1 /* $NetBSD: fparseln.c,v 1.2 2025/02/11 17:48:30 christos 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 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 #ifdef HAVE_CONFIG_H 27 #include "config.h" 28 #endif 29 30 #ifdef HAVE_SYS_CDEFS_H 31 #include <sys/cdefs.h> 32 #endif 33 #if defined(LIBC_SCCS) && !defined(lint) 34 __RCSID("$NetBSD: fparseln.c,v 1.2 2025/02/11 17:48:30 christos Exp $"); 35 #endif /* LIBC_SCCS and not lint */ 36 37 #include <assert.h> 38 #include <errno.h> 39 #include <stdio.h> 40 #include <string.h> 41 #include <stdlib.h> 42 43 #if ! HAVE_FPARSELN || BROKEN_FPARSELN 44 45 #define FLOCKFILE(fp) 46 #define FUNLOCKFILE(fp) 47 48 #if defined(_REENTRANT) && !HAVE_NBTOOL_CONFIG_H 49 #define __fgetln(f, l) __fgetstr(f, l, '\n') 50 #else 51 #define __fgetln(f, l) fgetln(f, l) 52 #endif 53 54 static int isescaped(const char *, const char *, int); 55 56 /* isescaped(): 57 * Return true if the character in *p that belongs to a string 58 * that starts in *sp, is escaped by the escape character esc. 59 */ 60 static int 61 isescaped(const char *sp, const char *p, int esc) 62 { 63 const char *cp; 64 size_t ne; 65 66 /* No escape character */ 67 if (esc == '\0') 68 return 0; 69 70 /* Count the number of escape characters that precede ours */ 71 for (ne = 0, cp = p; --cp >= sp && *cp == esc; ne++) 72 continue; 73 74 /* Return true if odd number of escape characters */ 75 return (ne & 1) != 0; 76 } 77 78 79 /* fparseln(): 80 * Read a line from a file parsing continuations ending in \ 81 * and eliminating trailing newlines, or comments starting with 82 * the comment char. 83 */ 84 char * 85 fparseln(FILE *fp, size_t *size, size_t *lineno, const char str[3], int flags) 86 { 87 static const char dstr[3] = { '\\', '\\', '#' }; 88 89 size_t s, len; 90 char *buf; 91 char *ptr, *cp; 92 int cnt; 93 char esc, con, nl, com; 94 95 len = 0; 96 buf = NULL; 97 cnt = 1; 98 99 if (str == NULL) 100 str = dstr; 101 102 esc = str[0]; 103 con = str[1]; 104 com = str[2]; 105 /* 106 * XXX: it would be cool to be able to specify the newline character, 107 * but unfortunately, fgetln does not let us 108 */ 109 nl = '\n'; 110 111 FLOCKFILE(fp); 112 113 while (cnt) { 114 cnt = 0; 115 116 if (lineno) 117 (*lineno)++; 118 119 if ((ptr = __fgetln(fp, &s)) == NULL) 120 break; 121 122 if (s && com) { /* Check and eliminate comments */ 123 for (cp = ptr; cp < ptr + s; cp++) 124 if (*cp == com && !isescaped(ptr, cp, esc)) { 125 s = cp - ptr; 126 cnt = s == 0 && buf == NULL; 127 break; 128 } 129 } 130 131 if (s && nl) { /* Check and eliminate newlines */ 132 cp = &ptr[s - 1]; 133 134 if (*cp == nl) 135 s--; /* forget newline */ 136 } 137 138 if (s && con) { /* Check and eliminate continuations */ 139 cp = &ptr[s - 1]; 140 141 if (*cp == con && !isescaped(ptr, cp, esc)) { 142 s--; /* forget continuation char */ 143 cnt = 1; 144 } 145 } 146 147 if (s == 0) { 148 /* 149 * nothing to add, skip realloc except in case 150 * we need a minimal buf to return an empty line 151 */ 152 if (cnt || buf != NULL) 153 continue; 154 } 155 156 if ((cp = realloc(buf, len + s + 1)) == NULL) { 157 FUNLOCKFILE(fp); 158 free(buf); 159 return NULL; 160 } 161 buf = cp; 162 163 (void) memcpy(buf + len, ptr, s); 164 len += s; 165 buf[len] = '\0'; 166 } 167 168 FUNLOCKFILE(fp); 169 170 if ((flags & FPARSELN_UNESCALL) != 0 && esc && buf != NULL && 171 strchr(buf, esc) != NULL) { 172 ptr = cp = buf; 173 while (cp[0] != '\0') { 174 int skipesc; 175 176 while (cp[0] != '\0' && cp[0] != esc) 177 *ptr++ = *cp++; 178 if (cp[0] == '\0' || cp[1] == '\0') 179 break; 180 181 skipesc = 0; 182 if (cp[1] == com) 183 skipesc += (flags & FPARSELN_UNESCCOMM); 184 if (cp[1] == con) 185 skipesc += (flags & FPARSELN_UNESCCONT); 186 if (cp[1] == esc) 187 skipesc += (flags & FPARSELN_UNESCESC); 188 if (cp[1] != com && cp[1] != con && cp[1] != esc) 189 skipesc = (flags & FPARSELN_UNESCREST); 190 191 if (skipesc) 192 cp++; 193 else 194 *ptr++ = *cp++; 195 *ptr++ = *cp++; 196 } 197 *ptr = '\0'; 198 len = strlen(buf); 199 } 200 201 if (size) 202 *size = len; 203 return buf; 204 } 205 206 #ifdef TEST 207 208 int main(int, char **); 209 210 int 211 main(int argc, char **argv) 212 { 213 char *ptr; 214 size_t size, line; 215 216 line = 0; 217 while ((ptr = fparseln(stdin, &size, &line, NULL, 218 FPARSELN_UNESCALL)) != NULL) 219 printf("line %d (%d) |%s|\n", line, size, ptr); 220 return 0; 221 } 222 223 /* 224 225 # This is a test 226 line 1 227 line 2 \ 228 line 3 # Comment 229 line 4 \# Not comment \\\\ 230 231 # And a comment \ 232 line 5 \\\ 233 line 6 234 235 */ 236 237 #endif /* TEST */ 238 #endif /* ! HAVE_FPARSELN || BROKEN_FPARSELN */ 239