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root/usr/lib/libc/stdio/refill.c

DEFINITIONS

1. lflush
2. __srefill

   1 /*-
   2  * Copyright (c) 1990, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Chris Torek.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  33 #include <errno.h>
  34 #include <stdio.h>
  35 #include <stdlib.h>
  36 #include "local.h"
  38 static int
lflush(FILE *fp)
  40 {
  42         if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR))
  43                 return (__sflush(fp));
  44         return (0);
  45 }
  47 /*
  48  * Refill a stdio buffer.
  49  * Return EOF on eof or error, 0 otherwise.
  50  */
  51 int
__srefill(fp)
FILE *fp;
  54 {
  56         /* make sure stdio is set up */
  57         if (!__sdidinit)
__sinit();
fp->_r = 0;             /* largely a convenience for callers */
  62         /* SysV does not make this test; take it out for compatibility */
  63         if (fp->_flags & __SEOF)
  64                 return (EOF);
  66         /* if not already reading, have to be reading and writing */
  67         if ((fp->_flags & __SRD) == 0) {
  68                 if ((fp->_flags & __SRW) == 0) {
errno = EBADF;
  70                         return (EOF);
  71                 }
  72                 /* switch to reading */
  73                 if (fp->_flags & __SWR) {
  74                         if (__sflush(fp))
  75                                 return (EOF);
fp->_flags &= ~__SWR;
fp->_w = 0;
  78                 }
fp->_flags |= __SRD;
  80         } else {
  81                 /*
  82                  * We were reading.  If there is an ungetc buffer,
  83                  * we must have been reading from that.  Drop it,
  84                  * restoring the previous buffer (if any).  If there
  85                  * is anything in that buffer, return.
  86                  */
  87                 if (HASUB(fp)) {
FREEUB(fp);
  89                         if ((fp->_r = fp->_ur) != 0) {
fp->_p = fp->_up;
  91                                 return (0);
  92                         }
  93                 }
  94         }
  96         if (fp->_bf._base == NULL)
__smakebuf(fp);
  99         /*
 100          * Before reading from a line buffered or unbuffered file,
 101          * flush all line buffered output files, per the ANSI C
 102          * standard.
 103          */
 104         if (fp->_flags & (__SLBF|__SNBF))
 105                 (void) _fwalk(lflush);
fp->_p = fp->_bf._base;
fp->_r = __sread(fp, (char *)fp->_p, fp->_bf._size);
 108         if (fp->_r <= 0) {
 109                 if (fp->_r == 0)
fp->_flags |= __SEOF;
 111                 else {
fp->_r = 0;
fp->_flags |= __SERR;
 114                 }
 115                 return (EOF);
 116         }
 117         return (0);
 118 }