1 /* $OpenBSD: freadptr.c,v 1.1 2024/08/12 20:56:55 guenther Exp $ */ 2 /* 3 * Copyright (c) 2024 Philip Guenther <guenther@openbsd.org> 4 * 5 * Permission to use, copy, modify, and distribute this software for any 6 * purpose with or without fee is hereby granted, provided that the above 7 * copyright notice and this permission notice appear in all copies. 8 * 9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16 */ 17 18 #include <stdlib.h> 19 #include <stdio_ext.h> 20 #include "local.h" 21 22 const char * 23 __freadptr(FILE *fp, size_t *sizep) 24 { 25 if ((fp->_flags & __SRD) && fp->_r > 0) { 26 *sizep = fp->_r; 27 return fp->_p; 28 } 29 return NULL; 30 } 31 32 void 33 __freadptrinc(FILE *fp, size_t inc) 34 { 35 if (fp->_flags & __SRD) { 36 fp->_r -= inc; 37 fp->_p += inc; 38 if (fp->_r == 0 && HASUB(fp)) { 39 /* consumed the pushback buffer; switch back */ 40 FREEUB(fp); 41 if ((fp->_r = fp->_ur) != 0) 42 fp->_p = fp->_up; 43 } 44 } 45 } 46