158f0484fSRodney W. Grimes /*- 258f0484fSRodney W. Grimes * Copyright (c) 1990, 1993 358f0484fSRodney W. Grimes * The Regents of the University of California. All rights reserved. 458f0484fSRodney W. Grimes * 558f0484fSRodney W. Grimes * This code is derived from software contributed to Berkeley by 658f0484fSRodney W. Grimes * Chris Torek. 758f0484fSRodney W. Grimes * 858f0484fSRodney W. Grimes * Redistribution and use in source and binary forms, with or without 958f0484fSRodney W. Grimes * modification, are permitted provided that the following conditions 1058f0484fSRodney W. Grimes * are met: 1158f0484fSRodney W. Grimes * 1. Redistributions of source code must retain the above copyright 1258f0484fSRodney W. Grimes * notice, this list of conditions and the following disclaimer. 1358f0484fSRodney W. Grimes * 2. Redistributions in binary form must reproduce the above copyright 1458f0484fSRodney W. Grimes * notice, this list of conditions and the following disclaimer in the 1558f0484fSRodney W. Grimes * documentation and/or other materials provided with the distribution. 1658f0484fSRodney W. Grimes * 3. All advertising materials mentioning features or use of this software 1758f0484fSRodney W. Grimes * must display the following acknowledgement: 1858f0484fSRodney W. Grimes * This product includes software developed by the University of 1958f0484fSRodney W. Grimes * California, Berkeley and its contributors. 2058f0484fSRodney W. Grimes * 4. Neither the name of the University nor the names of its contributors 2158f0484fSRodney W. Grimes * may be used to endorse or promote products derived from this software 2258f0484fSRodney W. Grimes * without specific prior written permission. 2358f0484fSRodney W. Grimes * 2458f0484fSRodney W. Grimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 2558f0484fSRodney W. Grimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 2658f0484fSRodney W. Grimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 2758f0484fSRodney W. Grimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 2858f0484fSRodney W. Grimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 2958f0484fSRodney W. Grimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 3058f0484fSRodney W. Grimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 3158f0484fSRodney W. Grimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 3258f0484fSRodney W. Grimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 3358f0484fSRodney W. Grimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 3458f0484fSRodney W. Grimes * SUCH DAMAGE. 3558f0484fSRodney W. Grimes */ 3658f0484fSRodney W. Grimes 3758f0484fSRodney W. Grimes #if defined(LIBC_SCCS) && !defined(lint) 3858f0484fSRodney W. Grimes static char sccsid[] = "@(#)ungetc.c 8.2 (Berkeley) 11/3/93"; 3958f0484fSRodney W. Grimes #endif /* LIBC_SCCS and not lint */ 40333fc21eSDavid E. O'Brien #include <sys/cdefs.h> 41333fc21eSDavid E. O'Brien __FBSDID("$FreeBSD$"); 4258f0484fSRodney W. Grimes 43d201fe46SDaniel Eischen #include "namespace.h" 4458f0484fSRodney W. Grimes #include <stdio.h> 