-/*-
- * 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.
- */
-
-#if defined(LIBC_SCCS) && !defined(lint)
-static char sccsid[] = "@(#)ungetc.c 8.2 (Berkeley) 11/3/93";
-#endif /* LIBC_SCCS and not lint */
-#include <sys/cdefs.h>
-__FBSDID("$FreeBSD: src/lib/libc/stdio/ungetc.c,v 1.16 2004/03/10 12:41:11 tjr Exp $");
-
-#include "namespace.h"
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include "un-namespace.h"
-#include "local.h"
-#include "libc_private.h"
-
-static int __submore(FILE *);
-
-/*
- * Expand the ungetc buffer `in place'. That is, adjust fp->_p when
- * the buffer moves, so that it points the same distance from the end,
- * and move the bytes in the buffer around as necessary so that they
- * are all at the end (stack-style).
- */
-static int
-__submore(FILE *fp)
-{
- int i;
- unsigned char *p;
-
- if (fp->_ub._base == fp->_ubuf) {
- /*
- * Get a new buffer (rather than expanding the old one).
- */
- if ((p = malloc((size_t)BUFSIZ)) == NULL)
- return (EOF);
- fp->_ub._base = p;
- fp->_ub._size = BUFSIZ;
- p += BUFSIZ - sizeof(fp->_ubuf);
- for (i = sizeof(fp->_ubuf); --i >= 0;)
- p[i] = fp->_ubuf[i];
- fp->_p = p;
- return (0);
- }
- i = fp->_ub._size;
- p = realloc(fp->_ub._base, (size_t)(i << 1));
- if (p == NULL)
- return (EOF);
- /* no overlap (hence can use memcpy) because we doubled the size */
- (void)memcpy((void *)(p + i), (void *)p, (size_t)i);
- fp->_p = p + i;
- fp->_ub._base = p;
- fp->_ub._size = i << 1;
- return (0);
-}
-
-/*
- * MT-safe version
- */
-int
-ungetc(int c, FILE *fp)
-{
- int ret;
-
- if (!__sdidinit)
- __sinit();
- FLOCKFILE(fp);
- ORIENT(fp, -1);
- ret = __ungetc(c, fp);
- FUNLOCKFILE(fp);
- return (ret);
-}
-
-/*
- * Non-MT-safe version
- */
-int
-__ungetc(int c, FILE *fp)
-{
-
- if (c == EOF)
- return (EOF);
- if ((fp->_flags & __SRD) == 0) {
- /*
- * Not already reading: no good unless reading-and-writing.
- * Otherwise, flush any current write stuff.
- */
- if ((fp->_flags & __SRW) == 0)
- return (EOF);
- if (fp->_flags & __SWR) {
- if (__sflush(fp))
- return (EOF);
- fp->_flags &= ~__SWR;
- fp->_w = 0;
- fp->_lbfsize = 0;
- }
- fp->_flags |= __SRD;
- }
- c = (unsigned char)c;
-
- /*
- * If we are in the middle of ungetc'ing, just continue.
- * This may require expanding the current ungetc buffer.
- */
- if (HASUB(fp)) {
- if (fp->_r >= fp->_ub._size && __submore(fp))
- return (EOF);
- *--fp->_p = c;
- fp->_r++;
- return (c);
- }
- fp->_flags &= ~__SEOF;
-
- /*
- * If we can handle this by simply backing up, do so,
- * but never replace the original character.
- * (This makes sscanf() work when scanning `const' data.)
- */
- if (fp->_bf._base != NULL && fp->_p > fp->_bf._base &&
- fp->_p[-1] == c) {
- fp->_p--;
- fp->_r++;
- return (c);
- }
-
- /*
- * Create an ungetc buffer.
- * Initially, we will use the `reserve' buffer.
- */
- fp->_ur = fp->_r;
- fp->_extra->_up = fp->_p;
- fp->_ub._base = fp->_ubuf;
- fp->_ub._size = sizeof(fp->_ubuf);
- fp->_ubuf[sizeof(fp->_ubuf) - 1] = c;
- fp->_p = &fp->_ubuf[sizeof(fp->_ubuf) - 1];
- fp->_r = 1;
- return (c);
-}
projects / apple / libc.git / blobdiff