util/fparseln.c

   1 /*
   2  * Copyright (c) 2003 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 /*      $NetBSD: fparseln.c,v 1.9 1999/09/20 04:48:06 lukem Exp $       */
  24
  25 /*
  26  * Copyright (c) 1997 Christos Zoulas.  All rights reserved.
  27  *
  28  * Redistribution and use in source and binary forms, with or without
  29  * modification, are permitted provided that the following conditions
  30  * are met:
  31  * 1. Redistributions of source code must retain the above copyright
  32  *    notice, this list of conditions and the following disclaimer.
  33  * 2. Redistributions in binary form must reproduce the above copyright
  34  *    notice, this list of conditions and the following disclaimer in the
  35  *    documentation and/or other materials provided with the distribution.
  36  * 3. All advertising materials mentioning features or use of this software
  37  *    must display the following acknowledgement:
  38  *      This product includes software developed by Christos Zoulas.
  39  * 4. The name of the author may not be used to endorse or promote products
  40  *    derived from this software without specific prior written permission.
  41  *
  42  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  43  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  44  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  45  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  46  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  47  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  48  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  49  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  50  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  51  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  52  */
  53
  54 #include <sys/cdefs.h>
  55 __FBSDID("$FreeBSD: src/lib/libutil/fparseln.c,v 1.5 2002/03/21 23:52:49 obrien Exp $");
  56
  57 #include <sys/types.h>
  58 #include <assert.h>
  59 #include <errno.h>
  60 #include <stdio.h>
  61 #include <string.h>
  62 #include <stdlib.h>
  63 #include <util.h>
  64
  65 static int isescaped(const char *, const char *, int);
  66
  67 /* isescaped():
  68  *      Return true if the character in *p that belongs to a string
  69  *      that starts in *sp, is escaped by the escape character esc.
  70  */
  71 static int
  72 isescaped(sp, p, esc)
  73         const char *sp, *p;
  74         int esc;
  75 {
  76         const char     *cp;
  77         size_t          ne;
  78
  79 #if 0
  80         _DIAGASSERT(sp != NULL);
  81         _DIAGASSERT(p != NULL);
  82 #endif
  83
  84         /* No escape character */
  85         if (esc == '\0')
  86                 return 1;
  87
  88         /* Count the number of escape characters that precede ours */
  89         for (ne = 0, cp = p; --cp >= sp && *cp == esc; ne++)
  90                 continue;
  91
  92         /* Return true if odd number of escape characters */
  93         return (ne & 1) != 0;
  94 }
  95
  96
  97 /* fparseln():
  98  *      Read a line from a file parsing continuations ending in \
  99  *      and eliminating trailing newlines, or comments starting with
 100  *      the comment char.
 101  */
 102 char *
 103 fparseln(fp, size, lineno, str, flags)
 104         FILE            *fp;
 105         size_t          *size;
 106         size_t          *lineno;
 107         const char       str[3];
 108         int              flags;
 109 {
 110         static const char dstr[3] = { '\\', '\\', '#' };
 111
 112         size_t  s, len;
 113         char   *buf;
 114         char   *ptr, *cp;
 115         int     cnt;
 116         char    esc, con, nl, com;
 117
 118 #if 0
 119         _DIAGASSERT(fp != NULL);
 120 #endif
 121
 122         len = 0;
 123         buf = NULL;
 124         cnt = 1;
 125
 126         if (str == NULL)
 127                 str = dstr;
 128
 129         esc = str[0];
 130         con = str[1];
 131         com = str[2];
 132         /*
 133          * XXX: it would be cool to be able to specify the newline character,
 134          * but unfortunately, fgetln does not let us
 135          */
 136         nl  = '\n';
 137
 138         while (cnt) {
 139                 cnt = 0;
 140
 141                 if (lineno)
 142                         (*lineno)++;
 143
 144                 if ((ptr = fgetln(fp, &s)) == NULL)
 145                         break;
 146
 147                 if (s && com) {         /* Check and eliminate comments */
 148                         for (cp = ptr; cp < ptr + s; cp++)
 149                                 if (*cp == com && !isescaped(ptr, cp, esc)) {
 150                                         s = cp - ptr;
 151                                         cnt = s == 0 && buf == NULL;
 152                                         break;
 153                                 }
 154                 }
 155
 156                 if (s && nl) {          /* Check and eliminate newlines */
 157                         cp = &ptr[s - 1];
 158
 159                         if (*cp == nl)
 160                                 s--;    /* forget newline */
 161                 }
 162
 163                 if (s && con) {         /* Check and eliminate continuations */
 164                         cp = &ptr[s - 1];
 165
 166                         if (*cp == con && !isescaped(ptr, cp, esc)) {
 167                                 s--;    /* forget escape */
 168                                 cnt = 1;
 169                         }
 170                 }
 171
 172                 if (s == 0 && buf != NULL)
 173                         continue;
 174
 175                 if ((cp = realloc(buf, len + s + 1)) == NULL) {
 176                         free(buf);
 177                         return NULL;
 178                 }
 179                 buf = cp;
 180
 181                 (void) memcpy(buf + len, ptr, s);
 182                 len += s;
 183                 buf[len] = '\0';
 184         }
 185
 186         if ((flags & FPARSELN_UNESCALL) != 0 && esc && buf != NULL &&
 187             strchr(buf, esc) != NULL) {
 188                 ptr = cp = buf;
 189                 while (cp[0] != '\0') {
 190                         int skipesc;
 191
 192                         while (cp[0] != '\0' && cp[0] != esc)
 193                                 *ptr++ = *cp++;
 194                         if (cp[0] == '\0' || cp[1] == '\0')
 195                                 break;
 196
 197                         skipesc = 0;
 198                         if (cp[1] == com)
 199                                 skipesc += (flags & FPARSELN_UNESCCOMM);
 200                         if (cp[1] == con)
 201                                 skipesc += (flags & FPARSELN_UNESCCONT);
 202                         if (cp[1] == esc)
 203                                 skipesc += (flags & FPARSELN_UNESCESC);
 204                         if (cp[1] != com && cp[1] != con && cp[1] != esc)
 205                                 skipesc = (flags & FPARSELN_UNESCREST);
 206
 207                         if (skipesc)
 208                                 cp++;
 209                         else
 210                                 *ptr++ = *cp++;
 211                         *ptr++ = *cp++;
 212                 }
 213                 *ptr = '\0';
 214                 len = strlen(buf);
 215         }
 216
 217         if (size)
 218                 *size = len;
 219         return buf;
 220 }
 221
 222 #ifdef TEST
 223
 224 int main(int, char **);
 225
 226 int
 227 main(argc, argv)
 228         int argc;
 229         char **argv;
 230 {
 231         char   *ptr;
 232         size_t  size, line;
 233
 234         line = 0;
 235         while ((ptr = fparseln(stdin, &size, &line, NULL,
 236             FPARSELN_UNESCALL)) != NULL)
 237                 printf("line %d (%d) |%s|\n", line, size, ptr);
 238         return 0;
 239 }
 240
 241 /*
 242
 243 # This is a test
 244 line 1
 245 line 2 \
 246 line 3 # Comment
 247 line 4 \# Not comment \\\\
 248
 249 # And a comment \
 250 line 5 \\\
 251 line 6
 252
 253 */
 254
 255 #endif /* TEST */