com>2011-04-27 12:05:43 +0200
commit38be0d13830efd2d98281c645c3a60afe05ffece (patch)
tree6ea73f3ec77f7d153333779883e8120f82820abe /src/corelib/global/qmalloc.cpp
Initial import from the monolithic Qt.
This is the beginning of revision history for this module. If you want to look at revision history older than this, please refer to the Qt Git wiki for how to use Git history grafting. At the time of writing, this wiki is located here: http://qt.gitorious.org/qt/pages/GitIntroductionWithQt If you have already performed the grafting and you don't see any history beyond this commit, try running "git log" with the "--follow" argument. Branched from the monolithic repo, Qt master branch, at commit 896db169ea224deb96c59ce8af800d019de63f12
Diffstat (limited to 'src/corelib/global/qmalloc.cpp')
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diff --git a/src/corelib/global/qmalloc.cpp b/src/corelib/global/qmalloc.cpp
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+/****************************************************************************
+**
+** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtCore module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qplatformdefs.h"
+
+#include <stdlib.h>
+
+/*
+ Define the container allocation functions in a separate file, so that our
+ users can easily override them.
+*/
+
+QT_BEGIN_NAMESPACE
+
+void *qMalloc(size_t size)
+{
+ return ::malloc(size);
+}
+
+void qFree(void *ptr)
+{
+ ::free(ptr);
+}
+
+void *qRealloc(void *ptr, size_t size)
+{
+ return ::realloc(ptr, size);
+}
+
+void *qMallocAligned(size_t size, size_t alignment)
+{
+ return qReallocAligned(0, size, 0, alignment);
+}
+
+void *qReallocAligned(void *oldptr, size_t newsize, size_t oldsize, size_t alignment)
+{
+ // fake an aligned allocation
+ Q_UNUSED(oldsize);
+
+ void *actualptr = oldptr ? static_cast<void **>(oldptr)[-1] : 0;
+ if (alignment <= sizeof(void*)) {
+ // special, fast case
+ void **newptr = static_cast<void **>(qRealloc(actualptr, newsize + sizeof(void*)));
+ if (!newptr)
+ return 0;
+ if (newptr == actualptr) {
+ // realloc succeeded without reallocating
+ return oldptr;
+ }
+
+ *newptr = newptr;
+ return newptr + 1;
+ }
+
+ // qMalloc returns pointers aligned at least at sizeof(size_t) boundaries
+ // but usually more (8- or 16-byte boundaries).
+ // So we overallocate by alignment-sizeof(size_t) bytes, so we're guaranteed to find a
+ // somewhere within the first alignment-sizeof(size_t) that is properly aligned.
+
+ // However, we need to store the actual pointer, so we need to allocate actually size +
+ // alignment anyway.
+
+ void *real = qRealloc(actualptr, newsize + alignment);
+ if (!real)
+ return 0;
+
+ quintptr faked = reinterpret_cast<quintptr>(real) + alignment;
+ faked &= ~(alignment - 1);
+
+ void **faked_ptr = reinterpret_cast<void **>(faked);
+
+ // now save the value of the real pointer at faked-sizeof(void*)
+ // by construction, alignment > sizeof(void*) and is a power of 2, so
+ // faked-sizeof(void*) is properly aligned for a pointer
+ faked_ptr[-1] = real;
+
+ return faked_ptr;
+}
+
+void qFreeAligned(void *ptr)
+{
+ if (!ptr)
+ return;
+ void **ptr2 = static_cast<void **>(ptr);
+ free(ptr2[-1]);
+}
+
+QT_END_NAMESPACE
+