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scoutos / prex-0.9.0 / usr / lib / libc / stdio / refill.c @ 03e9c04a

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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 <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include "local.h"
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static int
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lflush(FILE *fp)
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{
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        if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR))
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                return (__sflush(fp));
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        return (0);
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}
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/*
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 * Refill a stdio buffer.
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 * Return EOF on eof or error, 0 otherwise.
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 */
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int
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__srefill(fp)
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        FILE *fp;
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{
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        /* make sure stdio is set up */
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        if (!__sdidinit)
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                __sinit();
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        fp->_r = 0;                /* largely a convenience for callers */
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        /* SysV does not make this test; take it out for compatibility */
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        if (fp->_flags & __SEOF)
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                return (EOF);
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        /* if not already reading, have to be reading and writing */
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        if ((fp->_flags & __SRD) == 0) {
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                if ((fp->_flags & __SRW) == 0) {
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                        errno = EBADF;
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                        return (EOF);
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                }
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                /* switch to reading */
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                if (fp->_flags & __SWR) {
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                        if (__sflush(fp))
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                                return (EOF);
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                        fp->_flags &= ~__SWR;
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                        fp->_w = 0;
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                }
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                fp->_flags |= __SRD;
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        } else {
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                /*
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                 * We were reading.  If there is an ungetc buffer,
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                 * we must have been reading from that.  Drop it,
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                 * restoring the previous buffer (if any).  If there
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                 * is anything in that buffer, return.
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                 */
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                if (HASUB(fp)) {
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                        FREEUB(fp);
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                        if ((fp->_r = fp->_ur) != 0) {
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                                fp->_p = fp->_up;
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                                return (0);
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                        }
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                }
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        }
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        if (fp->_bf._base == NULL)
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                __smakebuf(fp);
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        /*
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         * Before reading from a line buffered or unbuffered file,
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         * flush all line buffered output files, per the ANSI C
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         * standard.
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         */
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        if (fp->_flags & (__SLBF|__SNBF))
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                (void) _fwalk(lflush);
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        fp->_p = fp->_bf._base;
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        fp->_r = __sread(fp, (char *)fp->_p, fp->_bf._size);
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        if (fp->_r <= 0) {
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                if (fp->_r == 0)
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                        fp->_flags |= __SEOF;
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                else {
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                        fp->_r = 0;
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                        fp->_flags |= __SERR;
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                }
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                return (EOF);
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        }
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        return (0);
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}