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#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;

    }

    union { void *ptr; void **pptr; quintptr n; } real, faked;

    // 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.

    real.ptr = qRealloc(actualptr, newsize + alignment);

    if (!real.ptr)

        return 0;

    faked.n = real.n + alignment;

    faked.n &= ~(alignment - 1);

    // 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.pptr[-1] = real.ptr;

    return faked.ptr;

}

void qFreeAligned(void *ptr)

{

    if (!ptr)

        return;

    void **ptr2 = static_cast<void **>(ptr);

    free(ptr2[-1]);

}

QT_END_NAMESPACE