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 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * @(#)fgetln.c 8.2 (Berkeley) 1/2/94 33 * $FreeBSD: src/lib/libc/stdio/fgetln.c,v 1.11 2007/01/09 00:28:06 imp Exp $ 34 * $DragonFly: src/lib/libc/stdio/fgetln.c,v 1.7 2005/11/20 11:07:30 swildner Exp $ 35 */ 36 37 #include "namespace.h" 38 #include <stdio.h> 39 #include <stdlib.h> 40 #include <string.h> 41 #include "un-namespace.h" 42 43 #include "libc_private.h" 44 #include "local.h" 45 #include "priv_stdio.h" 46 47 /* 48 * Expand the line buffer. Return -1 on error. 49 #ifdef notdef 50 * The `new size' does not account for a terminating '\0', 51 * so we add 1 here. 52 #endif 53 */ 54 int 55 __slbexpand(FILE *fp, size_t newsize) 56 { 57 void *p; 58 59 #ifdef notdef 60 ++newsize; 61 #endif 62 if (fp->_lb._size >= newsize) 63 return (0); 64 if ((p = realloc(fp->_lb._base, newsize)) == NULL) 65 return (-1); 66 fp->_lb._base = p; 67 fp->_lb._size = newsize; 68 return (0); 69 } 70 71 /* 72 * Get an input line. The returned pointer often (but not always) 73 * points into a stdio buffer. Fgetln does not alter the text of 74 * the returned line (which is thus not a C string because it will 75 * not necessarily end with '\0'), but does allow callers to modify 76 * it if they wish. Thus, we set __SMOD in case the caller does. 77 */ 78 char * 79 fgetln(FILE *fp, size_t *lenp) 80 { 81 unsigned char *p; 82 size_t len; 83 size_t off; 84 85 FLOCKFILE(fp); 86 ORIENT(fp, -1); 87 /* make sure there is input */ 88 if (fp->pub._r <= 0 && __srefill(fp)) { 89 *lenp = 0; 90 FUNLOCKFILE(fp); 91 return (NULL); 92 } 93 94 /* look for a newline in the input */ 95 if ((p = memchr((void *)fp->pub._p, '\n', (size_t)fp->pub._r)) != NULL) { 96 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->pub._p; 105 *lenp = len = p - fp->pub._p; 106 fp->pub._flags |= __SMOD; 107 fp->pub._r -= len; 108 fp->pub._p = p; 109 FUNLOCKFILE(fp); 110 return (ret); 111 } 112 113 /* 114 * We have to copy the current buffered data to the line buffer. 115 * As a bonus, though, we can leave off the __SMOD. 116 * 117 * OPTIMISTIC is length that we (optimistically) expect will 118 * accomodate the `rest' of the string, on each trip through the 119 * loop below. 120 */ 121 #define OPTIMISTIC 80 122 123 for (len = fp->pub._r, off = 0;; len += fp->pub._r) { 124 size_t diff; 125 126 /* 127 * Make sure there is room for more bytes. Copy data from 128 * file buffer to line buffer, refill file and look for 129 * newline. The loop stops only when we find a newline. 130 */ 131 if (__slbexpand(fp, len + OPTIMISTIC)) 132 goto error; 133 memcpy((void *)(fp->_lb._base + off), (void *)fp->pub._p, 134 len - off); 135 off = len; 136 if (__srefill(fp)) 137 break; /* EOF or error: return partial line */ 138 if ((p = memchr((void *)fp->pub._p, '\n', (size_t)fp->pub._r)) 139 == NULL) 140 continue; 141 142 /* got it: finish up the line (like code above) */ 143 p++; 144 diff = p - fp->pub._p; 145 len += diff; 146 if (__slbexpand(fp, len)) 147 goto error; 148 memcpy((void *)(fp->_lb._base + off), (void *)fp->pub._p, diff); 149 fp->pub._r -= diff; 150 fp->pub._p = p; 151 break; 152 } 153 *lenp = len; 154 #ifdef notdef 155 fp->_lb._base[len] = 0; 156 #endif 157 FUNLOCKFILE(fp); 158 return ((char *)fp->_lb._base); 159 160 error: 161 *lenp = 0; /* ??? */ 162 FUNLOCKFILE(fp); 163 return (NULL); /* ??? */ 164 } 165