1 /* $NetBSD: fparseln.c,v 1.1 2015/01/22 03:48:07 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 #include <sys/cdefs.h> 31 #if defined(LIBC_SCCS) && !defined(lint) 32 __RCSID("$NetBSD: fparseln.c,v 1.1 2015/01/22 03:48:07 christos Exp $"); 33 #endif /* LIBC_SCCS and not lint */ 34 35 #include <assert.h> 36 #include <errno.h> 37 #include <stdio.h> 38 #include <string.h> 39 #include <stdlib.h> 40 41 #if ! HAVE_FPARSELN || BROKEN_FPARSELN 42 43 #define FLOCKFILE(fp) 44 #define FUNLOCKFILE(fp) 45 46 #if defined(_REENTRANT) && !HAVE_NBTOOL_CONFIG_H 47 #define __fgetln(f, l) __fgetstr(f, l, '\n') 48 #else 49 #define __fgetln(f, l) fgetln(f, l) 50 #endif 51 52 static int isescaped(const char *, const char *, int); 53 54 /* isescaped(): 55 * Return true if the character in *p that belongs to a string 56 * that starts in *sp, is escaped by the escape character esc. 57 */ 58 static int 59 isescaped(const char *sp, const char *p, int esc) 60 { 61 const char *cp; 62 size_t ne; 63 64 /* No escape character */ 65 if (esc == '\0') 66 return 0; 67 68 /* Count the number of escape characters that precede ours */ 69 for (ne = 0, cp = p; --cp >= sp && *cp == esc; ne++) 70 continue; 71 72 /* Return true if odd number of escape characters */ 73 return (ne & 1) != 0; 74 } 75 76 77 /* fparseln(): 78 * Read a line from a file parsing continuations ending in \ 79 * and eliminating trailing newlines, or comments starting with 80 * the comment char. 81 */ 82 char * 83 fparseln(FILE *fp, size_t *size, size_t *lineno, const char str[3], int flags) 84 { 85 static const char dstr[3] = { '\\', '\\', '#' }; 86 87 size_t s, len; 88 char *buf; 89 char *ptr, *cp; 90 int cnt; 91 char esc, con, nl, com; 92 93 len = 0; 94 buf = NULL; 95 cnt = 1; 96 97 if (str == NULL) 98 str = dstr; 99 100 esc = str[0]; 101 con = str[1]; 102 com = str[2]; 103 /* 104 * XXX: it would be cool to be able to specify the newline character, 105 * but unfortunately, fgetln does not let us 106 */ 107 nl = '\n'; 108 109 FLOCKFILE(fp); 110 111 while (cnt) { 112 cnt = 0; 113 114 if (lineno) 115 (*lineno)++; 116 117 if ((ptr = __fgetln(fp, &s)) == NULL) 118 break; 119 120 if (s && com) { /* Check and eliminate comments */ 121 for (cp = ptr; cp < ptr + s; cp++) 122 if (*cp == com && !isescaped(ptr, cp, esc)) { 123 s = cp - ptr; 124 cnt = s == 0 && buf == NULL; 125 break; 126 } 127 } 128 129 if (s && nl) { /* Check and eliminate newlines */ 130 cp = &ptr[s - 1]; 131 132 if (*cp == nl) 133 s--; /* forget newline */ 134 } 135 136 if (s && con) { /* Check and eliminate continuations */ 137 cp = &ptr[s - 1]; 138 139 if (*cp == con && !isescaped(ptr, cp, esc)) { 140 s--; /* forget continuation char */ 141 cnt = 1; 142 } 143 } 144 145 if (s == 0) { 146 /* 147 * nothing to add, skip realloc except in case 148 * we need a minimal buf to return an empty line 149 */ 150 if (cnt || buf != NULL) 151 continue; 152 } 153 154 if ((cp = realloc(buf, len + s + 1)) == NULL) { 155 FUNLOCKFILE(fp); 156 free(buf); 157 return NULL; 158 } 159 buf = cp; 160 161 (void) memcpy(buf + len, ptr, s); 162 len += s; 163 buf[len] = '\0'; 164 } 165 166 FUNLOCKFILE(fp); 167 168 if ((flags & FPARSELN_UNESCALL) != 0 && esc && buf != NULL && 169 strchr(buf, esc) != NULL) { 170 ptr = cp = buf; 171 while (cp[0] != '\0') { 172 int skipesc; 173 174 while (cp[0] != '\0' && cp[0] != esc) 175 *ptr++ = *cp++; 176 if (cp[0] == '\0' || cp[1] == '\0') 177 break; 178 179 skipesc = 0; 180 if (cp[1] == com) 181 skipesc += (flags & FPARSELN_UNESCCOMM); 182 if (cp[1] == con) 183 skipesc += (flags & FPARSELN_UNESCCONT); 184 if (cp[1] == esc) 185 skipesc += (flags & FPARSELN_UNESCESC); 186 if (cp[1] != com && cp[1] != con && cp[1] != esc) 187 skipesc = (flags & FPARSELN_UNESCREST); 188 189 if (skipesc) 190 cp++; 191 else 192 *ptr++ = *cp++; 193 *ptr++ = *cp++; 194 } 195 *ptr = '\0'; 196 len = strlen(buf); 197 } 198 199 if (size) 200 *size = len; 201 return buf; 202 } 203 204 #ifdef TEST 205 206 int main(int, char **); 207 208 int 209 main(int argc, char **argv) 210 { 211 char *ptr; 212 size_t size, line; 213 214 line = 0; 215 while ((ptr = fparseln(stdin, &size, &line, NULL, 216 FPARSELN_UNESCALL)) != NULL) 217 printf("line %d (%d) |%s|\n", line, size, ptr); 218 return 0; 219 } 220 221 /* 222 223 # This is a test 224 line 1 225 line 2 \ 226 line 3 # Comment 227 line 4 \# Not comment \\\\ 228 229 # And a comment \ 230 line 5 \\\ 231 line 6 232 233 */ 234 235 #endif /* TEST */ 236 #endif /* ! HAVE_FPARSELN || BROKEN_FPARSELN */ 237