#include <string.h>
 
#include <iostream>
#include <chrono>
#include <iostream>
#include <iomanip>
 
using namespace std::chrono;
 
// based on
// http://w...content-available-to-author-only...t.org/doc/libs/1_54_0/libs/chrono/example/await_keystroke.cpp
template<class Clock>
class Timer
{
typename Clock::time_point start;
 
public:
Timer()
: start(Clock::now()) {
}
 
typename Clock::duration elapsed() const {
return (Clock::now() - start);
}
 
double seconds() const {
return (elapsed().count() *
((double)Clock::period::num / Clock::period::den));
}
};
 
#define BUFFERSIZE (100 * 1024 * 1024) // 100 mb
#define LOOPS 10
#define MAXSTRIDE 128
 
int main()
{
char *b1 = (char *)::malloc(BUFFERSIZE + MAXSTRIDE);
char *b2 = (char *)::malloc(BUFFERSIZE + MAXSTRIDE);
::memset(b1, 0, BUFFERSIZE + MAXSTRIDE);
 
// Each test is performed |LOOP| times; the average run-time is then printed.
 
// Test memmove() by inserting a small gap at the beginning of the buffer
for (int stride = 2; stride <= MAXSTRIDE; stride *= 2) {
Timer<high_resolution_clock> t;
for (int i = 0; i < LOOPS; i++)
memmove(b2, b1, BUFFERSIZE);
double seconds = t.seconds();
std::cout << "memmove (" << std::setfill('0') << std::setw(3)
<< stride << ") " << (seconds / LOOPS) << std::endl;
}
 
// Test memcpy() by copying from buffer b1 to b2
Timer<high_resolution_clock> t;
for (int i = 0; i < LOOPS; i++)
memcpy(b2, b1, BUFFERSIZE);
double seconds = t.seconds();
std::cout << "memcpy " << (seconds / LOOPS) << std::endl;
 
::free(b1);
::free(b2);
} 

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