/***********************************************************************

*                                                                      *

*               This software is part of the ast package               *

*          Copyright (c) 1985-2011 AT&T Intellectual Property          *

*                      and is licensed under the                       *

*                 Eclipse Public License, Version 1.0                  *

*                    by AT&T Intellectual Property                     *

*                                                                      *

*                A copy of the License is available at                 *

*          http://www.eclipse.org/org/documents/epl-v10.html           *

*         (with md5 checksum b35adb5213ca9657e911e9befb180842)         *

*                                                                      *

*              Information and Software Systems Research               *

*                            AT&T Research                             *

*                           Florham Park NJ                            *

*                                                                      *

*                 Glenn Fowler <gsf@research.att.com>                  *

*                  David Korn <dgk@research.att.com>                   *

*                   Phong Vo <kpv@research.att.com>                    *

*                                                                      *

***********************************************************************/

#pragma prototyped

/*

 * Glenn Fowler

 * AT&T Bell Laboratories

 *

 * copy from rfd to wfd (with conditional mmap hacks)

 */

#include <ast.h>

#include <ast_mmap.h>

#if _mmap_worthy > 1

#include <ls.h>

#define MAPSIZE		(1024*256)

#endif

#undef	BUFSIZ

#define BUFSIZ		4096

/*

 * copy n bytes from rfd to wfd

 * actual byte count returned

 * if n<=0 then ``good'' size is used

 */

off_t

astcopy(int rfd, int wfd, off_t n)

{

	register off_t	c;

#ifdef MAPSIZE

	off_t		pos;

	off_t		mapsize;

	char*		mapbuf;

	struct stat	st;

#endif

	static int	bufsiz;

	static char*	buf;

	if (n <= 0 || n >= BUFSIZ * 2)

	{

#if MAPSIZE

		if (!fstat(rfd, &st) && S_ISREG(st.st_mode) && (pos = lseek(rfd, (off_t)0, 1)) != ((off_t)-1))

		{

			if (pos >= st.st_size) return(0);

			mapsize = st.st_size - pos;

			if (mapsize > MAPSIZE) mapsize = (mapsize > n && n > 0) ? n : MAPSIZE;

			if (mapsize >= BUFSIZ * 2 && (mapbuf = (char*)mmap(NiL, mapsize, PROT_READ, MAP_SHARED, rfd, pos)) != ((caddr_t)-1))

			{

				if (write(wfd, mapbuf, mapsize) != mapsize || lseek(rfd, mapsize, 1) == ((off_t)-1)) return(-1);

				munmap((caddr_t)mapbuf, mapsize);

				return(mapsize);

			}

		}

#endif

		if (n <= 0) n = BUFSIZ;

	}

	if (n > bufsiz)

	{

		if (buf) free(buf);

		bufsiz = roundof(n, BUFSIZ);

		if (!(buf = newof(0, char, bufsiz, 0))) return(-1);

	}

	if ((c = read(rfd, buf, (size_t)n)) > 0 && write(wfd, buf, (size_t)c) != c) c = -1;

	return(c);

}