Libc-262.tar.gz

[apple/libc.git] / stdio / refill.c

diff --git a/stdio/refill.c b/stdio/refill.c
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+++ b/stdio/refill.c
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+/*
+ * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
+ *
+ * @APPLE_LICENSE_HEADER_START@
+ * 
+ * The contents of this file constitute Original Code as defined in and
+ * are subject to the Apple Public Source License Version 1.1 (the
+ * "License").  You may not use this file except in compliance with the
+ * License.  Please obtain a copy of the License at
+ * http://www.apple.com/publicsource and read it before using this file.
+ * 
+ * This Original Code and all software distributed under the License are
+ * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
+ * License for the specific language governing rights and limitations
+ * under the License.
+ * 
+ * @APPLE_LICENSE_HEADER_END@
+ */
+/*
+ * Copyright (c) 1990, 1993
+ *     The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Chris Torek.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *     This product includes software developed by the University of
+ *     California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "local.h"
+
+static int
+lflush(fp)
+       FILE *fp;
+{
+
+       if ((fp->_flags & (__SLBF|__SWR)) == __SLBF|__SWR)
+               return (__sflush(fp));
+       return (0);
+}
+
+/*
+ * Refill a stdio buffer.
+ * Return EOF on eof or error, 0 otherwise.
+ */
+int
+__srefill(fp)
+       register FILE *fp;
+{
+
+       /* make sure stdio is set up */
+       if (!__sdidinit)
+               __sinit();
+
+       fp->_r = 0;             /* largely a convenience for callers */
+
+       /* SysV does not make this test; take it out for compatibility */
+       if (fp->_flags & __SEOF)
+               return (EOF);
+
+       /* if not already reading, have to be reading and writing */
+       if ((fp->_flags & __SRD) == 0) {
+               if ((fp->_flags & __SRW) == 0) {
+                       errno = EBADF;
+                       return (EOF);
+               }
+               /* switch to reading */
+               if (fp->_flags & __SWR) {
+                       if (__sflush(fp))
+                               return (EOF);
+                       fp->_flags &= ~__SWR;
+                       fp->_w = 0;
+                       fp->_lbfsize = 0;
+               }
+               fp->_flags |= __SRD;
+       } else {
+               /*
+                * We were reading.  If there is an ungetc buffer,
+                * we must have been reading from that.  Drop it,
+                * restoring the previous buffer (if any).  If there
+                * is anything in that buffer, return.
+                */
+               if (HASUB(fp)) {
+                       FREEUB(fp);
+                       if ((fp->_r = fp->_ur) != 0) {
+                               fp->_p = fp->_up;
+                               return (0);
+                       }
+               }
+       }
+
+       if (fp->_bf._base == NULL)
+               __smakebuf(fp);
+
+       /*
+        * Before reading from a line buffered or unbuffered file,
+        * flush all line buffered output files, per the ANSI C
+        * standard.
+        */
+       if (fp->_flags & (__SLBF|__SNBF))
+               (void) _fwalk(lflush);
+       fp->_p = fp->_bf._base;
+       fp->_r = (*fp->_read)(fp->_cookie, (char *)fp->_p, fp->_bf._size);
+       fp->_flags &= ~__SMOD;  /* buffer contents are again pristine */
+       if (fp->_r <= 0) {
+               if (fp->_r == 0)
+                       fp->_flags |= __SEOF;
+               else {
+                       fp->_r = 0;
+                       fp->_flags |= __SERR;
+               }
+               return (EOF);
+       }
+       return (0);
+}