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/*

FUNCTION

        <<memmove>>---move possibly overlapping memory

INDEX

        memmove

ANSI_SYNOPSIS

        #include <string.h>

        void *memmove(void *<[dst]>, const void *<[src]>, size_t <[length]>);

TRAD_SYNOPSIS

        #include <string.h>

        void *memmove(<[dst]>, <[src]>, <[length]>)

        void *<[dst]>;

        void *<[src]>;

        size_t <[length]>;

DESCRIPTION

        This function moves <[length]> characters from the block of

        memory starting at <<*<[src]>>> to the memory starting at

        <<*<[dst]>>>. <<memmove>> reproduces the characters correctly

        at <<*<[dst]>>> even if the two areas overlap.

RETURNS

        The function returns <[dst]> as passed.

PORTABILITY

<<memmove>> is ANSI C.

<<memmove>> requires no supporting OS subroutines.

QUICKREF

        memmove ansi pure

*/

#include <string.h>

/*SUPPRESS 20*/

_PTR

_DEFUN (memmove, (dst_void, src_void, length),

        _PTR dst_void _AND

        _CONST _PTR src_void _AND

        size_t length)

{

  char *dst = dst_void;

  _CONST char *src = src_void;

  if (src < dst && dst < src + length)

    {

      /* Have to copy backwards */

      src += length;

      dst += length;

      while (length--)

        {

          *--dst = *--src;

        }

    }

  else

    {

      while (length--)

        {

          *dst++ = *src++;

        }

    }

  return dst_void;

}