allocators.h

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#ifndef NPSTAT_ALLOCATORS_HH_
#define NPSTAT_ALLOCATORS_HH_

#include <cassert>

namespace npstat {
    template <typename T>
    inline T* makeBuffer(unsigned sizeNeeded, T* stackBuffer,
                         unsigned sizeofStackBuffer)
    {
        if (sizeNeeded > sizeofStackBuffer || stackBuffer == nullptr)
            return new T[sizeNeeded];
        else
            return stackBuffer;
    }

    template <typename T>
    inline void destroyBuffer(T* thisBuffer, const T* stackBuffer)
    {
        if (thisBuffer != stackBuffer)
            delete [] thisBuffer;
    }

    template <typename T1, typename T2>
    inline void copyBuffer(T1* dest, const T2* source, const unsigned long len)
    {
        if (len)
        {
            assert(dest);
            assert(source);
            for (unsigned long i=0; i<len; ++i)
                *dest++ = static_cast<T1>(*source++);
        }
    }

    template <typename T1, typename T2>
    inline void transposeBuffer(T1* dest, const T2* source,
                                const unsigned long dim)
    {
        if (dim)
        {
            assert(dest);
            assert(source);
            for (unsigned long i=0; i<dim; ++i)
            {
                for (unsigned long j=0; j<dim; ++j)
                    dest[j*dim] = static_cast<T1>(*source++);
                ++dest;
            }
        }
    }

    template <typename T1, typename T2>
    inline void transposeBuffer(T1* dest, const T2* source,
                                const unsigned long M,
                                const unsigned long N)
    {
        if (M && N)
        {
            assert(dest);
            assert(source);
            for (unsigned long i=0; i<M; ++i)
            {
                for (unsigned long j=0; j<N; ++j)
                    dest[j*M] = static_cast<T1>(*source++);
                ++dest;
            }
        }
    }

    template <typename T>
    inline void clearBuffer(T* buf, const unsigned long len)
    {
        if (len)
        {
            assert(buf);
            const T zero = T();
            for (unsigned long i=0; i<len; ++i)
                *buf++ = zero;
        }
    }
}

#endif // NPSTAT_ALLOCATORS_HH_