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#include <string>
#include <list>
#include <utility>

#define PTR


// This is purposefully badly packed
struct ExpensiveType
{
    int heapDataSize;
    bool trueOrFalse1;
    double loadsOfData[1024];
    char* heapData;
    bool trueOrFalse2;
    std::string iHaveACtor;
    std::list<std::string> expensive;
};

// The way I would classically do it - I don't use non-const refs in
// functions like this since I often forget that they can modify the
// object if I don't look explicitly at the function signature
void DoSomething(ExpensiveType* inOut)
{
    std::swap(inOut->trueOrFalse1, inOut->trueOrFalse2);
    for (auto& i : inOut->loadsOfData)
        i /= 2.0;

    inOut->iHaveACtor += "  argh this should probably require the string to allocate more memory";

    if (inOut->heapData != nullptr)
    {
        char* temp = new char[inOut->heapDataSize];
        std::copy(inOut->heapData, inOut->heapData+inOut->heapDataSize, temp);
        delete [] inOut->heapData;
        inOut->heapData = temp;
    }

    auto tempFront = inOut->expensive.front();
    auto tempBack = inOut->expensive.back();
    inOut->expensive.pop_front();
    inOut->expensive.pop_back();
    inOut->expensive.push_front(tempBack);
    inOut->expensive.push_back(tempFront);
}

// Using pass-by-value
ExpensiveType DoSomethingElse(ExpensiveType in)
{
    std::swap(in.trueOrFalse1, in.trueOrFalse2);
    for (auto& i : in.loadsOfData)
        i /= 2.0;

    in.iHaveACtor += "  argh this should probably require the string to allocate more memory";

    if (in.heapData != nullptr)
    {
        char* temp = new char[in.heapDataSize];
        std::copy(in.heapData, in.heapData+in.heapDataSize, temp);
        delete [] in.heapData;
        in.heapData = temp;
    }

    auto tempFront = in.expensive.front();
    auto tempBack = in.expensive.back();
    in.expensive.pop_front();
    in.expensive.pop_back();
    in.expensive.push_front(tempBack);
    in.expensive.push_back(tempFront);

    return in;
}

int main(void)
{
    ExpensiveType data;
    data.trueOrFalse1 = true;
    data.trueOrFalse2 = false;
    for (int i = 0; i < 1024; ++i)
    {
        data.loadsOfData[i] = i;
        data.expensive.push_back(std::to_string(i));
    }
    data.heapDataSize = 10;
    data.heapData = new char[data.heapDataSize];
    for (int i = 0; i < data.heapDataSize; ++i)
        data.heapData[i] = data.heapDataSize - i;

    for (int i = 0; i < 10e3; ++i)
    {
#ifdef PTR
        DoSomething(&data);
#else
        data = DoSomethingElse(data);
#endif
        // try and make sure the loop doesn't get optimised out
        data.trueOrFalse1 = !data.trueOrFalse1;
    }

#ifdef PTR
        DoSomething(&data);
#else
        data = DoSomethingElse(data);
#endif