4558f0484fSRodney W. Grimes #include <stdlib.h> 4658f0484fSRodney W. Grimes #include <string.h> 47d201fe46SDaniel Eischen #include "un-namespace.h" 4858f0484fSRodney W. Grimes #include "local.h" 49ec216c26SJohn Birrell #include "libc_private.h" 5058f0484fSRodney W. Grimes 51c05ac53bSDavid E. O'Brien static int __submore(FILE *); 52ce51cf03SJames Raynard 5358f0484fSRodney W. Grimes /* 5458f0484fSRodney W. Grimes * Expand the ungetc buffer `in place'. That is, adjust fp->_p when 5558f0484fSRodney W. Grimes * the buffer moves, so that it points the same distance from the end, 5658f0484fSRodney W. Grimes * and move the bytes in the buffer around as necessary so that they 5758f0484fSRodney W. Grimes * are all at the end (stack-style). 5858f0484fSRodney W. Grimes */ 59f70177e7SJulian Elischer static int 60d201fe46SDaniel Eischen __submore(FILE *fp) 6158f0484fSRodney W. Grimes { 62d201fe46SDaniel Eischen int i; 63d201fe46SDaniel Eischen unsigned char *p; 6458f0484fSRodney W. Grimes 6558f0484fSRodney W. Grimes if (fp->_ub._base == fp->_ubuf) { 6658f0484fSRodney W. Grimes /* 6758f0484fSRodney W. Grimes * Get a new buffer (rather than expanding the old one). 6858f0484fSRodney W. Grimes */ 6958f0484fSRodney W. Grimes if ((p = malloc((size_t)BUFSIZ)) == NULL) 7058f0484fSRodney W. Grimes return (EOF); 7158f0484fSRodney W. Grimes fp->_ub._base = p; 7258f0484fSRodney W. Grimes fp->_ub._size = BUFSIZ; 7358f0484fSRodney W. Grimes p += BUFSIZ - sizeof(fp->_ubuf); 7458f0484fSRodney W. Grimes for (i = sizeof(fp->_ubuf); --i >= 0;) 7558f0484fSRodney W. Grimes p[i] = fp->_ubuf[i]; 7658f0484fSRodney W. Grimes fp->_p = p; 7758f0484fSRodney W. Grimes return (0); 7858f0484fSRodney W. Grimes } 7958f0484fSRodney W. Grimes i = fp->_ub._size; 80ce51cf03SJames Raynard p = realloc(fp->_ub._base, (size_t)(i << 1)); 8158f0484fSRodney W. Grimes if (p == NULL) 8258f0484fSRodney W. Grimes return (EOF); 8358f0484fSRodney W. Grimes /* no overlap (hence can use memcpy) because we doubled the size */ 8458f0484fSRodney W. Grimes (void)memcpy((void *)(p + i), (void *)p, (size_t)i); 8558f0484fSRodney W. Grimes fp->_p = p + i; 8658f0484fSRodney W. Grimes fp->_ub._base = p; 8758f0484fSRodney W. Grimes fp->_ub._size = i << 1; 8858f0484fSRodney W. Grimes return (0); 8958f0484fSRodney W. Grimes } 9058f0484fSRodney W. Grimes 91d201fe46SDaniel Eischen /* 92d201fe46SDaniel Eischen * MT-safe version 93d201fe46SDaniel Eischen */ 94f70177e7SJulian Elischer int 95d201fe46SDaniel Eischen ungetc(int c, FILE *fp) 9658f0484fSRodney W. Grimes { 97d201fe46SDaniel Eischen int ret; 98d201fe46SDaniel Eischen 9958f0484fSRodney W. Grimes if (c == EOF) 10058f0484fSRodney W. Grimes return (EOF); 10158f0484fSRodney W. Grimes if (!