mempcpy.c

来自「linux下编程用 编译软件」· C语言 代码 · 共 69 行

/* Copyright (C) 2003  Free Software Foundation.

   Ensure builtin mempcpy performs correctly.

   Written by Kaveh Ghazi, 4/11/2003.  */

extern void abort (void);
typedef __SIZE_TYPE__ size_t;
extern size_t strlen(const char *);
extern void *memcpy (void *, const void *, size_t);
extern void *mempcpy (void *, const void *, size_t);
extern int memcmp (const void *, const void *, size_t);
extern int inside_main;

const char s1[] = "123";
char p[32] = "";
char *s2 = "defg";
char *s3 = "FGH";
size_t l1 = 1;

void
main_test (void)
{
  int i;

#if !defined __i386__ && !defined __x86_64__
  /* The functions below might not be optimized into direct stores on all
     arches.  It depends on how many instructions would be generated and
     what limits the architecture chooses in STORE_BY_PIECES_P.  */
  inside_main = 0;
#endif

  if (mempcpy (p, "ABCDE", 6) != p + 6 || memcmp (p, "ABCDE", 6))
    abort ();
  if (mempcpy (p + 16, "VWX" + 1, 2) != p + 16 + 2
      || memcmp (p + 16, "WX\0\0", 5))
    abort ();
  if (mempcpy (p + 1, "", 1) != p + 1 + 1 || memcmp (p, "A\0CDE", 6))
    abort ();
  if (mempcpy (p + 3, "FGHI", 4) != p + 3 + 4 || memcmp (p, "A\0CFGHI", 8))
    abort ();

  i = 8;
  memcpy (p + 20, "qrstu", 6);
  memcpy (p + 25, "QRSTU", 6);
  if (mempcpy (p + 25 + 1, s1, 3) != (p + 25 + 1 + 3)
      || memcmp (p + 25, "Q123U", 6))
    abort ();

  if (mempcpy (mempcpy (p, "abcdEFG", 4), "efg", 4) != p + 8
      || memcmp (p, "abcdefg", 8))
    abort();

  /* Test at least one instance of the __builtin_ style.  We do this
     to ensure that it works and that the prototype is correct.  */
  if (__builtin_mempcpy (p, "ABCDE", 6) != p + 6 || memcmp (p, "ABCDE", 6))
    abort ();

  /* If the result of mempcpy is ignored, gcc should use memcpy.
     This should be optimized always, so set inside_main again.  */
  inside_main = 1;
  mempcpy (p + 5, s3, 1);
  if (memcmp (p, "ABCDEFg", 8))
    abort ();
  mempcpy (p + 6, s1 + 1, l1);
  if (memcmp (p, "ABCDEF2", 8))
    abort ();
}