1 /* $OpenBSD: fparseln.c,v 1.1 1999/07/20 16:38:56 jakob 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 char rcsid[] = "$OpenBSD: fparseln.c,v 1.1 1999/07/20 16:38:56 jakob 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 #include <util.h> 43 44 static int isescaped __P((const char *, const char *, int)); 45 46 /* isescaped(): 47 * Return true if the character in *p that belongs to a string 48 * that starts in *sp, is escaped by the escape character esc. 49 */ 50 static int 51 isescaped(sp, p, esc) 52 const char *sp, *p; 53 int esc; 54 { 55 const char *cp; 56 size_t ne; 57 58 /* No escape character */ 59 if (esc == '\0') 60 return 1; 61 62 /* Count the number of escape characters that precede ours */ 63 for (ne = 0, cp = p; --cp >= sp && *cp == esc; ne++) 64 continue; 65 66 /* Return true if odd number of escape characters */ 67 return (ne & 1) != 0; 68 } 69 70 71 /* fparseln(): 72 * Read a line from a file parsing continuations ending in \ 73 * and eliminating trailing newlines, or comments starting with 74 * the comment char. 75 */ 76 char * 77 fparseln(fp, size, lineno, str, flags) 78 FILE *fp; 79 size_t *size; 80 size_t *lineno; 81 const char str[3]; 82 int flags; 83 { 84 static const char dstr[3] = { '\\', '\\', '#' }; 85 86 size_t s, len; 87 char *buf; 88 char *ptr, *cp; 89 int cnt; 90 char esc, con, nl, com; 91 92 len = 0; 93 buf = NULL; 94 cnt = 1; 95 96 if (str == NULL) 97 str = dstr; 98 99 esc = str[0]; 100 con = str[1]; 101 com = str[2]; 102 /* 103 * XXX: it would be cool to be able to specify the newline character, 104 * but unfortunately, fgetln does not let us 105 */ 106 nl = '\n'; 107 108 while (cnt) { 109 cnt = 0; 110 111 if (lineno) 112 (*lineno)++; 113 114 if ((ptr = fgetln(fp, &s)) == NULL) 115 break; 116 117 if (s && com) { /* Check and eliminate comments */ 118 for (cp = ptr; cp < ptr + s; cp++) 119 if (*cp == com && !isescaped(ptr, cp, esc)) { 120 s = cp - ptr; 121 cnt = s == 0 && buf == NULL; 122 break; 123 } 124 } 125 126 if (s && nl) { /* Check and eliminate newlines */ 127 cp = &ptr[s - 1]; 128 129 if (*cp == nl) 130 s--; /* forget newline */ 131 } 132 133 if (s && con) { /* Check and eliminate continuations */ 134 cp = &ptr[s - 1]; 135 136 if (*cp == con && !isescaped(ptr, cp, esc)) { 137 s--; /* forget escape */ 138 cnt = 1; 139 } 140 } 141 142 if (s == 0 && buf != NULL) 143 continue; 144 145 if ((cp = realloc(buf, len + s + 1)) == NULL) { 146 free(buf); 147 return NULL; 148 } 149 buf = cp; 150 151 (void) memcpy(buf + len, ptr, s); 152 len += s; 153 buf[len] = '\0'; 154 } 155 156 if ((flags & FPARSELN_UNESCALL) != 0 && esc && buf != NULL && 157 strchr(buf, esc) != NULL) { 158 ptr = cp = buf; 159 while (cp[0] != '\0') { 160 int skipesc; 161 162 while (cp[0] != '\0' && cp[0] != esc) 163 *ptr++ = *cp++; 164 if (cp[0] == '\0' || cp[1] == '\0') 165 break; 166 167 skipesc = 0; 168 if (cp[1] == com) 169 skipesc += (flags & FPARSELN_UNESCCOMM); 170 if (cp[1] == con) 171 skipesc += (flags & FPARSELN_UNESCCONT); 172 if (cp[1] == esc) 173 skipesc += (flags & FPARSELN_UNESCESC); 174 if (cp[1] != com && cp[1] != con && cp[1] != esc) 175 skipesc = (flags & FPARSELN_UNESCREST); 176 177 if (skipesc) 178 cp++; 179 else 180 *ptr++ = *cp++; 181 *ptr++ = *cp++; 182 } 183 *ptr = '\0'; 184 len = strlen(buf); 185 } 186 187 if (size) 188 *size = len; 189 return buf; 190 } 191 192 #ifdef TEST 193 194 int main __P((int, char **)); 195 196 int 197 main(argc, argv) 198 int argc; 199 char **argv; 200 { 201 char *ptr; 202 size_t size, line; 203 204 line = 0; 205 while ((ptr = fparseln(stdin, &size, &line, NULL, 206 FPARSELN_UNESCALL)) != NULL) 207 printf("line %d (%d) |%s|\n", line, size, ptr); 208 return 0; 209 } 210 211 /* 212 213 # This is a test 214 line 1 215 line 2 \ 216 line 3 # Comment 217 line 4 \# Not comment \\\\ 218 219 # And a comment \ 220 line 5 \\\ 221 line 6 222 223 */ 224 225 #endif /* TEST */ 226