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/*-
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 * Copyright (c) 1990, 1993
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 *        The Regents of the University of California.  All rights reserved.
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 *
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 * This code is derived from software contributed to Berkeley by
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 * Chris Torek.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 * 3. Neither the name of the University nor the names of its contributors
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 *    may be used to endorse or promote products derived from this software
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 *    without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 * SUCH DAMAGE.
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 */
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#include <stdio.h>
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#include <string.h>
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#include "local.h"
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#include "fvwrite.h"
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/*
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 * Write some memory regions.  Return zero on success, EOF on error.
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 *
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 * This routine is large and unsightly, but most of the ugliness due
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 * to the three different kinds of output buffering is handled here.
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 */
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int
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__sfvwrite(fp, uio)
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        FILE *fp;
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        struct __suio *uio;
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{
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        size_t len;
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        char *p;
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        struct __siov *iov;
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        int w, s;
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        char *nl;
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        int nlknown, nldist;
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        if ((len = uio->uio_resid) == 0)
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                return (0);
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        /* make sure we can write */
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        if (cantwrite(fp))
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                return (EOF);
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#define        MIN(a, b) ((a) < (b) ? (a) : (b))
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#define        COPY(n)          (void)memcpy((void *)fp->_p, (void *)p, (size_t)(n))
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        iov = uio->uio_iov;
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        p = iov->iov_base;
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        len = iov->iov_len;
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        iov++;
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#define GETIOV(extra_work) \
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        while (len == 0) { \
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                extra_work; \
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                p = iov->iov_base; \
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                len = iov->iov_len; \
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                iov++; \
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        }
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        if (fp->_flags & __SNBF) {
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                /*
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                 * Unbuffered: write up to BUFSIZ bytes at a time.
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                 */
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                do {
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                        GETIOV(;);
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                        w = __swrite(fp, p, MIN(len, BUFSIZ));
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                        if (w <= 0)
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                                goto err;
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                        p += w;
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                        len -= w;
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                } while ((uio->uio_resid -= w) != 0);
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        } else if ((fp->_flags & __SLBF) == 0) {
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                /*
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                 * Fully buffered: fill partially full buffer, if any,
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                 * and then flush.  If there is no partial buffer, write
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                 * one _bf._size byte chunk directly (without copying).
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                 *
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                 * String output is a special case: write as many bytes
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                 * as fit, but pretend we wrote everything.  This makes
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                 * snprintf() return the number of bytes needed, rather
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                 * than the number used, and avoids its write function
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                 * (so that the write function can be invalid).
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                 */
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                do {
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                        GETIOV(;);
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                        w = fp->_w;
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                        if (fp->_flags & __SSTR) {
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                                if (len < w)
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                                        w = len;
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                                COPY(w);        /* copy MIN(fp->_w,len), */
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                                fp->_w -= w;
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                                fp->_p += w;
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                                w = len;        /* but pretend copied all */
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                        } else if (fp->_p > fp->_bf._base && len > w) {
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                                /* fill and flush */
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                                COPY(w);
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                                /* fp->_w -= w; */ /* unneeded */
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                                fp->_p += w;
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                                if (fflush(fp))
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                                        goto err;
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                        } else if (len >= (w = fp->_bf._size)) {
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                                /* write directly */
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                                w = __swrite(fp, p, w);
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                                if (w <= 0)
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                                        goto err;
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                        } else {
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                                /* fill and done */
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                                w = len;
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                                COPY(w);
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                                fp->_w -= w;
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                                fp->_p += w;
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                        }
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                        p += w;
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                        len -= w;
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                } while ((uio->uio_resid -= w) != 0);
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        } else {
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                /*
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                 * Line buffered: like fully buffered, but we
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                 * must check for newlines.  Compute the distance
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                 * to the first newline (including the newline),
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                 * or `infinity' if there is none, then pretend
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                 * that the amount to write is MIN(len,nldist).
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                 */
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                nlknown = 0;
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                nldist = 0;        /* XXX just to keep gcc happy */
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                do {
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                        GETIOV(nlknown = 0);
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                        if (!nlknown) {
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                                nl = memchr((void *)p, '\n', len);
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                                nldist = nl ? nl + 1 - p : len + 1;
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                                nlknown = 1;
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                        }
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                        s = MIN(len, nldist);
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                        w = fp->_w + fp->_bf._size;
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                        if (fp->_p > fp->_bf._base && s > w) {
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                                COPY(w);
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                                /* fp->_w -= w; */
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                                fp->_p += w;
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                                if (fflush(fp))
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                                        goto err;
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                        } else if (s >= (w = fp->_bf._size)) {
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                                w = __swrite(fp, p, w);
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                                if (w <= 0)
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                                         goto err;
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                        } else {
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                                w = s;
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                                COPY(w);
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                                fp->_w -= w;
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                                fp->_p += w;
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                        }
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                        if ((nldist -= w) == 0) {
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                                /* copied the newline: flush and forget */
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                                if (fflush(fp))
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                                        goto err;
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                                nlknown = 0;
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                        }
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                        p += w;
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                        len -= w;
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                } while ((uio->uio_resid -= w) != 0);
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        }
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        return (0);
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err:
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        fp->_flags |= __SERR;
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        return (EOF);
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}