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/*-
 * Copyright (c) 1990, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)fvwrite.c   8.1 (Berkeley) 6/4/93";
#endif
static const char rcsid[] =
                "$\Id: fvwrite.c,v 1.3 1996/06/22 10:33:27 jraynard Exp $";
#endif /* LIBC_SCCS and not lint */

#include <stdio.h>
#include <string.h>
#include "local.h"
#include "fvwrite.h"

/*
 * Write some memory regions.  Return zero on success, EOF on error.
 *
 * This routine is large and unsightly, but most of the ugliness due
 * to the three different kinds of output buffering is handled here.
 */
int
__sfvwrite(fp, uio)
        register FILE *fp;
        register struct __suio *uio;
{
        register size_t len;
        register char *p;
        register struct __siov *iov;
        register int w, s;
        char *nl;
        int nlknown, nldist;

        if ((len = uio->uio_resid) == 0)
                return (0);
        /* make sure we can write */
        if (cantwrite(fp))
                return (EOF);

#define MIN(a, b) ((a) < (b) ? (a) : (b))
#define COPY(n)   (void)memcpy((void *)fp->_p, (void *)p, (size_t)(n))

        iov = uio->uio_iov;
        p = iov->iov_base;
        len = iov->iov_len;
        iov++;
#define GETIOV(extra_work) \
        while (len == 0) { \
                extra_work; \
                p = iov->iov_base; \
                len = iov->iov_len; \
                iov++; \
        }
        if (fp->_flags & __SNBF) {
                /*
                 * Unbuffered: write up to BUFSIZ bytes at a time.
                 */
                do {
                        GETIOV(;);
                        w = (*fp->_write)(fp->_cookie, p, MIN(len, BUFSIZ));
                        if (w <= 0)
                                goto err;
                        p += w;
                        len -= w;
                } while ((uio->uio_resid -= w) != 0);
        } else if ((fp->_flags & __SLBF) == 0) {
                /*
                 * Fully buffered: fill partially full buffer, if any,
                 * and then flush.  If there is no partial buffer, write
                 * one _bf._size byte chunk directly (without copying).
                 *
                 * String output is a special case: write as many bytes
                 * as fit, but pretend we wrote everything.  This makes
                 * snprintf() return the number of bytes needed, rather
                 * than the number used, and avoids its write function
                 * (so that the write function can be invalid).
                 */
                do {
                        GETIOV(;);
                        w = fp->_w;
                        if (fp->_flags & __SSTR) {
                                if (len < w)
                                        w = len;
                                COPY(w);        /* copy MIN(fp->_w,len), */
                                fp->_w -= w;
                                fp->_p += w;
                                w = len;        /* but pretend copied all */
                        } else if (fp->_p > fp->_bf._base && len > w) {
                                /* fill and flush */
                                COPY(w);
                                /* fp->_w -= w; */ /* unneeded */
                                fp->_p += w;
                                if (fflush(fp))
                                        goto err;
                        } else if (len >= (w = fp->_bf._size)) {
                                /* write directly */
                                w = (*fp->_write)(fp->_cookie, p, w);
                                if (w <= 0)
                                        goto err;
                        } else {
                                /* fill and done */
                                w = len;
                                COPY(w);
                                fp->_w -= w;
                                fp->_p += w;
                        }
                        p += w;
                        len -= w;
                } while ((uio->uio_resid -= w) != 0);
        } else {
                /*
                 * Line buffered: like fully buffered, but we
                 * must check for newlines.  Compute the distance
                 * to the first newline (including the newline),
                 * or `infinity' if there is none, then pretend
                 * that the amount to write is MIN(len,nldist).
                 */
                nlknown = 0;
                nldist = 0;     /* XXX just to keep gcc happy */
                do {
                        GETIOV(nlknown = 0);
                        if (!nlknown) {
                                nl = memchr((void *)p, '\n', len);
                                nldist = nl ? nl + 1 - p : len + 1;
                                nlknown = 1;
                        }
                        s = MIN(len, nldist);
                        w = fp->_w + fp->_bf._size;
                        if (fp->_p > fp->_bf._base && s > w) {
                                COPY(w);
                                /* fp->_w -= w; */
                                fp->_p += w;
                                if (fflush(fp))
                                        goto err;
                        } else if (s >= (w = fp->_bf._size)) {
                                w = (*fp->_write)(fp->_cookie, p, w);
                                if (w <= 0)
                                        goto err;
                        } else {
                                w = s;
                                COPY(w);
                                fp->_w -= w;
                                fp->_p += w;
                        }
                        if ((nldist -= w) == 0) {
                                /* copied the newline: flush and forget */
                                if (fflush(fp))
                                        goto err;
                                nlknown = 0;
                        }
                        p += w;
                        len -= w;
                } while ((uio->uio_resid -= w) != 0);
        }
        return (0);

err:
        fp->_flags |= __SERR;
        return (EOF);
}