Add new fparseln() function

Taken from NetBSD.

[guillem@hadrons.org:
 - Import from NetBSD instead of FreeBSD to get a 3-clause BSD license,
   instead of a 4-clause one.
 - Define compatibility macros.
 - Change library from libc to libbsd and header in man page.
 - Add copyright information to COPYING.
 - Add symbol to map file. ]

Signed-off-by: Guillem Jover <guillem@hadrons.org>

src/Makefile.am

@@ -45,6 +45,7 @@ libbsd_la_SOURCES = \
 	fgetln.c \
 	flopen.c \
 	fmtcheck.c \
+	fparseln.c \
 	fpurge.c \
 	getpeereid.c \
 	hash/md5.c \

src/fparseln.c

@@ -0,0 +1,230 @@
+/*	$NetBSD: fparseln.c,v 1.10 2009/10/21 01:07:45 snj 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.
+ *
+ * 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 <sys/cdefs.h>
+#if defined(LIBC_SCCS) && !defined(lint)
+__RCSID("$NetBSD: fparseln.c,v 1.10 2009/10/21 01:07:45 snj Exp $");
+#endif /* LIBC_SCCS and not lint */
+
+#include <assert.h>
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+#define FLOCKFILE(fp)
+#define FUNLOCKFILE(fp)
+#define _DIAGASSERT(t)
+
+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;
+
+	_DIAGASSERT(sp != NULL);
+	_DIAGASSERT(p != NULL);
+
+	/* No escape character */
+	if (esc == '\0')
+		return 0;
+
+	/* 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] = { '\\', '\\', '#' };
+
+	size_t	s, len;
+	char   *buf;
+	char   *ptr, *cp;
+	int	cnt;
+	char	esc, con, nl, com;
+
+	_DIAGASSERT(fp != NULL);
+
+	len = 0;
+	buf = NULL;
+	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';
+
+	FLOCKFILE(fp);
+
+	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 continuation char */
+				cnt = 1;
+			}
+		}
+
+		if (s == 0) {
+			/*
+			 * nothing to add, skip realloc except in case
+			 * we need a minimal buf to return an empty line
+			 */
+			if (cnt || buf != NULL)
+				continue;
+		}
+
+		if ((cp = realloc(buf, len + s + 1)) == NULL) {
+			FUNLOCKFILE(fp);
+			free(buf);
+			return NULL;
+		}
+		buf = cp;
+
+		(void) memcpy(buf + len, ptr, s);
+		len += s;
+		buf[len] = '\0';
+	}
+
+	FUNLOCKFILE(fp);
+
+	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(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 */

src/libbsd.map

@@ -96,6 +96,8 @@ LIBBSD_0.4 {
 } LIBBSD_0.3;
 
 LIBBSD_0.5 {
+    fparseln;
+
     strnstr;
 
     wcslcat;