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[] = "@(#)fgetln.c 8.2 (Berkeley) 1/2/94"; 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 <stdlib.h> 48 #include <string.h> 49 #include "un-namespace.h" 50 #include "libc_private.h" 51 #include "local.h" 52 53 /* 54 * Expand the line buffer. Return -1 on error. 55 #ifdef notdef 56 * The `new size' does not account for a terminating '\0', 57 * so we add 1 here. 58 #endif 59 */ 60 static int 61 slbexpand(FILE *fp, size_t newsize) 62 { 63 void *p; 64 65 #ifdef notdef 66 ++newsize; 67 #endif 68 if (fp->_lb._size >= newsize) 69 return (0); 70 if ((p = realloc(fp->_lb._base, newsize)) == NULL) 71 return (-1); 72 fp->_lb._base = p; 73 fp->_lb._size = newsize; 74 return (0); 75 } 76 77 /* 78 * Get an input line. The returned pointer often (but not always) 79 * points into a stdio buffer. Fgetln does not alter the text of 80 * the returned line (which is thus not a C string because it will 81 * not necessarily end with '\0'), but does allow callers to modify 82 * it if they wish. Thus, we set __SMOD in case the caller does. 83 */ 84 char * 85 fgetln(FILE *fp, size_t *lenp) 86 { 87 unsigned char *p; 88 size_t len; 89 size_t off; 90 91 FLOCKFILE(fp); 92 /* make sure there is input */ 93 if (fp->_r <= 0 && __srefill(fp)) { 94 *lenp = 0; 95 FUNLOCKFILE(fp); 96 return (NULL); 97 } 98 99 /* look for a newline in the input */ 100 if ((p = memchr((void *)fp->_p, '\n', (size_t)fp->_r)) != NULL) { 101 char *ret; 102 103 /* 104 * Found one. Flag buffer as modified to keep fseek from 105 * `optimising' a backward seek, in case the user stomps on 106 * the text. 107 */ 108 p++; /* advance over it */ 109 ret = (char *)fp->_p; 110 *lenp = len = p - fp->_p; 111 fp->_flags |= __SMOD; 112 fp->_r -= len; 113 fp->_p = p; 114 FUNLOCKFILE(fp); 115 return (ret); 116 } 117 118 /* 119 * We have to copy the current buffered data to the line buffer. 120 * As a bonus, though, we can leave off the __SMOD. 121 * 122 * OPTIMISTIC is length that we (optimistically) expect will 123 * accomodate the `rest' of the string, on each trip through the 124 * loop below. 125 */ 126 #define OPTIMISTIC 80 127 128 for (len = fp->_r, off = 0;; len += fp->_r) { 129 size_t diff; 130 131 /* 132 * Make sure there is room for more bytes. Copy data from 133 * file buffer to line buffer, refill file and look for 134 * newline. The loop stops only when we find a newline. 135 */ 136 if (slbexpand(fp, len + OPTIMISTIC)) 137 goto error; 138 (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_p, 139 len - off); 140 off = len; 141 if (__srefill(fp)) 142 break; /* EOF or error: return partial line */ 143 if ((p = memchr((void *)fp->_p, '\n', (size_t)fp->_r)) == NULL) 144 continue; 145 146 /* got it: finish up the line (like code above) */ 147 p++; 148 diff = p - fp->_p; 149 len += diff; 150 if (slbexpand(fp, len)) 151 goto error; 152 (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_p, 153 diff); 154 fp->_r -= diff; 155 fp->_p = p; 156 break; 157 } 158 *lenp = len; 159 #ifdef notdef 160 fp->_lb._base[len] = 0; 161 #endif 162 FUNLOCKFILE(fp); 163 return ((char *)fp->_lb._base); 164 165 error: 166 *lenp = 0; /* ??? */ 167 FUNLOCKFILE(fp); 168 return (NULL); /* ??? */ 169 } 170