1: /* Copy memory to memory until the specified number of bytes
    2:    has been copied with error checking.  Overlap is NOT handled correctly.
    3:    Copyright (C) 1991, 1997, 2003, 2004 Free Software Foundation, Inc.
    4:    This file is part of the GNU C Library.
    5:    Contributed by Torbjorn Granlund (tege@sics.se).
    6: 
    7:    The GNU C Library is free software; you can redistribute it and/or
    8:    modify it under the terms of the GNU Lesser General Public
    9:    License as published by the Free Software Foundation; either
   10:    version 2.1 of the License, or (at your option) any later version.
   11: 
   12:    The GNU C Library is distributed in the hope that it will be useful,
   13:    but WITHOUT ANY WARRANTY; without even the implied warranty of
   14:    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   15:    Lesser General Public License for more details.
   16: 
   17:    You should have received a copy of the GNU Lesser General Public
   18:    License along with the GNU C Library; if not, write to the Free
   19:    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   20:    02111-1307 USA.  */
   21: 
   22: #include <string.h>
   23: #include <memcopy.h>
   24: #include <pagecopy.h>
   25: 
   26: void *
   27: __memcpy_chk (dstpp, srcpp, len, dstlen)
   28:      void *dstpp;
   29:      const void *srcpp;
   30:      size_t len;
   31:      size_t dstlen;
   32: {
   33:   if (__builtin_expect (dstlen < len, 0))
   34:     __chk_fail ();
   35: 
   36:   unsigned long int dstp = (long int) dstpp;
   37:   unsigned long int srcp = (long int) srcpp;
   38: 
   39:   /* Copy from the beginning to the end.  */
   40: 
   41:   /* If there not too few bytes to copy, use word copy.  */
   42:   if (len >= OP_T_THRES)
   43:     {
   44:       /* Copy just a few bytes to make DSTP aligned.  */
   45:       len -= (-dstp) % OPSIZ;
   46:       BYTE_COPY_FWD (dstp, srcp, (-dstp) % OPSIZ);
   47: 
   48:       /* Copy whole pages from SRCP to DSTP by virtual address manipulation,
   49:          as much as possible.  */
   50: 
   51:       PAGE_COPY_FWD_MAYBE (dstp, srcp, len, len);
   52: 
   53:       /* Copy from SRCP to DSTP taking advantage of the known alignment of
   54:          DSTP.  Number of bytes remaining is put in the third argument,
   55:          i.e. in LEN.  This number may vary from machine to machine.  */
   56: 
   57:       WORD_COPY_FWD (dstp, srcp, len, len);
   58: 
   59:       /* Fall out and copy the tail.  */
   60:     }
   61: 
   62:   /* There are just a few bytes to copy.  Use byte memory operations.  */
   63:   BYTE_COPY_FWD (dstp, srcp, len);
   64: 
   65:   return dstpp;
   66: }