NetBSD/usr.sbin/sup/source/ffilecopy.c

122 lines
3.4 KiB
C

/* $NetBSD: ffilecopy.c,v 1.11 2009/10/18 15:23:54 christos Exp $ */
/*
* Copyright (c) 1991 Carnegie Mellon University
* All Rights Reserved.
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the rights
* to redistribute these changes.
*/
#include <stdio.h>
#include "supcdefs.h"
#include "supextern.h"
/*
* Define two macros for fast file copying
*
* FBUF_HACK: this will copy data directly between the
* underlying OSs FILE buffers
*
* FFLAG_HACK: this will set necessary OS FILE flags
* after we've hacked the buffers up
*/
#if defined(__SEOF)
# define FBUF_HACK(here,there) \
do { \
if ((here)->_r > 0) { \
i = write(therefile, (here)->_p, (size_t)(here)->_r); \
if (i != (here)->_r) \
return EOF; \
(here)->_p = (here)->_bf._base; \
(here)->_r = 0; \
} \
} while (/*CONSTCOND*/0)
# define FFLAG_HACK(file) (file)->_flags |= __SEOF
#elif defined(_IOEOF)
# define FBUF_HACK(here, there) \
do { \
if ((here)->_cnt > 0) { \
i = write(therefile, (here)->_ptr, (here)->_cnt ); \
if (i != (here)->_cnt) \
return EOF; \
(here)->_ptr = (here)->_base; \
(here)->_cnt = 0; \
} \
} while (/*CONSTCOND*/0)
# define FFLAG_HACK(file) (file)->_flag |= _IOEOF;
#else
# define FBUF_HACK(here, there) /* Nada */
# define FFLAG_HACK(here) (void)fseeko(here, (off_t)0, SEEK_END);
#endif
/* ffilecopy -- very fast buffered file copy
*
* Usage: i = ffilecopy (here,there)
* int i;
* FILE *here, *there;
*
* Ffilecopy is a very fast routine to copy the rest of a buffered
* input file to a buffered output file. Here and there are open
* buffers for reading and writing (respectively); ffilecopy
* performs a file-copy faster than you should expect to do it
* yourself. Ffilecopy returns 0 if everything was OK; EOF if
* there was any error. Normally, the input file will be left in
* EOF state (feof(here) will return TRUE), and the output file will be
* flushed (i.e. all data on the file rather in the core buffer).
* It is not necessary to flush the output file before ffilecopy.
*
* HISTORY
* 20-Nov-79 Steven Shafer (sas) at Carnegie-Mellon University
* Created for VAX.
*
*/
ssize_t
ffilecopy(FILE * here, FILE * there)
{
int i, herefile, therefile;
herefile = fileno(here);
therefile = fileno(there);
if (fflush(there) == EOF) /* flush pending output */
return EOF;
/* if we know any buffer tricks, do them now */
FBUF_HACK(here,there);
/* copy the rest of the file directly (avoiding FILE buffers) */
i = filecopy(herefile, therefile); /* fast file copy */
if (i < 0)
return EOF;
/* ensure we are at the end of the file */
FFLAG_HACK(here);
return 0;
}