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 <stdio.h> 46 #include <stdlib.h> 47 #include <string.h> 48 #include "local.h" 49 50 /* 51 * Expand the line buffer. Return -1 on error. 52 #ifdef notdef 53 * The `new size' does not account for a terminating '\0', 54 * so we add 1 here. 55 #endif 56 */ 57 int 58 __slbexpand(fp, newsize) 59 FILE *fp; 60 size_t newsize; 61 { 62 void *p; 63 64 #ifdef notdef 65 ++newsize; 66 #endif 67 if (fp->_lb._size >= newsize) 68 return (0); 69 if ((p = realloc(fp->_lb._base, newsize)) == NULL) 70 return (-1); 71 fp->_lb._base = p; 72 fp->_lb._size = newsize; 73 return (0); 74 } 75 76 /* 77 * Get an input line. The returned pointer often (but not always) 78 * points into a stdio buffer. Fgetln does not alter the text of 79 * the returned line (which is thus not a C string because it will 80 * not necessarily end with '\0'), but does allow callers to modify 81 * it if they wish. Thus, we set __SMOD in case the caller does. 82 */ 83 char * 84 fgetln(fp, lenp) 85 register FILE *fp; 86 size_t *lenp; 87 { 88 register unsigned char *p; 89 register size_t len; 90 size_t off; 91 92 /* make sure there is input */ 93 if (fp->_r <= 0 && __srefill(fp)) { 94 *lenp = 0; 95 return (NULL); 96 } 97 98 /* look for a newline in the input */ 99 if ((p = memchr((void *)fp->_p, '\n', (size_t)fp->_r)) != NULL) { 100 register char *ret; 101 102 /* 103 * Found one. Flag buffer as modified to keep fseek from 104 * `optimising' a backward seek, in case the user stomps on 105 * the text. 106 */ 107 p++; /* advance over it */ 108 ret = (char *)fp->_p; 109 *lenp = len = p - fp->_p; 110 fp->_flags |= __SMOD; 111 fp->_r -= len; 112 fp->_p = p; 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 register 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 return ((char *)fp->_lb._base); 161 162 error: 163 *lenp = 0; /* ??? */ 164 return (NULL); /* ??? */ 165 } 166