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glibc  2.9
memcpy_chk.c File Reference
#include <string.h>
#include <memcopy.h>
#include <pagecopy.h>

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void * __memcpy_chk (void *dstpp, const void *srcpp, size_t len, size_t dstlen)

Function Documentation

void* __memcpy_chk ( void *  dstpp,
const void *  srcpp,
size_t  len,
size_t  dstlen 

Definition at line 27 of file memcpy_chk.c.

  if (__builtin_expect (dstlen < len, 0))
    __chk_fail ();

  unsigned long int dstp = (long int) dstpp;
  unsigned long int srcp = (long int) srcpp;

  /* Copy from the beginning to the end.  */

  /* If there not too few bytes to copy, use word copy.  */
  if (len >= OP_T_THRES)
      /* Copy just a few bytes to make DSTP aligned.  */
      len -= (-dstp) % OPSIZ;
      BYTE_COPY_FWD (dstp, srcp, (-dstp) % OPSIZ);

      /* Copy whole pages from SRCP to DSTP by virtual address manipulation,
        as much as possible.  */

      PAGE_COPY_FWD_MAYBE (dstp, srcp, len, len);

      /* Copy from SRCP to DSTP taking advantage of the known alignment of
        DSTP.  Number of bytes remaining is put in the third argument,
        i.e. in LEN.  This number may vary from machine to machine.  */

      WORD_COPY_FWD (dstp, srcp, len, len);

      /* Fall out and copy the tail.  */

  /* There are just a few bytes to copy.  Use byte memory operations.  */
  BYTE_COPY_FWD (dstp, srcp, len);

  return dstpp;

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