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