        return 0;
}


# Unoptimised Clang 3.7 (-O0)
## Value
$ for i in {1..10}; do time bin/test; done

real    0m1.259s
user    0m1.110s
sys 0m0.143s

real    0m1.260s
user    0m1.138s
sys 0m0.116s

real    0m1.251s
user    0m1.163s
sys 0m0.088s

real    0m1.252s
user    0m1.119s
sys 0m0.128s

real    0m1.258s
user    0m1.178s
sys 0m0.080s

real    0m1.260s
user    0m1.103s
sys 0m0.152s

real    0m1.254s
user    0m1.125s
sys 0m0.124s

real    0m1.254s
user    0m1.149s
sys 0m0.099s

real    0m1.254s
user    0m1.145s
sys 0m0.104s

real    0m1.258s
user    0m1.140s
sys 0m0.112s

## Pointer
$ for i in {1..10}; do time bin/test; done

real    0m0.033s
user    0m0.030s
sys 0m0.004s

real    0m0.033s
user    0m0.033s
sys 0m0.000s

real    0m0.033s
user    0m0.033s
sys 0m0.000s

real    0m0.033s
user    0m0.029s
sys 0m0.004s

real    0m0.033s
user    0m0.033s
sys 0m0.000s

real    0m0.034s
user    0m0.034s
sys 0m0.000s

real    0m0.033s
user    0m0.033s
sys 0m0.005s

real    0m0.033s
user    0m0.033s
sys 0m0.000s

real    0m0.033s
user    0m0.033s
sys 0m0.000s

real    0m0.035s
user    0m0.034s
sys 0m0.000s

# Clang optimised (-O2 -flto -march=native -mfpmath=sse)
# Value
$ for i in {1..10}; do time bin/test; done

real    0m0.801s
user    0m0.665s
sys 0m0.136s

real    0m0.800s
user    0m0.671s
sys 0m0.128s

real    0m0.796s
user    0m0.659s
sys 0m0.136s

real    0m0.795s
user    0m0.698s
sys 0m0.096s

real    0m0.792s
user    0m0.663s
sys 0m0.129s

real    0m0.792s
user    0m0.662s
sys 0m0.128s

real    0m0.800s
user    0m0.680s
sys 0m0.120s

real    0m0.797s
user    0m0.660s
sys 0m0.133s

real    0m0.805s
user    0m0.676s
sys 0m0.128s

real    0m0.794s
user    0m0.678s
sys 0m0.116s

## Pointer
$ for i in {1..10}; do time bin/test; done

real    0m0.005s
user    0m0.000s
sys 0m0.005s

real    0m0.005s
user    0m0.005s
sys 0m0.000s

real    0m0.005s
user    0m0.000s
sys 0m0.005s

real    0m0.005s
user    0m0.003s
sys 0m0.003s

real    0m0.005s
user    0m0.005s
sys 0m0.000s

real    0m0.006s
user    0m0.006s
sys 0m0.000s

real    0m0.005s
user    0m0.005s
sys 0m0.000s

real    0m0.005s
user    0m0.005s
sys 0m0.000s

real    0m0.005s
user    0m0.005s
sys 0m0.000s

real    0m0.005s
user    0m0.003s
sys 0m0.003s

# GCC 4.8 Optimised (same as switches as clang)
## Value
$ for i in {1..10}; do time bin/test; done
real    0m0.781s
user    0m0.673s
sys 0m0.104s

real    0m0.784s
user    0m0.669s
sys 0m0.111s

real    0m0.779s
user    0m0.638s
sys 0m0.140s

real    0m0.777s
user    0m0.684s
sys 0m0.092s

real    0m0.787s
user    0m0.657s
sys 0m0.128s

real    0m0.778s
user    0m0.651s
sys 0m0.124s

real    0m0.779s
user    0m0.670s
sys 0m0.108s

real    0m0.778s
user    0m0.642s
sys 0m0.136s

real    0m0.774s
user    0m0.677s
sys 0m0.096s

real    0m0.777s
user    0m0.680s
sys 0m0.096s

## Pointer
$ for i in {1..10}; do time bin/test; done

real    0m0.010s
user    0m0.010s
sys 0m0.000s

real    0m0.010s
user    0m0.010s
sys 0m0.000s

real    0m0.011s
user    0m0.011s
sys 0m0.000s

real    0m0.009s
user    0m0.006s
sys 0m0.003s

real    0m0.010s
user    0m0.009s
sys 0m0.000s

real    0m0.010s
user    0m0.010s
sys 0m0.000s

real    0m0.010s
user    0m0.010s
sys 0m0.000s

real    0m0.010s
user    0m0.009s
sys 0m0.000s

real    0m0.010s
user    0m0.009s
sys 0m0.000s

real    0m0.011s
user    0m0.010s
sys 0m0.000s