fparseln.c
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 __FBSDID("$FreeBSD: src/lib/libutil/fparseln.c,v 1.5 2002/03/21 23:52:49 obrien Exp $"); 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 <util.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(sp, p, esc) 51 const char *sp, *p; 52 int esc; 53 { 54 const char *cp; 55 size_t ne; 56 57 #if 0 58 _DIAGASSERT(sp != NULL); 59 _DIAGASSERT(p != NULL); 60 #endif 61 62 /* No escape character */ 63 if (esc == '\0') 64 return 1; 65 66 /* Count the number of escape characters that precede ours */ 67 for (ne = 0, cp = p; --cp >= sp && *cp == esc; ne++) 68 continue; 69 70 /* Return true if odd number of escape characters */ 71 return (ne & 1) != 0; 72 } 73 74 75 /* fparseln(): 76 * Read a line from a file parsing continuations ending in \ 77 * and eliminating trailing newlines, or comments starting with 78 * the comment char. 79 */ 80 char * 81 fparseln(fp, size, lineno, str, flags) 82 FILE *fp; 83 size_t *size; 84 size_t *lineno; 85 const char str[3]; 86 int flags; 87 { 88 static const char dstr[3] = { '\\', '\\', '#' }; 89 90 size_t s, len; 91 char *buf; 92 char *ptr, *cp; 93 int cnt; 94 char esc, con, nl, com; 95 96 #if 0 97 _DIAGASSERT(fp != NULL); 98 #endif 99 100 len = 0; 101 buf = NULL; 102 cnt = 1; 103 104 if (str == NULL) 105 str = dstr; 106 107 esc = str[0]; 108 con = str[1]; 109 com = str[2]; 110 /* 111 * XXX: it would be cool to be able to specify the newline character, 112 * but unfortunately, fgetln does not let us 113 */ 114 nl = '\n'; 115 116 while (cnt) { 117 cnt = 0; 118 119 if (lineno) 120 (*lineno)++; 121 122 if ((ptr = fgetln(fp, &s)) == NULL) 123 break; 124 125 if (s && com) { /* Check and eliminate comments */ 126 for (cp = ptr; cp < ptr + s; cp++) 127 if (*cp == com && !isescaped(ptr, cp, esc)) { 128 s = cp - ptr; 129 cnt = s == 0 && buf == NULL; 130 break; 131 } 132 } 133 134 if (s && nl) { /* Check and eliminate newlines */ 135 cp = &ptr[s - 1]; 136 137 if (*cp == nl) 138 s--; /* forget newline */ 139 } 140 141 if (s && con) { /* Check and eliminate continuations */ 142 cp = &ptr[s - 1]; 143 144 if (*cp == con && !isescaped(ptr, cp, esc)) { 145 s--; /* forget escape */ 146 cnt = 1; 147 } 148 } 149 150 if (s == 0 && buf != NULL) 151 continue; 152 153 if ((cp = realloc(buf, len + s + 1)) == NULL) { 154 free(buf); 155 return NULL; 156 } 157 buf = cp; 158 159 (void) memcpy(buf + len, ptr, s); 160 len += s; 161 buf[len] = '\0'; 162 } 163 164 if ((flags & FPARSELN_UNESCALL) != 0 && esc && buf != NULL && 165 strchr(buf, esc) != NULL) { 166 ptr = cp = buf; 167 while (cp[0] != '\0') { 168 int skipesc; 169 170 while (cp[0] != '\0' && cp[0] != esc) 171 *ptr++ = *cp++; 172 if (cp[0] == '\0' || cp[1] == '\0') 173 break; 174 175 skipesc = 0; 176 if (cp[1] == com) 177 skipesc += (flags & FPARSELN_UNESCCOMM); 178 if (cp[1] == con) 179 skipesc += (flags & FPARSELN_UNESCCONT); 180 if (cp[1] == esc) 181 skipesc += (flags & FPARSELN_UNESCESC); 182 if (cp[1] != com && cp[1] != con && cp[1] != esc) 183 skipesc = (flags & FPARSELN_UNESCREST); 184 185 if (skipesc) 186 cp++; 187 else 188 *ptr++ = *cp++; 189 *ptr++ = *cp++; 190 } 191 *ptr = '\0'; 192 len = strlen(buf); 193 } 194 195 if (size) 196 *size = len; 197 return buf; 198 } 199 200 #ifdef TEST 201 202 int main(int, char **); 203 204 int 205 main(argc, argv) 206 int argc; 207 char **argv; 208 { 209 char *ptr; 210 size_t size, line; 211 212 line = 0; 213 while ((ptr = fparseln(stdin, &size, &line, NULL, 214 FPARSELN_UNESCALL)) != NULL) 215 printf("line %d (%d) |%s|\n", line, size, ptr); 216 return 0; 217 } 218 219 /* 220 221 # This is a test 222 line 1 223 line 2 \ 224 line 3 # Comment 225 line 4 \# Not comment \\\\ 226 227 # And a comment \ 228 line 5 \\\ 229 line 6 230 231 */ 232 233 #endif /* TEST */