1 /* $NetBSD: fparseln.c,v 1.9 1999/09/20 04:48:06 lukem 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 #if defined(LIBC_SCCS) && !defined(lint) 34 __RCSID("$FreeBSD$"); 35 #endif 36 37 #include <sys/types.h> 38 #include <assert.h> 39 #include <errno.h> 40 #include <stdio.h> 41 #include <string.h> 42 #include <stdlib.h> 43 #include <libutil.h> 44 45 static int isescaped __P((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 #if 0 60 _DIAGASSERT(sp != NULL); 61 _DIAGASSERT(p != NULL); 62 #endif 63 64 /* No escape character */ 65 if (esc == '\0') 66 return 1; 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(fp, size, lineno, str, flags) 84 FILE *fp; 85 size_t *size; 86 size_t *lineno; 87 const char str[3]; 88 int flags; 89 { 90 static const char dstr[3] = { '\\', '\\', '#' }; 91 92 size_t s, len; 93 char *buf; 94 char *ptr, *cp; 95 int cnt; 96 char esc, con, nl, com; 97 98 #if 0 99 _DIAGASSERT(fp != NULL); 100 #endif 101 102 len = 0; 103 buf = NULL; 104 cnt = 1; 105 106 if (str == NULL) 107 str = dstr; 108 109 esc = str[0]; 110 con = str[1]; 111 com = str[2]; 112 /* 113 * XXX: it would be cool to be able to specify the newline character, 114 * but unfortunately, fgetln does not let us 115 */ 116 nl = '\n'; 117 118 while (cnt) { 119 cnt = 0; 120 121 if (lineno) 122 (*lineno)++; 123 124 if ((ptr = fgetln(fp, &s)) == NULL) 125 break; 126 127 if (s && com) { /* Check and eliminate comments */ 128 for (cp = ptr; cp < ptr + s; cp++) 129 if (*cp == com && !isescaped(ptr, cp, esc)) { 130 s = cp - ptr; 131 cnt = s == 0 && buf == NULL; 132 break; 133 } 134 } 135 136 if (s && nl) { /* Check and eliminate newlines */ 137 cp = &ptr[s - 1]; 138 139 if (*cp == nl) 140 s--; /* forget newline */ 141 } 142 143 if (s && con) { /* Check and eliminate continuations */ 144 cp = &ptr[s - 1]; 145 146 if (*cp == con && !isescaped(ptr, cp, esc)) { 147 s--; /* forget escape */ 148 cnt = 1; 149 } 150 } 151 152 if (s == 0 && buf != NULL) 153 continue; 154 155 if ((cp = realloc(buf, len + s + 1)) == NULL) { 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 if ((flags & FPARSELN_UNESCALL) != 0 && esc && buf != NULL && 167 strchr(buf, esc) != NULL) { 168 ptr = cp = buf; 169 while (cp[0] != '\0') { 170 int skipesc; 171 172 while (cp[0] != '\0' && cp[0] != esc) 173 *ptr++ = *cp++; 174 if (cp[0] == '\0' || cp[1] == '\0') 175 break; 176 177 skipesc = 0; 178 if (cp[1] == com) 179 skipesc += (flags & FPARSELN_UNESCCOMM); 180 if (cp[1] == con) 181 skipesc += (flags & FPARSELN_UNESCCONT); 182 if (cp[1] == esc) 183 skipesc += (flags & FPARSELN_UNESCESC); 184 if (cp[1] != com && cp[1] != con && cp[1] != esc) 185 skipesc = (flags & FPARSELN_UNESCREST); 186 187 if (skipesc) 188 cp++; 189 else 190 *ptr++ = *cp++; 191 *ptr++ = *cp++; 192 } 193 *ptr = '\0'; 194 len = strlen(buf); 195 } 196 197 if (size) 198 *size = len; 199 return buf; 200 } 201 202 #ifdef TEST 203 204 int main __P((int, char **)); 205 206 int 207 main(argc, argv) 208 int argc; 209 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