__sdidinit) 10258f0484fSRodney W. Grimes __sinit(); 103ec216c26SJohn Birrell FLOCKFILE(fp); 104d201fe46SDaniel Eischen ret = __ungetc(c, fp); 105d201fe46SDaniel Eischen FUNLOCKFILE(fp); 106d201fe46SDaniel Eischen return (ret); 107d201fe46SDaniel Eischen } 108d201fe46SDaniel Eischen 109d201fe46SDaniel Eischen /* 110d201fe46SDaniel Eischen * Non-MT-safe version 111d201fe46SDaniel Eischen */ 112d201fe46SDaniel Eischen int 113d201fe46SDaniel Eischen __ungetc(int c, FILE *fp) 114d201fe46SDaniel Eischen { 115e74101e4STim J. Robbins 116e74101e4STim J. Robbins ORIENT(fp, -1); 117e74101e4STim J. Robbins 118d201fe46SDaniel Eischen if (c == EOF) 119d201fe46SDaniel Eischen return (EOF); 12058f0484fSRodney W. Grimes if ((fp->_flags & __SRD) == 0) { 12158f0484fSRodney W. Grimes /* 12258f0484fSRodney W. Grimes * Not already reading: no good unless reading-and-writing. 12358f0484fSRodney W. Grimes * Otherwise, flush any current write stuff. 12458f0484fSRodney W. Grimes */ 125d201fe46SDaniel Eischen if ((fp->_flags & __SRW) == 0) 12658f0484fSRodney W. Grimes return (EOF); 12758f0484fSRodney W. Grimes if (fp->_flags & __SWR) { 128d201fe46SDaniel Eischen if (__sflush(fp)) 12958f0484fSRodney W. Grimes return (EOF); 13058f0484fSRodney W. Grimes fp->_flags &= ~__SWR; 13158f0484fSRodney W. Grimes fp->_w = 0; 13258f0484fSRodney W. Grimes fp->_lbfsize = 0; 13358f0484fSRodney W. Grimes } 13458f0484fSRodney W. Grimes fp->_flags |= __SRD; 13558f0484fSRodney W. Grimes } 13658f0484fSRodney W. Grimes c = (unsigned char)c; 13758f0484fSRodney W. Grimes 13858f0484fSRodney W. Grimes /* 13958f0484fSRodney W. Grimes * If we are in the middle of ungetc'ing, just continue. 14058f0484fSRodney W. Grimes * This may require expanding the current ungetc buffer. 14158f0484fSRodney W. Grimes */ 14258f0484fSRodney W. Grimes if (HASUB(fp)) { 143d201fe46SDaniel Eischen if (fp->_r >= fp->_ub._size && __submore(fp)) 14458f0484fSRodney W. Grimes return (EOF); 14558f0484fSRodney W. Grimes *--fp->_p = c; 14658f0484fSRodney W. Grimes fp->_r++; 14758f0484fSRodney W. Grimes return (c); 14858f0484fSRodney W. Grimes } 14958f0484fSRodney W. Grimes fp->_flags &= ~__SEOF; 15058f0484fSRodney W. Grimes 15158f0484fSRodney W. Grimes /* 15258f0484fSRodney W. Grimes * If we can handle this by simply backing up, do so, 15358f0484fSRodney W. Grimes * but never replace the original character. 15458f0484fSRodney W. Grimes * (This makes sscanf() work when scanning `const' data.) 15558f0484fSRodney W. Grimes */ 15658f0484fSRodney W. Grimes if (fp->_bf._base != NULL && fp->_p > fp->_bf._base && 15758f0484fSRodney W. Grimes fp->_p[-1] == c) { 15858f0484fSRodney W. Grimes fp->_p--; 15958f0484fSRodney W. Grimes fp->_r++; 16058f0484fSRodney W. Grimes return (c); 16158f0484fSRodney W. Grimes } 16258f0484fSRodney W. Grimes 16358f0484fSRodney W. Grimes /* 16458f0484fSRodney W. Grimes * Create an ungetc buffer. 16558f0484fSRodney W. Grimes * Initially, we will use the `reserve' buffer. 16658f0484fSRodney W. Grimes */ 16758f0484fSRodney W. Grimes fp->_ur = fp->_r; 16891e1be28SWarner Losh fp->_extra->_up = fp->_p; 16958f0484fSRodney W. Grimes fp->_ub._base = fp->_ubuf; 17058f0484fSRodney W. Grimes fp->_ub._size = sizeof(fp->_ubuf); 17158f0484fSRodney W. Grimes fp->_ubuf[sizeof(fp->_ubuf) - 1] = c; 17258f0484fSRodney W. Grimes fp->_p = &fp->_ubuf[sizeof(fp->_ubuf) - 1]; 17358f0484fSRodney W. Grimes fp->_r = 1; 17458f0484fSRodney W. Grimes return (c); 17558f0484fSRodney W. Grimes } 176