1 /* $NetBSD: fparseln.c,v 1.7 2007/03/08 19:57:53 drochner Exp $ */ 2 3 /* 4 * Copyright (c) 1997 Christos Zoulas. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. All advertising materials mentioning features or use of this software 15 * must display the following acknowledgement: 16 * This product includes software developed by Christos Zoulas. 17 * 4. The name of the author may not be used to endorse or promote products 18 * derived from this software without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 21 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 22 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 23 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 24 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 25 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 29 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 #if defined(LIBC_SCCS) && !defined(lint) 34 __RCSID("$NetBSD: fparseln.c,v 1.7 2007/03/08 19:57:53 drochner Exp $"); 35 #endif /* LIBC_SCCS and not lint */ 36 37 #include "namespace.h" 38 39 #include <assert.h> 40 #include <errno.h> 41 #include <stdio.h> 42 #include <string.h> 43 #include <stdlib.h> 44 45 #ifdef __weak_alias 46 __weak_alias(fparseln,_fparseln) 47 #endif 48 49 #if ! HAVE_FPARSELN 50 51 #ifndef HAVE_NBTOOL_CONFIG_H 52 #include "reentrant.h" 53 #include "local.h" 54 #else 55 #define FLOCKFILE(fp) 56 #define FUNLOCKFILE(fp) 57 #endif 58 59 #if defined(_REENTRANT) && !HAVE_NBTOOL_CONFIG_H 60 #define __fgetln(f, l) __fgetstr(f, l, '\n') 61 #else 62 #define __fgetln(f, l) fgetln(f, l) 63 #endif 64 65 static int isescaped(const char *, const char *, int); 66 67 /* isescaped(): 68 * Return true if the character in *p that belongs to a string 69 * that starts in *sp, is escaped by the escape character esc. 70 */ 71 static int 72 isescaped(const char *sp, const char *p, int esc) 73 { 74 const char *cp; 75 size_t ne; 76 77 _DIAGASSERT(sp != NULL); 78 _DIAGASSERT(p != NULL); 79 80 /* No escape character */ 81 if (esc == '\0') 82 return 0; 83 84 /* Count the number of escape characters that precede ours */ 85 for (ne = 0, cp = p; --cp >= sp && *cp == esc; ne++) 86 continue; 87 88 /* Return true if odd number of escape characters */ 89 return (ne & 1) != 0; 90 } 91 92 93 /* fparseln(): 94 * Read a line from a file parsing continuations ending in \ 95 * and eliminating trailing newlines, or comments starting with 96 * the comment char. 97 */ 98 char * 99 fparseln(FILE *fp, size_t *size, size_t *lineno, const char str[3], int flags) 100 { 101 static const char dstr[3] = { '\\', '\\', '#' }; 102 103 size_t s, len; 104 char *buf; 105 char *ptr, *cp; 106 int cnt; 107 char esc, con, nl, com; 108 109 _DIAGASSERT(fp != NULL); 110 111 len = 0; 112 buf = NULL; 113 cnt = 1; 114 115 if (str == NULL) 116 str = dstr; 117 118 esc = str[0]; 119 con = str[1]; 120 com = str[2]; 121 /* 122 * XXX: it would be cool to be able to specify the newline character, 123 * but unfortunately, fgetln does not let us 124 */ 125 nl = '\n'; 126 127 FLOCKFILE(fp); 128 129 while (cnt) { 130 cnt = 0; 131 132 if (lineno) 133 (*lineno)++; 134 135 if ((ptr = __fgetln(fp, &s)) == NULL) 136 break; 137 138 if (s && com) { /* Check and eliminate comments */ 139 for (cp = ptr; cp < ptr + s; cp++) 140 if (*cp == com && !isescaped(ptr, cp, esc)) { 141 s = cp - ptr; 142 cnt = s == 0 && buf == NULL; 143 break; 144 } 145 } 146 147 if (s && nl) { /* Check and eliminate newlines */ 148 cp = &ptr[s - 1]; 149 150 if (*cp == nl) 151 s--; /* forget newline */ 152 } 153 154 if (s && con) { /* Check and eliminate continuations */ 155 cp = &ptr[s - 1]; 156 157 if (*cp == con && !isescaped(ptr, cp, esc)) { 158 s--; /* forget continuation char */ 159 cnt = 1; 160 } 161 } 162 163 if (s == 0) { 164 /* 165 * nothing to add, skip realloc except in case 166 * we need a minimal buf to return an empty line 167 */ 168 if (cnt || buf != NULL) 169 continue; 170 } 171 172 if ((cp = realloc(buf, len + s + 1)) == NULL) { 173 FUNLOCKFILE(fp); 174 free(buf); 175 return NULL; 176 } 177 buf = cp; 178 179 (void) memcpy(buf + len, ptr, s); 180 len += s; 181 buf[len] = '\0'; 182 } 183 184 FUNLOCKFILE(fp); 185 186 if ((flags & FPARSELN_UNESCALL) != 0 && esc && buf != NULL && 187 strchr(buf, esc) != NULL) { 188 ptr = cp = buf; 189 while (cp[0] != '\0') { 190 int skipesc; 191 192 while (cp[0] != '\0' && cp[0] != esc) 193 *ptr++ = *cp++; 194 if (cp[0] == '\0' || cp[1] == '\0') 195 break; 196 197 skipesc = 0; 198 if (cp[1] == com) 199 skipesc += (flags & FPARSELN_UNESCCOMM); 200 if (cp[1] == con) 201 skipesc += (flags & FPARSELN_UNESCCONT); 202 if (cp[1] == esc) 203 skipesc += (flags & FPARSELN_UNESCESC); 204 if (cp[1] != com && cp[1] != con && cp[1] != esc) 205 skipesc = (flags & FPARSELN_UNESCREST); 206 207 if (skipesc) 208 cp++; 209 else 210 *ptr++ = *cp++; 211 *ptr++ = *cp++; 212 } 213 *ptr = '\0'; 214 len = strlen(buf); 215 } 216 217 if (size) 218 *size = len; 219 return buf; 220 } 221 222 #ifdef TEST 223 224 int main(int, char **); 225 226 int 227 main(int argc, char **argv) 228 { 229 char *ptr; 230 size_t size, line; 231 232 line = 0; 233 while ((ptr = fparseln(stdin, &size, &line, NULL, 234 FPARSELN_UNESCALL)) != NULL) 235 printf("line %d (%d) |%s|\n", line, size, ptr); 236 return 0; 237 } 238 239 /* 240 241 # This is a test 242 line 1 243 line 2 \ 244 line 3 # Comment 245 line 4 \# Not comment \\\\ 246 247 # And a comment \ 248 line 5 \\\ 249 line 6 250 251 */ 252 253 #endif /* TEST */ 254 #endif /* ! HAVE_FPARSELN */ 255