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 /* from: static char sccsid[] = "@(#)fgetline.c 8.1 (Berkeley) 6/4/93"; */ 39 static char *rcsid = "$Id: fgetln.c,v 1.1 1994/01/04 05:13:18 cgd Exp $"; 40 #endif /* LIBC_SCCS and not lint */ 41 42 #include <stdio.h> 43 #include <stdlib.h> 44 #include <string.h> 45 #include "local.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(fp, newsize) 56 FILE *fp; 57 size_t newsize; 58 { 59 void *p; 60 61 #ifdef notdef 62 ++newsize; 63 #endif 64 if (fp->_lb._size >= newsize) 65 return (0); 66 if ((p = realloc(fp->_lb._base, newsize)) == NULL) 67 return (-1); 68 fp->_lb._base = p; 69 fp->_lb._size = newsize; 70 return (0); 71 } 72 73 /* 74 * Get an input line. The returned pointer often (but not always) 75 * points into a stdio buffer. Fgetline does not alter the text of 76 * the returned line (which is thus not a C string because it will 77 * not necessarily end with '\0'), but does allow callers to modify 78 * it if they wish. Thus, we set __SMOD in case the caller does. 79 */ 80 char * 81 fgetln(fp, lenp) 82 register FILE *fp; 83 size_t *lenp; 84 { 85 register unsigned char *p; 86 register size_t len; 87 size_t off; 88 89 /* make sure there is input */ 90 if (fp->_r <= 0 && __srefill(fp)) { 91 *lenp = 0; 92 return (NULL); 93 } 94 95 /* look for a newline in the input */ 96 if ((p = memchr((void *)fp->_p, '\n', fp->_r)) != NULL) { 97 register char *ret; 98 99 /* 100 * Found one. Flag buffer as modified to keep fseek from 101 * `optimising' a backward seek, in case the user stomps on 102 * the text. 103 */ 104 p++; /* advance over it */ 105 ret = (char *)fp->_p; 106 *lenp = len = p - fp->_p; 107 fp->_flags |= __SMOD; 108 fp->_r -= len; 109 fp->_p = p; 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->_r, off = 0;; len += fp->_r) { 124 register 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 (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_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->_p, '\n', fp->_r)) == NULL) 139 continue; 140 141 /* got it: finish up the line (like code above) */ 142 p++; 143 diff = p - fp->_p; 144 len += diff; 145 if (__slbexpand(fp, len)) 146 goto error; 147 (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_p, 148 diff); 149 fp->_r -= diff; 150 fp->_p = p; 151 break; 152 } 153 *lenp = len; 154 #ifdef notdef 155 fp->_lb._base[len] = 0; 156 #endif 157 return ((char *)fp->_lb._base); 158 159 error: 160 *lenp = 0; /* ??? */ 161 return (NULL); /* ??? */ 162 } 163