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 * @(#)fgetln.c 8.2 (Berkeley) 1/2/94 37 * $FreeBSD: src/lib/libc/stdio/fgetln.c,v 1.6 1999/08/28 00:00:59 peter Exp $ 38 * $DragonFly: src/lib/libc/stdio/fgetln.c,v 1.2 2003/06/17 04:26:45 dillon Exp $ 39 */ 40 41 #include <stdio.h> 42 #include <stdlib.h> 43 #include <string.h> 44 #include "local.h" 45 46 /* 47 * Expand the line buffer. Return -1 on error. 48 #ifdef notdef 49 * The `new size' does not account for a terminating '\0', 50 * so we add 1 here. 51 #endif 52 */ 53 int 54 __slbexpand(fp, newsize) 55 FILE *fp; 56 size_t newsize; 57 { 58 void *p; 59 60 #ifdef notdef 61 ++newsize; 62 #endif 63 if (fp->_lb._size >= newsize) 64 return (0); 65 if ((p = realloc(fp->_lb._base, newsize)) == NULL) 66 return (-1); 67 fp->_lb._base = p; 68 fp->_lb._size = newsize; 69 return (0); 70 } 71 72 /* 73 * Get an input line. The returned pointer often (but not always) 74 * points into a stdio buffer. Fgetln does not alter the text of 75 * the returned line (which is thus not a C string because it will 76 * not necessarily end with '\0'), but does allow callers to modify 77 * it if they wish. Thus, we set __SMOD in case the caller does. 78 */ 79 char * 80 fgetln(fp, lenp) 81 register FILE *fp; 82 size_t *lenp; 83 { 84 register unsigned char *p; 85 register size_t len; 86 size_t off; 87 88 /* make sure there is input */ 89 if (fp->_r <= 0 && __srefill(fp)) { 90 *lenp = 0; 91 return (NULL); 92 } 93 94 /* look for a newline in the input */ 95 if ((p = memchr((void *)fp->_p, '\n', (size_t)fp->_r)) != NULL) { 96 register char *ret; 97 98 /* 99 * Found one. Flag buffer as modified to keep fseek from 100 * `optimising' a backward seek, in case the user stomps on 101 * the text. 102 */ 103 p++; /* advance over it */ 104 ret = (char *)fp->_p; 105 *lenp = len = p - fp->_p; 106 fp->_flags |= __SMOD; 107 fp->_r -= len; 108 fp->_p = p; 109 return (ret); 110 } 111 112 /* 113 * We have to copy the current buffered data to the line buffer. 114 * As a bonus, though, we can leave off the __SMOD. 115 * 116 * OPTIMISTIC is length that we (optimistically) expect will 117 * accomodate the `rest' of the string, on each trip through the 118 * loop below. 119 */ 120 #define OPTIMISTIC 80 121 122 for (len = fp->_r, off = 0;; len += fp->_r) { 123 register size_t diff; 124 125 /* 126 * Make sure there is room for more bytes. Copy data from 127 * file buffer to line buffer, refill file and look for 128 * newline. The loop stops only when we find a newline. 129 */ 130 if (__slbexpand(fp, len + OPTIMISTIC)) 131 goto error; 132 (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_p, 133 len - off); 134 off = len; 135 if (__srefill(fp)) 136 break; /* EOF or error: return partial line */ 137 if ((p = memchr((void *)fp->_p, '\n', (size_t)fp->_r)) == NULL) 138 continue; 139 140 /* got it: finish up the line (like code above) */ 141 p++; 142 diff = p - fp->_p; 143 len += diff; 144 if (__slbexpand(fp, len)) 145 goto error; 146 (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_p, 147 diff); 148 fp->_r -= diff; 149 fp->_p = p; 150 break; 151 } 152 *lenp = len; 153 #ifdef notdef 154 fp->_lb._base[len] = 0; 155 #endif 156 return ((char *)fp->_lb._base); 157 158 error: 159 *lenp = 0; /* ??? */ 160 return (NULL); /* ??? */ 161 } 162