stdio/common/fwrite.c

	fwrite.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 1989 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*      Copyright (c) 1984 AT&T */
/*        All Rights Reserved   */

#pragma ident   "%Z%%M% %I% %E% SMI"  /* from S5R2 3.6 */

/*LINTLIBRARY*/
/*
 * This version writes directly to the buffer rather than looping on putc.
 * Ptr args aren't checked for NULL because the program would be a
 * catastrophic mess anyway.  Better to abort than just to return NULL.
 *
 * This version does buffered writes larger than BUFSIZ directly, when
 * the buffer is empty.
 */
#include <stdio.h>
#include "stdiom.h"

#define MIN(x, y)       (x < y ? x : y)

extern char *memcpy();

int
fwrite(ptr, size, count, iop)
char *ptr;
int size, count;
register FILE *iop;
{
    register unsigned nleft;
    register int n;
    register unsigned char *cptr, *bufend;
    register unsigned char *prev_ptr;

    if (size <= 0 || count <= 0 || _WRTCHK(iop))
            return (0);

    bufend = iop->_base + iop->_bufsiz;
    nleft = count*size;

    /* if the file is unbuffered, or if the iop->ptr = iop->base, and there
       is > BUFSZ chars to write, we can do a direct write */
    prev_ptr = iop->_ptr;
    if (iop->_base >= iop->_ptr)  { /*this covers the unbuffered case, too*/
        if (((iop->_flag & _IONBF) != 0) || (nleft >= BUFSIZ))  {
            if ((n=write(fileno(iop),ptr,nleft)) != nleft)
                {
                iop->_flag |= _IOERR;
                n = (n >= 0) ? n : 0;
            }
            return n/size;
        }
    }
    /* Put characters in the buffer */
    /* note that the meaning of n when just starting this loop is
       irrelevant.  It is defined in the loop */
    for (; ; ptr += n) {
            while ((n = bufend - (cptr = iop->_ptr)) <= 0)  /* full buf */
                    if (_xflsbuf(iop) == EOF)
                            return (count - (nleft + size - 1)/size);
            n = MIN(nleft, n);
            (void) memcpy((char *) cptr, ptr, n);
            iop->_cnt -= n;
            iop->_ptr += n;
            _BUFSYNC(iop);
        /* done; flush if linebuffered with a newline */
            if ((nleft -= n) == 0)  {
            if (iop->_flag & (_IOLBF | _IONBF)) {
                        if ((iop->_flag & _IONBF) || (memchr(prev_ptr,
                    '\n',iop->_ptr - prev_ptr) != NULL))  {
                        (void) _xflsbuf(iop);
                }
            }
                    return (count);
            }
    }
}