glibc/benchtests/bench-strncpy.c

/* Measure strncpy functions.
   Copyright (C) 2013-2015 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#ifndef STRNCPY_RESULT
# define STRNCPY_RESULT(dst, len, n) dst
# define TEST_MAIN
# define TEST_NAME "strncpy"
# include "bench-string.h"

char *simple_strncpy (char *, const char *, size_t);
char *stupid_strncpy (char *, const char *, size_t);

IMPL (stupid_strncpy, 0)
IMPL (simple_strncpy, 0)
IMPL (strncpy, 1)

char *
simple_strncpy (char *dst, const char *src, size_t n)
{
  char *ret = dst;
  while (n--)
    if ((*dst++ = *src++) == '\0')
      {
	while (n--)
	  *dst++ = '\0';
	return ret;
      }
  return ret;
}

char *
stupid_strncpy (char *dst, const char *src, size_t n)
{
  size_t nc = strnlen (src, n);
  size_t i;

  for (i = 0; i < nc; ++i)
    dst[i] = src[i];
  for (; i < n; ++i)
    dst[i] = '\0';
  return dst;
}
#endif

typedef char *(*proto_t) (char *, const char *, size_t);

static void
do_one_test (impl_t *impl, char *dst, const char *src, size_t len, size_t n)
{
  size_t i, iters = INNER_LOOP_ITERS;
  timing_t start, stop, cur;

  if (CALL (impl, dst, src, n) != STRNCPY_RESULT (dst, len, n))
    {
      error (0, 0, "Wrong result in function %s %p %p", impl->name,
	     CALL (impl, dst, src, n), dst);
      ret = 1;
      return;
    }

  if (memcmp (dst, src, len > n ? n : len) != 0)
    {
      error (0, 0, "Wrong result in function %s", impl->name);
      ret = 1;
      return;
    }

  if (n > len)
    {
      size_t i;

      for (i = len; i < n; ++i)
	if (dst [i] != '\0')
	  {
	    error (0, 0, "Wrong result in function %s", impl->name);
	    ret = 1;
	    return;
	  }
    }

  TIMING_NOW (start);
  for (i = 0; i < iters; ++i)
    {
      CALL (impl, dst, src, n);
    }
  TIMING_NOW (stop);

  TIMING_DIFF (cur, start, stop);

  TIMING_PRINT_MEAN ((double) cur, (double) iters);
}

static void
do_test (size_t align1, size_t align2, size_t len, size_t n, int max_char)
{
  size_t i;
  char *s1, *s2;

  align1 &= 7;
  if (align1 + len >= page_size)
    return;

  align2 &= 7;
  if (align2 + len >= page_size)
    return;

  s1 = (char *) (buf1 + align1);
  s2 = (char *) (buf2 + align2);

  for (i = 0; i < len; ++i)
    s1[i] = 32 + 23 * i % (max_char - 32);
  s1[len] = 0;
  for (i = len + 1; i + align1 < page_size && i < len + 64; ++i)
    s1[i] = 32 + 32 * i % (max_char - 32);

  printf ("Length %4zd, n %4zd, alignment %2zd/%2zd:", len, n, align1, align2);

  FOR_EACH_IMPL (impl, 0)
    do_one_test (impl, s2, s1, len, n);

  putchar ('\n');
}

int
test_main (void)
{
  size_t i;

  test_init ();

  printf ("%28s", "");
  FOR_EACH_IMPL (impl, 0)
    printf ("\t%s", impl->name);
  putchar ('\n');

  for (i = 1; i < 8; ++i)
    {
      do_test (i, i, 16, 16, 127);
      do_test (i, i, 16, 16, 255);
      do_test (i, 2 * i, 16, 16, 127);
      do_test (2 * i, i, 16, 16, 255);
      do_test (8 - i, 2 * i, 1 << i, 2 << i, 127);
      do_test (2 * i, 8 - i, 2 << i, 1 << i, 127);
      do_test (8 - i, 2 * i, 1 << i, 2 << i, 255);
      do_test (2 * i, 8 - i, 2 << i, 1 << i, 255);
    }

  for (i = 1; i < 8; ++i)
    {
      do_test (0, 0, 4 << i, 8 << i, 127);
      do_test (0, 0, 16 << i, 8 << i, 127);
      do_test (8 - i, 2 * i, 4 << i, 8 << i, 127);
      do_test (8 - i, 2 * i, 16 << i, 8 << i, 127);
    }

  return ret;
}

#include "../test-skeleton.c"