1 /* $OpenBSD: fparseln.c,v 1.4 2002/06/09 22:18:43 fgsch Exp $ */ 2 /* $NetBSD: fparseln.c,v 1.7 1999/07/02 15:49:12 simonb Exp $ */ 3 4 /* 5 * Copyright (c) 1997 Christos Zoulas. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by Christos Zoulas. 18 * 4. The name of the author may not be used to endorse or promote products 19 * derived from this software without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 #if defined(LIBC_SCCS) && !defined(lint) 34 static const char rcsid[] = "$OpenBSD: fparseln.c,v 1.4 2002/06/09 22:18:43 fgsch Exp $"; 35 #endif /* LIBC_SCCS and not lint */ 36 37 #include <sys/cdefs.h> 38 39 #include <stdio.h> 40 #include <string.h> 41 #include <stdlib.h> 42 43 #include "util.h" 44 45 static int isescaped(const char *, const char *, int); 46 47 /* isescaped(): 48 * Return true if the character in *p that belongs to a string 49 * that starts in *sp, is escaped by the escape character esc. 50 */ 51 static int 52 isescaped(sp, p, esc) 53 const char *sp, *p; 54 int esc; 55 { 56 const char *cp; 57 size_t ne; 58 59 /* No escape character */ 60 if (esc == '\0') 61 return 1; 62 63 /* Count the number of escape characters that precede ours */ 64 for (ne = 0, cp = p; --cp >= sp && *cp == esc; ne++) 65 continue; 66 67 /* Return true if odd number of escape characters */ 68 return (ne & 1) != 0; 69 } 70 71 72 /* fparseln(): 73 * Read a line from a file parsing continuations ending in \ 74 * and eliminating trailing newlines, or comments starting with 75 * the comment char. 76 */ 77 char * 78 fparseln(fp, size, lineno, str, flags) 79 FILE *fp; 80 size_t *size; 81 size_t *lineno; 82 const char str[3]; 83 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 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 escape */ 139 cnt = 1; 140 } 141 } 142 143 if (s == 0 && buf != NULL) 144 continue; 145 146 if ((cp = realloc(buf, len + s + 1)) == NULL) { 147 free(buf); 148 return NULL; 149 } 150 buf = cp; 151 152 (void) memcpy(buf + len, ptr, s); 153 len += s; 154 buf[len] = '\0'; 155 } 156 157 if ((flags & FPARSELN_UNESCALL) != 0 && esc && buf != NULL && 158 strchr(buf, esc) != NULL) { 159 ptr = cp = buf; 160 while (cp[0] != '\0') { 161 int skipesc; 162 163 while (cp[0] != '\0' && cp[0] != esc) 164 *ptr++ = *cp++; 165 if (cp[0] == '\0' || cp[1] == '\0') 166 break; 167 168 skipesc = 0; 169 if (cp[1] == com) 170 skipesc += (flags & FPARSELN_UNESCCOMM); 171 if (cp[1] == con) 172 skipesc += (flags & FPARSELN_UNESCCONT); 173 if (cp[1] == esc) 174 skipesc += (flags & FPARSELN_UNESCESC); 175 if (cp[1] != com && cp[1] != con && cp[1] != esc) 176 skipesc = (flags & FPARSELN_UNESCREST); 177 178 if (skipesc) 179 cp++; 180 else 181 *ptr++ = *cp++; 182 *ptr++ = *cp++; 183 } 184 *ptr = '\0'; 185 len = strlen(buf); 186 } 187 188 if (size) 189 *size = len; 190 return buf; 191 } 192 193 #ifdef TEST 194 195 int main(int, char **); 196 197 int 198 main(argc, argv) 199 int argc; 200 char **argv; 201 { 202 char *ptr; 203 size_t size, line; 204 205 line = 0; 206 while ((ptr = fparseln(stdin, &size, &line, NULL, 207 FPARSELN_UNESCALL)) != NULL) 208 printf("line %d (%d) |%s|\n", line, size, ptr); 209 return 0; 210 } 211 212 /* 213 214 # This is a test 215 line 1 216 line 2 \ 217 line 3 # Comment 218 line 4 \# Not comment \\\\ 219 220 # And a comment \ 221 line 5 \\\ 222 line 6 223 224 */ 225 226 #endif /* TEST */ 227