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/* $OpenBSD: fparseln.c,v 1.7 2012/12/05 23:20:06 deraadt Exp $ */
/* $NetBSD: fparseln.c,v 1.7 1999/07/02 15:49:12 simonb Exp $ */
/*
* Copyright (c) 1997 Christos Zoulas. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Christos Zoulas.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "util.h"
static int isescaped(const char *, const char *, int);
/* isescaped():
* Return true if the character in *p that belongs to a string
* that starts in *sp, is escaped by the escape character esc.
*/
static int
isescaped(const char *sp, const char *p, int esc)
{
const char *cp;
size_t ne;
/* No escape character */
if (esc == '\0')
return 1;
/* Count the number of escape characters that precede ours */
for (ne = 0, cp = p; --cp >= sp && *cp == esc; ne++)
continue;
/* Return true if odd number of escape characters */
return (ne & 1) != 0;
}
/* fparseln():
* Read a line from a file parsing continuations ending in \
* and eliminating trailing newlines, or comments starting with
* the comment char.
*/
char *
fparseln(FILE *fp, size_t *size, size_t *lineno, const char str[3],
int flags)
{
static const char dstr[3] = { '\\', '\\', '#' };
char *buf = NULL, *ptr, *cp, esc, con, nl, com;
size_t s, len = 0;
int cnt = 1;
if (str == NULL)
str = dstr;
esc = str[0];
con = str[1];
com = str[2];
/*
* XXX: it would be cool to be able to specify the newline character,
* but unfortunately, fgetln does not let us
*/
nl = '\n';
while (cnt) {
cnt = 0;
if (lineno)
(*lineno)++;
if ((ptr = fgetln(fp, &s)) == NULL)
break;
if (s && com) { /* Check and eliminate comments */
for (cp = ptr; cp < ptr + s; cp++)
if (*cp == com && !isescaped(ptr, cp, esc)) {
s = cp - ptr;
cnt = s == 0 && buf == NULL;
break;
}
}
if (s && nl) { /* Check and eliminate newlines */
cp = &ptr[s - 1];
if (*cp == nl)
s--; /* forget newline */
}
if (s && con) { /* Check and eliminate continuations */
cp = &ptr[s - 1];
if (*cp == con && !isescaped(ptr, cp, esc)) {
s--; /* forget escape */
cnt = 1;
}
}
if (s == 0 && buf != NULL)
continue;
if ((cp = realloc(buf, len + s + 1)) == NULL) {
free(buf);
return NULL;
}
buf = cp;
(void) memcpy(buf + len, ptr, s);
len += s;
buf[len] = '\0';
}
if ((flags & FPARSELN_UNESCALL) != 0 && esc && buf != NULL &&
strchr(buf, esc) != NULL) {
ptr = cp = buf;
while (cp[0] != '\0') {
int skipesc;
while (cp[0] != '\0' && cp[0] != esc)
*ptr++ = *cp++;
if (cp[0] == '\0' || cp[1] == '\0')
break;
skipesc = 0;
if (cp[1] == com)
skipesc += (flags & FPARSELN_UNESCCOMM);
if (cp[1] == con)
skipesc += (flags & FPARSELN_UNESCCONT);
if (cp[1] == esc)
skipesc += (flags & FPARSELN_UNESCESC);
if (cp[1] != com && cp[1] != con && cp[1] != esc)
skipesc = (flags & FPARSELN_UNESCREST);
if (skipesc)
cp++;
else
*ptr++ = *cp++;
*ptr++ = *cp++;
}
*ptr = '\0';
len = strlen(buf);
}
if (size)
*size = len;
return buf;
}
#ifdef TEST
int main(int, char **);
int
main(argc, argv)
int argc;
char **argv;
{
char *ptr;
size_t size, line;
line = 0;
while ((ptr = fparseln(stdin, &size, &line, NULL,
FPARSELN_UNESCALL)) != NULL)
printf("line %d (%d) |%s|\n", line, size, ptr);
return 0;
}
/*
# This is a test
line 1
line 2 \
line 3 # Comment
line 4 \# Not comment \\\\
# And a comment \
line 5 \\\
line 6
*/
#endif /* TEST */
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