StdLib/LibC/Stdio/fparseln.c

   1 /*  $NetBSD: fparseln.c,v 1.5 2004/06/20 22:20:15 jmc 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 #include  <LibConfig.h>
  32 #include <sys/EfiCdefs.h>
  33 #if defined(LIBC_SCCS) && !defined(lint)
  34 __RCSID("$NetBSD: fparseln.c,v 1.5 2004/06/20 22:20:15 jmc Exp $");
  35 #endif /* LIBC_SCCS and not lint */
  36
  37 #include "namespace.h"
  38
  39 #include <assert.h>
  40 #include <errno.h>
  41 #include <stdio.h>
  42 #include <string.h>
  43 #include <stdlib.h>
  44
  45 #ifdef __weak_alias
  46 __weak_alias(fparseln,_fparseln)
  47 #endif
  48
  49 #if ! HAVE_FPARSELN
  50
  51 #ifndef HAVE_NBTOOL_CONFIG_H
  52 #include "reentrant.h"
  53 #include "local.h"
  54 #else
  55 #define FLOCKFILE(fp)
  56 #define FUNLOCKFILE(fp)
  57 #endif
  58
  59 #if defined(_REENTRANT) && !HAVE_NBTOOL_CONFIG_H
  60 #define __fgetln(f, l) __fgetstr(f, l, '\n')
  61 #else
  62 #define __fgetln(f, l) fgetln(f, l)
  63 #endif
  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(const char *sp, const char *p, int esc)
  73 {
  74   const char     *cp;
  75   size_t    ne;
  76
  77   _DIAGASSERT(sp != NULL);
  78   _DIAGASSERT(p != NULL);
  79
  80   /* No escape character */
  81   if (esc == '\0')
  82     return 1;
  83
  84   /* Count the number of escape characters that precede ours */
  85   for (ne = 0, cp = p; --cp >= sp && *cp == esc; ne++)
  86     continue;
  87
  88   /* Return true if odd number of escape characters */
  89   return (ne & 1) != 0;
  90 }
  91
  92
  93 /* fparseln():
  94  *  Read a line from a file parsing continuations ending in \
  95  *  and eliminating trailing newlines, or comments starting with
  96  *  the comment char.
  97  */
  98 char *
  99 fparseln(FILE *fp, size_t *size, size_t *lineno, const char str[3], int flags)
 100 {
 101   static const char dstr[3] = { '\\', '\\', '#' };
 102
 103   size_t  s, len;
 104   char   *buf;
 105   char   *ptr, *cp;
 106   int cnt;
 107   char  esc, con, nl, com;
 108
 109   _DIAGASSERT(fp != NULL);
 110
 111   len = 0;
 112   buf = NULL;
 113   cnt = 1;
 114
 115   if (str == NULL)
 116     str = dstr;
 117
 118   esc = str[0];
 119   con = str[1];
 120   com = str[2];
 121   /*
 122    * XXX: it would be cool to be able to specify the newline character,
 123    * but unfortunately, fgetln does not let us
 124    */
 125   nl  = '\n';
 126
 127   FLOCKFILE(fp);
 128
 129   while (cnt) {
 130     cnt = 0;
 131
 132     if (lineno)
 133       (*lineno)++;
 134
 135     if ((ptr = __fgetln(fp, &s)) == NULL)
 136       break;
 137
 138     if (s && com) {   /* Check and eliminate comments */
 139       for (cp = ptr; cp < ptr + s; cp++)
 140         if (*cp == com && !isescaped(ptr, cp, esc)) {
 141           s = cp - ptr;
 142           cnt = s == 0 && buf == NULL;
 143           break;
 144         }
 145     }
 146
 147     if (s && nl) {    /* Check and eliminate newlines */
 148       cp = &ptr[s - 1];
 149
 150       if (*cp == nl)
 151         s--;  /* forget newline */
 152     }
 153
 154     if (s && con) {   /* Check and eliminate continuations */
 155       cp = &ptr[s - 1];
 156
 157       if (*cp == con && !isescaped(ptr, cp, esc)) {
 158         s--;  /* forget escape */
 159         cnt = 1;
 160       }
 161     }
 162
 163     if (s == 0 && buf != NULL)
 164       continue;
 165
 166     if ((cp = realloc(buf, len + s + 1)) == NULL) {
 167       FUNLOCKFILE(fp);
 168       free(buf);
 169       return NULL;
 170     }
 171     buf = cp;
 172
 173     (void) memcpy(buf + len, ptr, s);
 174     len += s;
 175     buf[len] = '\0';
 176   }
 177
 178   FUNLOCKFILE(fp);
 179
 180   if ((flags & FPARSELN_UNESCALL) != 0 && esc && buf != NULL &&
 181       strchr(buf, esc) != NULL) {
 182     ptr = cp = buf;
 183     while (cp[0] != '\0') {
 184       int skipesc;
 185
 186       while (cp[0] != '\0' && cp[0] != esc)
 187         *ptr++ = *cp++;
 188       if (cp[0] == '\0' || cp[1] == '\0')
 189         break;
 190
 191       skipesc = 0;
 192       if (cp[1] == com)
 193         skipesc += (flags & FPARSELN_UNESCCOMM);
 194       if (cp[1] == con)
 195         skipesc += (flags & FPARSELN_UNESCCONT);
 196       if (cp[1] == esc)
 197         skipesc += (flags & FPARSELN_UNESCESC);
 198       if (cp[1] != com && cp[1] != con && cp[1] != esc)
 199         skipesc = (flags & FPARSELN_UNESCREST);
 200
 201       if (skipesc)
 202         cp++;
 203       else
 204         *ptr++ = *cp++;
 205       *ptr++ = *cp++;
 206     }
 207     *ptr = '\0';
 208     len = strlen(buf);
 209   }
 210
 211   if (size)
 212     *size = len;
 213   return buf;
 214 }
 215
 216 #ifdef TEST
 217
 218 int main(int, char **);
 219
 220 int
 221 main(int argc, char **argv)
 222 {
 223   char   *ptr;
 224   size_t  size, line;
 225
 226   line = 0;
 227   while ((ptr = fparseln(stdin, &size, &line, NULL,
 228       FPARSELN_UNESCALL)) != NULL)
 229     printf("line %d (%d) |%s|\n", line, size, ptr);
 230   return 0;
 231 }
 232
 233 /*
 234
 235 # This is a test
 236 line 1
 237 line 2 \
 238 line 3 # Comment
 239 line 4 \# Not comment \\\\
 240
 241 # And a comment \
 242 line 5 \\\
 243 line 6
 244
 245 */
 246
 247 #endif /* TEST */
 248 #endif  /* ! HAVE_FPARSELN */