1 /* $NetBSD: fgetstr.c,v 1.2 2004/05/10 16:47:11 drochner Exp $ */ 2 3 /*- 4 * Copyright (c) 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Chris Torek. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include <sys/cdefs.h> 36 #if defined(LIBC_SCCS) && !defined(lint) 37 #if 0 38 static char sccsid[] = "@(#)fgetline.c 8.1 (Berkeley) 6/4/93"; 39 #else 40 __RCSID("$NetBSD: fgetstr.c,v 1.2 2004/05/10 16:47:11 drochner Exp $"); 41 #endif 42 #endif /* LIBC_SCCS and not lint */ 43 44 #include "namespace.h" 45 46 #include <assert.h> 47 #include <stdio.h> 48 #include <stdlib.h> 49 #include <string.h> 50 #include "reentrant.h" 51 #include "local.h" 52 53 int __slbexpand __P((FILE *, size_t)); 54 55 /* 56 * Expand the line buffer. Return -1 on error. 57 #ifdef notdef 58 * The `new size' does not account for a terminating '\0', 59 * so we add 1 here. 60 #endif 61 */ 62 int 63 __slbexpand(fp, newsize) 64 FILE *fp; 65 size_t newsize; 66 { 67 void *p; 68 69 #ifdef notdef 70 ++newsize; 71 #endif 72 _DIAGASSERT(fp != NULL); 73 74 if (fp->_lb._size >= newsize) 75 return (0); 76 if ((p = realloc(fp->_lb._base, newsize)) == NULL) 77 return (-1); 78 fp->_lb._base = p; 79 fp->_lb._size = newsize; 80 return (0); 81 } 82 83 /* 84 * Get an input line. The returned pointer often (but not always) 85 * points into a stdio buffer. Fgetline does not alter the text of 86 * the returned line (which is thus not a C string because it will 87 * not necessarily end with '\0'), but does allow callers to modify 88 * it if they wish. Thus, we set __SMOD in case the caller does. 89 */ 90 char * 91 __fgetstr(fp, lenp, sep) 92 FILE *fp; 93 size_t *lenp; 94 int sep; 95 { 96 unsigned char *p; 97 size_t len; 98 size_t off; 99 100 _DIAGASSERT(fp != NULL); 101 _DIAGASSERT(lenp != NULL); 102 103 /* make sure there is input */ 104 if (fp->_r <= 0 && __srefill(fp)) { 105 *lenp = 0; 106 return (NULL); 107 } 108 109 /* look for a newline in the input */ 110 if ((p = memchr((void *)fp->_p, sep, (size_t)fp->_r)) != NULL) { 111 char *ret; 112 113 /* 114 * Found one. Flag buffer as modified to keep fseek from 115 * `optimising' a backward seek, in case the user stomps on 116 * the text. 117 */ 118 p++; /* advance over it */ 119 ret = (char *)fp->_p; 120 *lenp = len = p - fp->_p; 121 fp->_flags |= __SMOD; 122 fp->_r -= len; 123 fp->_p = p; 124 return (ret); 125 } 126 127 /* 128 * We have to copy the current buffered data to the line buffer. 129 * As a bonus, though, we can leave off the __SMOD. 130 * 131 * OPTIMISTIC is length that we (optimistically) expect will 132 * accomodate the `rest' of the string, on each trip through the 133 * loop below. 134 */ 135 #define OPTIMISTIC 80 136 137 for (len = fp->_r, off = 0;; len += fp->_r) { 138 size_t diff; 139 140 /* 141 * Make sure there is room for more bytes. Copy data from 142 * file buffer to line buffer, refill file and look for 143 * newline. The loop stops only when we find a newline. 144 */ 145 if (__slbexpand(fp, len + OPTIMISTIC)) 146 goto error; 147 (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_p, 148 len - off); 149 off = len; 150 if (__srefill(fp)) 151 break; /* EOF or error: return partial line */ 152 if ((p = memchr((void *)fp->_p, sep, (size_t)fp->_r)) == NULL) 153 continue; 154 155 /* got it: finish up the line (like code above) */ 156 p++; 157 diff = p - fp->_p; 158 len += diff; 159 if (__slbexpand(fp, len)) 160 goto error; 161 (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_p, 162 diff); 163 fp->_r -= diff; 164 fp->_p = p; 165 break; 166 } 167 *lenp = len; 168 #ifdef notdef 169 fp->_lb._base[len] = 0; 170 #endif 171 return ((char *)fp->_lb._base); 172 173 error: 174 *lenp = 0; /* ??? */ 175 return (NULL); /* ??? */ 176 } 177