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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. All advertising materials mentioning features or use of this software
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 *    must display the following acknowledgement:
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 *      This product includes software developed by the University of
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 *      California, Berkeley and its contributors.
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 * 4. 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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#if defined(LIBC_SCCS) && !defined(lint)
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#if 0
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static char sccsid[] = "@(#)fgets.c     8.2 (Berkeley) 12/22/93";
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#endif
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static const char rcsid[] =
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                "$\Id: fgets.c,v 1.5 1996/06/22 10:33:10 jraynard Exp $";
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#endif /* LIBC_SCCS and not lint */
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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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#ifdef _THREAD_SAFE
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#include <pthread.h>
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#include "pthread_private.h"
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#endif
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/*
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 * Read at most n-1 characters from the given file.
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 * Stop when a newline has been read, or the count runs out.
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 * Return first argument, or NULL if no characters were read.
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 */
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char *
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fgets(buf, n, fp)
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        char *buf;
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        register int n;
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        register FILE *fp;
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{
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        register size_t len;
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        register char *s;
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        register unsigned char *p, *t;
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        if (n <= 0)             /* sanity check */
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                return (NULL);
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#ifdef _THREAD_SAFE
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        _thread_flockfile(fp,__FILE__,__LINE__);
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#endif
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        s = buf;
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        n--;                    /* leave space for NUL */
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        while (n != 0) {
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                /*
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                 * If the buffer is empty, refill it.
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                 */
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                if ((len = fp->_r) <= 0) {
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                        if (__srefill(fp)) {
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                                /* EOF/error: stop with partial or no line */
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                                if (s == buf) {
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#ifdef _THREAD_SAFE
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                                        _thread_funlockfile(fp);
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#endif
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                                        return (NULL);
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                                }
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                                break;
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                        }
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                        len = fp->_r;
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                }
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                p = fp->_p;
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                /*
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                 * Scan through at most n bytes of the current buffer,
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                 * looking for '\n'.  If found, copy up to and including
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                 * newline, and stop.  Otherwise, copy entire chunk
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                 * and loop.
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                 */
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                if (len > n)
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                        len = n;
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                t = memchr((void *)p, '\n', len);
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                if (t != NULL) {
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                        len = ++t - p;
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                        fp->_r -= len;
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                        fp->_p = t;
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                        (void)memcpy((void *)s, (void *)p, len);
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                        s[len] = 0;
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#ifdef _THREAD_SAFE
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                        _thread_funlockfile(fp);
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#endif
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                        return (buf);
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                }
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                fp->_r -= len;
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                fp->_p += len;
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                (void)memcpy((void *)s, (void *)p, len);
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                s += len;
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                n -= len;
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        }
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        *s = 0;
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#ifdef _THREAD_SAFE
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        _thread_funlockfile(fp);
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#endif
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        return (buf);
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}