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 static char sccsid[] = "@(#)fgetln.c 8.2 (Berkeley) 1/2/94"; 39 #endif /* LIBC_SCCS and not lint */ 40 #include <sys/cdefs.h> 41 __FBSDID("$FreeBSD$"); 42 43 #include "namespace.h" 44 #include <stdio.h> 45 #include <stdlib.h> 46 #include <string.h> 47 #include "un-namespace.h" 48 #include "libc_private.h" 49 #include "local.h" 50 51 /* 52 * Expand the line buffer. Return -1 on error. 53 #ifdef notdef 54 * The `new size' does not account for a terminating '\0', 55 * so we add 1 here. 56 #endif 57 */ 58 static int 59 slbexpand(FILE *fp, size_t newsize) 60 { 61 void *p; 62 63 #ifdef notdef 64 ++newsize; 65 #endif 66 if (fp->_lb._size >= newsize) 67 return (0); 68 if ((p = realloc(fp->_lb._base, newsize)) == NULL) 69 return (-1); 70 fp->_lb._base = p; 71 fp->_lb._size = newsize; 72 return (0); 73 } 74 75 /* 76 * Get an input line. The returned pointer often (but not always) 77 * points into a stdio buffer. Fgetln does not alter the text of 78 * the returned line (which is thus not a C string because it will 79 * not necessarily end with '\0'), but does allow callers to modify 80 * it if they wish. Thus, we set __SMOD in case the caller does. 81 */ 82 char * 83 fgetln(FILE *fp, size_t *lenp) 84 { 85 unsigned char *p; 86 size_t len; 87 size_t off; 88 89 FLOCKFILE(fp); 90 /* make sure there is input */ 91 if (fp->_r <= 0 && __srefill(fp)) { 92 *lenp = 0; 93 FUNLOCKFILE(fp); 94 return (NULL); 95 } 96 97 /* look for a newline in the input */ 98 if ((p = memchr((void *)fp->_p, '\n', (size_t)fp->_r)) != NULL) { 99 char *ret; 100 101 /* 102 * Found one. Flag buffer as modified to keep fseek from 103 * `optimising' a backward seek, in case the user stomps on 104 * the text. 105 */ 106 p++; /* advance over it */ 107 ret = (char *)fp->_p; 108 *lenp = len = p - fp->_p; 109 fp->_flags |= __SMOD; 110 fp->_r -= len; 111 fp->_p = p; 112 FUNLOCKFILE(fp); 113 return (ret); 114 } 115 116 /* 117 * We have to copy the current buffered data to the line buffer. 118 * As a bonus, though, we can leave off the __SMOD. 119 * 120 * OPTIMISTIC is length that we (optimistically) expect will 121 * accomodate the `rest' of the string, on each trip through the 122 * loop below. 123 */ 124 #define OPTIMISTIC 80 125 126 for (len = fp->_r, off = 0;; len += fp->_r) { 127 size_t diff; 128 129 /* 130 * Make sure there is room for more bytes. Copy data from 131 * file buffer to line buffer, refill file and look for 132 * newline. The loop stops only when we find a newline. 133 */ 134 if (slbexpand(fp, len + OPTIMISTIC)) 135 goto error; 136 (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_p, 137 len - off); 138 off = len; 139 if (__srefill(fp)) 140 break; /* EOF or error: return partial line */ 141 if ((p = memchr((void *)fp->_p, '\n', (size_t)fp->_r)) == NULL) 142 continue; 143 144 /* got it: finish up the line (like code above) */ 145 p++; 146 diff = p - fp->_p; 147 len += diff; 148 if (slbexpand(fp, len)) 149 goto error; 150 (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_p, 151 diff); 152 fp->_r -= diff; 153 fp->_p = p; 154 break; 155 } 156 *lenp = len; 157 #ifdef notdef 158 fp->_lb._base[len] = 0; 159 #endif 160 FUNLOCKFILE(fp); 161 return ((char *)fp->_lb._base); 162 163 error: 164 *lenp = 0; /* ??? */ 165 FUNLOCKFILE(fp); 166 return (NULL); /* ??? */ 167 } 168