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+/* Copyright (C) 2018 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/>.
+ */
+/*!
+ * \file
+ *
+ * \brief API for manipulating rdata.
+ *
+ * \addtogroup rr
+ * @{
+ */
+
+#pragma once
+
+#include <assert.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+
+/*!< \brief Maximum rdata length. */
+#define KNOT_RDATA_MAXLEN 65535
+
+/*!
+ * \brief Structure holding single rdata payload.
+ */
+typedef struct {
+ uint16_t len;
+ uint8_t data[];
+} knot_rdata_t;
+
+/*!
+ * \brief Inits rdata structure.
+ *
+ * \param rdata Rdata structure to be initialized. At least knot_rdata_size bytes
+ * must fit into it!
+ * \param len Rdata length.
+ * \param data Rdata itself.
+ */
+inline static void knot_rdata_init(knot_rdata_t *rdata, uint16_t len, const uint8_t *data)
+{
+ assert(rdata);
+ rdata->len = len;
+ if (rdata->len > 0) {
+ assert(data);
+ memcpy(rdata->data, data, len);
+ }
+}
+
+/*!
+ * \brief Returns actual size of the rdata structure for given rdata length.
+ *
+ * \param len Rdata length.
+ *
+ * \return Actual structure size.
+ */
+inline static size_t knot_rdata_size(uint16_t len)
+{
+ return sizeof(uint16_t) + len + (len & 1);
+}
+
+/*!
+ * \brief Canonical comparison of two rdata structures.
+ *
+ * \param rdata1 First rdata to compare.
+ * \param rdata2 Second rdata to compare.
+ *
+ * \retval = 0 if rdata1 == rdata2.
+ * \retval < 0 if rdata1 < rdata2.
+ * \retval > 0 if rdata1 > rdata2.
+ */
+inline static int knot_rdata_cmp(const knot_rdata_t *rdata1, const knot_rdata_t *rdata2)
+{
+ assert(rdata1);
+ assert(rdata2);
+
+ size_t common_len = (rdata1->len <= rdata2->len) ? rdata1->len : rdata2->len;
+
+ int cmp = memcmp(rdata1->data, rdata2->data, common_len);
+ if (cmp == 0 && rdata1->len != rdata2->len) {
+ cmp = rdata1->len < rdata2->len ? -1 : 1;
+ }
+ return cmp;
+}
+
+/*! @} */