mmap-shuffle.c

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/** Creates a 128 kB file and repeatedly shuffles data in it
   through a memory mapping. */
 
#include <stdio.h>
#include <string.h>
#include <syscall.h>
#include "tests/arc4.h"
#include "tests/cksum.h"
#include "tests/lib.h"
#include "tests/main.h"
 
#define SIZE (128 * 1024)
 
static char *buf = (char *) 0x10000000;
 
void
test_main (void)
{
  size_t i;
  int handle;
 
  /* Create file, mmap. */
  CHECK (create ("buffer", SIZE), "create \"buffer\"");
  CHECK ((handle = open ("buffer")) > 1, "open \"buffer\"");
  CHECK (mmap (handle, buf) != MAP_FAILED, "mmap \"buffer\"");
 
  /* Initialize. */
  for (i = 0; i < SIZE; i++)
    buf[i] = i * 257;
  msg ("init: cksum=%lu", cksum (buf, SIZE));
    
  /* Shuffle repeatedly. */
  for (i = 0; i < 10; i++)
    {
      shuffle (buf, SIZE, 1);
      msg ("shuffle %zu: cksum=%lu", i, cksum (buf, SIZE));
    }
}