__memccpy.c

一个C源代码分析器

/* Copyright (C) 1991, 1992 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB.  If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA.  */

#include <ansidecl.h>
#include <string.h>


/* Copy no more than N bytes of SRC to DEST, stopping when C is found.
   Return the position in DEST one byte past where C was copied,
   or NULL if C was not found in the first N bytes of SRC.  */
PTR
DEFUN(__memccpy, (dest, src, c, n),
      PTR dest AND CONST PTR src AND int c AND size_t nbytes)
{
  /* Except when N > 65535, this is what a hand-coded version would
     do anyway.  */

  PTR found = memchr (src, c, n);

  if (found == NULL)
    {
      (void) memcpy (dest, src, n);
      return NULL;
    }

  (void) memcpy (dest, src, (char *) found + 1 - (char *) src);
  return (PTR) ((char *) dest + ((char *) found + 1 - (char *) src));
}