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. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #if defined(LIBC_SCCS) && !defined(lint) 38 #if 0 39 static char sccsid[] = "@(#)fgets.c 8.2 (Berkeley) 12/22/93"; 40 #endif 41 static const char rcsid[] = 42 "$FreeBSD$"; 43 #endif /* LIBC_SCCS and not lint */ 44 45 #include "namespace.h" 46 #include <stdio.h> 47 #include <string.h> 48 #include "un-namespace.h" 49 #include "local.h" 50 #include "libc_private.h" 51 52 /* 53 * Read at most n-1 characters from the given file. 54 * Stop when a newline has been read, or the count runs out. 55 * Return first argument, or NULL if no characters were read. 56 */ 57 char * 58 fgets(buf, n, fp) 59 char *buf; 60 register int n; 61 register FILE *fp; 62 { 63 register size_t len; 64 register char *s; 65 register unsigned char *p, *t; 66 67 if (n <= 0) /* sanity check */ 68 return (NULL); 69 70 FLOCKFILE(fp); 71 s = buf; 72 n--; /* leave space for NUL */ 73 while (n != 0) { 74 /* 75 * If the buffer is empty, refill it. 76 */ 77 if ((len = fp->_r) <= 0) { 78 if (__srefill(fp)) { 79 /* EOF/error: stop with partial or no line */ 80 if (s == buf) { 81 FUNLOCKFILE(fp); 82 return (NULL); 83 } 84 break; 85 } 86 len = fp->_r; 87 } 88 p = fp->_p; 89 90 /* 91 * Scan through at most n bytes of the current buffer, 92 * looking for '\n'. If found, copy up to and including 93 * newline, and stop. Otherwise, copy entire chunk 94 * and loop. 95 */ 96 if (len > n) 97 len = n; 98 t = memchr((void *)p, '\n', len); 99 if (t != NULL) { 100 len = ++t - p; 101 fp->_r -= len; 102 fp->_p = t; 103 (void)memcpy((void *)s, (void *)p, len); 104 s[len] = 0; 105 FUNLOCKFILE(fp); 106 return (buf); 107 } 108 fp->_r -= len; 109 fp->_p += len; 110 (void)memcpy((void *)s, (void *)p, len); 111 s += len; 112 n -= len; 113 } 114 *s = 0; 115 FUNLOCKFILE(fp); 116 return (buf); 117 } 118