libknot: add TXT rdataset getters

Knot.files

@@ -415,6 +415,7 @@ src/libknot/rrtype/rrsig.h
 src/libknot/rrtype/soa.h
 src/libknot/rrtype/tsig.c
 src/libknot/rrtype/tsig.h
+src/libknot/rrtype/txt.h
 src/libknot/tsig-op.c
 src/libknot/tsig-op.h
 src/libknot/tsig.c

src/Makefile.am

@@ -52,6 +52,7 @@ nobase_libknot_la_HEADERS =			\
 	libknot/rrtype/rrsig.h			\
 	libknot/rrtype/soa.h			\
 	libknot/rrtype/tsig.h			\
+	libknot/rrtype/txt.h			\
 	libknot/tsig-op.h			\
 	libknot/tsig.h
 

src/libknot/libknot.h

@@ -45,6 +45,7 @@
 #include "libknot/rrtype/rrsig.h"
 #include "libknot/rrtype/soa.h"
 #include "libknot/rrtype/tsig.h"
+#include "libknot/rrtype/txt.h"
 #include "libknot/tsig-op.h"
 
 /*! @} */

src/libknot/rrtype/txt.h

+/*  Copyright (C) 2015 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "libknot/rdataset.h"
+
+static inline
+size_t knot_txt_count(const knot_rdataset_t *rrs, size_t pos)
+{
+	KNOT_RDATASET_CHECK(rrs, pos, return 0);
+
+	const knot_rdata_t *rdata = knot_rdataset_at(rrs, pos);
+	const uint8_t *start = knot_rdata_data(rdata);
+	const uint8_t *end = start + knot_rdata_rdlen(rdata);
+
+	size_t count = 0;
+
+	for (const uint8_t *p = start; p < end; p += 1 + *p) {
+		count++;
+	}
+
+	return count;
+}
+
+static inline
+const uint8_t *knot_txt_data(const knot_rdataset_t *rrs, size_t pos, size_t index)
+{
+	KNOT_RDATASET_CHECK(rrs, pos, return NULL);
+
+	const knot_rdata_t *rdata = knot_rdataset_at(rrs, pos);
+	const uint8_t *start = knot_rdata_data(rdata);
+	const uint8_t *end = start + knot_rdata_rdlen(rdata);
+
+	const uint8_t *data = start;
+
+	for (size_t i = 0; i < index; i++) {
+		data += 1 + *data;
+		if (data > end) {
+			return NULL;
+		}
+	}
+
+	return data;
+}