1 /* $NetBSD: fgetstr.c,v 1.4 2006/11/24 19:46:58 christos 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 1.4 2006/11/24 19:46:58 christos 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 /* 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 int 61 __slbexpand(fp, newsize) 62 FILE *fp; 63 size_t newsize; 64 { 65 void *p; 66 67 #ifdef notdef 68 ++newsize; 69 #endif 70 _DIAGASSERT(fp != NULL); 71 72 if (fp->_lb._size >= newsize) 73 return (0); 74 if ((p = realloc(fp->_lb._base, newsize)) == NULL) 75 return (-1); 76 fp->_lb._base = p; 77 fp->_lb._size = newsize; 78 return (0); 79 } 80 81 /* 82 * Get an input line. The returned pointer often (but not always) 83 * points into a stdio buffer. Fgetline does not alter the text of 84 * the returned line (which is thus not a C string because it will 85 * not necessarily end with '\0'), but does allow callers to modify 86 * it if they wish. Thus, we set __SMOD in case the caller does. 87 */ 88 char * 89 __fgetstr(fp, lenp, sep) 90 FILE *fp; 91 size_t *lenp; 92 int sep; 93 { 94 unsigned char *p; 95 size_t len; 96 size_t off; 97 98 _DIAGASSERT(fp != NULL); 99 _DIAGASSERT(lenp != NULL); 100 101 /* make sure there is input */ 102 if (fp->_r <= 0 && __srefill(fp)) { 103 *lenp = 0; 104 return (NULL); 105 } 106 107 /* look for a newline in the input */ 108 if ((p = memchr((void *)fp->_p, sep, (size_t)fp->_r)) != NULL) { 109 char *ret; 110 111 /* 112 * Found one. Flag buffer as modified to keep fseek from 113 * `optimising' a backward seek, in case the user stomps on 114 * the text. 115 */ 116 p++; /* advance over it */ 117 ret = (char *)fp->_p; 118 *lenp = len = p - fp->_p; 119 fp->_flags |= __SMOD; 120 fp->_r -= len; 121 fp->_p = p; 122 return (ret); 123 } 124 125 /* 126 * We have to copy the current buffered data to the line buffer. 127 * As a bonus, though, we can leave off the __SMOD. 128 * 129 * OPTIMISTIC is length that we (optimistically) expect will 130 * accommodate the `rest' of the string, on each trip through the 131 * loop below. 132 */ 133 #define OPTIMISTIC 80 134 135 for (len = fp->_r, off = 0;; len += fp->_r) { 136 size_t diff; 137 138 /* 139 * Make sure there is room for more bytes. Copy data from 140 * file buffer to line buffer, refill file and look for 141 * newline. The loop stops only when we find a newline. 142 */ 143 if (__slbexpand(fp, len + OPTIMISTIC)) 144 goto error; 145 (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_p, 146 len - off); 147 off = len; 148 if (__srefill(fp)) 149 break; /* EOF or error: return partial line */ 150 if ((p = memchr((void *)fp->_p, sep, (size_t)fp->_r)) == NULL) 151 continue; 152 153 /* got it: finish up the line (like code above) */ 154 p++; 155 diff = p - fp->_p; 156 len += diff; 157 if (__slbexpand(fp, len)) 158 goto error; 159 (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_p, 160 diff); 161 fp->_r -= diff; 162 fp->_p = p; 163 break; 164 } 165 *lenp = len; 166 #ifdef notdef 167 fp->_lb._base[len] = 0; 168 #endif 169 return ((char *)fp->_lb._base); 170 171 error: 172 *lenp = 0; /* ??? */ 173 return (NULL); /* ??? */ 174 } 175