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Annotation of prex-old/usr/lib/libc/stdio/refill.c, Revision 1.1.1.1

1.1       nbrk        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:  */
                     32:
                     33: #include <errno.h>
                     34: #include <stdio.h>
                     35: #include <stdlib.h>
                     36: #include "local.h"
                     37:
                     38: static int
                     39: lflush(FILE *fp)
                     40: {
                     41:
                     42:        if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR))
                     43:                return (__sflush(fp));
                     44:        return (0);
                     45: }
                     46:
                     47: /*
                     48:  * Refill a stdio buffer.
                     49:  * Return EOF on eof or error, 0 otherwise.
                     50:  */
                     51: int
                     52: __srefill(fp)
                     53:        FILE *fp;
                     54: {
                     55:
                     56:        /* make sure stdio is set up */
                     57:        if (!__sdidinit)
                     58:                __sinit();
                     59:
                     60:        fp->_r = 0;             /* largely a convenience for callers */
                     61:
                     62:        /* SysV does not make this test; take it out for compatibility */
                     63:        if (fp->_flags & __SEOF)
                     64:                return (EOF);
                     65:
                     66:        /* if not already reading, have to be reading and writing */
                     67:        if ((fp->_flags & __SRD) == 0) {
                     68:                if ((fp->_flags & __SRW) == 0) {
                     69:                        errno = EBADF;
                     70:                        return (EOF);
                     71:                }
                     72:                /* switch to reading */
                     73:                if (fp->_flags & __SWR) {
                     74:                        if (__sflush(fp))
                     75:                                return (EOF);
                     76:                        fp->_flags &= ~__SWR;
                     77:                        fp->_w = 0;
                     78:                }
                     79:                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)) {
                     88:                        FREEUB(fp);
                     89:                        if ((fp->_r = fp->_ur) != 0) {
                     90:                                fp->_p = fp->_up;
                     91:                                return (0);
                     92:                        }
                     93:                }
                     94:        }
                     95:
                     96:        if (fp->_bf._base == NULL)
                     97:                __smakebuf(fp);
                     98:
                     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);
                    106:        fp->_p = fp->_bf._base;
                    107:        fp->_r = __sread(fp, (char *)fp->_p, fp->_bf._size);
                    108:        if (fp->_r <= 0) {
                    109:                if (fp->_r == 0)
                    110:                        fp->_flags |= __SEOF;
                    111:                else {
                    112:                        fp->_r = 0;
                    113:                        fp->_flags |= __SERR;
                    114:                }
                    115:                return (EOF);
                    116:        }
                    117:        return (0);
                    118: }