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. 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 */ 35 36 #include "namespace.h" 37 #include <stdio.h> 38 #include <stdlib.h> 39 #include <string.h> 40 #include "un-namespace.h" 41 42 #include "libc_private.h" 43 #include "local.h" 44 45 /* 46 * Expand the line buffer. Return -1 on error. 47 #ifdef notdef 48 * The `new size' does not account for a terminating '\0', 49 * so we add 1 here. 50 #endif 51 */ 52 int 53 __slbexpand(FILE *fp, size_t newsize) 54 { 55 void *p; 56 57 #ifdef notdef 58 ++newsize; 59 #endif 60 if (fp->_lb._size >= newsize) 61 return (0); 62 if ((p = realloc(fp->_lb._base, newsize)) == NULL) 63 return (-1); 64 fp->_lb._base = p; 65 fp->_lb._size = newsize; 66 return (0); 67 } 68 69 /* 70 * Get an input line. The returned pointer often (but not always) 71 * points into a stdio buffer. Fgetln does not alter the text of 72 * the returned line (which is thus not a C string because it will 73 * not necessarily end with '\0'), but does allow callers to modify 74 * it if they wish. Thus, we set __SMOD in case the caller does. 75 */ 76 char * 77 fgetln(FILE *fp, size_t *lenp) 78 { 79 unsigned char *p; 80 size_t len; 81 size_t off; 82 83 FLOCKFILE(fp); 84 ORIENT(fp, -1); 85 /* make sure there is input */ 86 if (fp->pub._r <= 0 && __srefill(fp)) { 87 *lenp = 0; 88 FUNLOCKFILE(fp); 89 return (NULL); 90 } 91 92 /* look for a newline in the input */ 93 if ((p = memchr((void *)fp->pub._p, '\n', (size_t)fp->pub._r)) != NULL) { 94 char *ret; 95 96 /* 97 * Found one. Flag buffer as modified to keep fseek from 98 * `optimising' a backward seek, in case the user stomps on 99 * the text. 100 */ 101 p++; /* advance over it */ 102 ret = (char *)fp->pub._p; 103 *lenp = len = p - fp->pub._p; 104 fp->pub._flags |= __SMOD; 105 fp->pub._r -= len; 106 fp->pub._p = p; 107 FUNLOCKFILE(fp); 108 return (ret); 109 } 110 111 /* 112 * We have to copy the current buffered data to the line buffer. 113 * As a bonus, though, we can leave off the __SMOD. 114 * 115 * OPTIMISTIC is length that we (optimistically) expect will 116 * accomodate the `rest' of the string, on each trip through the 117 * loop below. 118 */ 119 #define OPTIMISTIC 80 120 121 for (len = fp->pub._r, off = 0;; len += fp->pub._r) { 122 size_t diff; 123 124 /* 125 * Make sure there is room for more bytes. Copy data from 126 * file buffer to line buffer, refill file and look for 127 * newline. The loop stops only when we find a newline. 128 */ 129 if (__slbexpand(fp, len + OPTIMISTIC)) 130 goto error; 131 memcpy((void *)(fp->_lb._base + off), (void *)fp->pub._p, 132 len - off); 133 off = len; 134 if (__srefill(fp)) 135 break; /* EOF or error: return partial line */ 136 if ((p = memchr((void *)fp->pub._p, '\n', (size_t)fp->pub._r)) 137 == NULL) 138 continue; 139 140 /* got it: finish up the line (like code above) */ 141 p++; 142 diff = p - fp->pub._p; 143 len += diff; 144 if (__slbexpand(fp, len)) 145 goto error; 146 memcpy((void *)(fp->_lb._base + off), (void *)fp->pub._p, diff); 147 fp->pub._r -= diff; 148 fp->pub._p = p; 149 break; 150 } 151 *lenp = len; 152 #ifdef notdef 153 fp->_lb._base[len] = 0; 154 #endif 155 FUNLOCKFILE(fp); 156 return ((char *)fp->_lb._base); 157 158 error: 159 *lenp = 0; /* ??? */ 160 FUNLOCKFILE(fp); 161 return (NULL); /* ??? */ 162 } 163