1 files changed, 101 insertions, 0 deletions
diff --git a/src/libknot/rdata.h b/src/libknot/rdata.h
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+/*  Copyright (C) 2019 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 <https://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);
+		if (len & 1) { // Initialize possible padding to mute analytical tools.
+			rdata->data[len] = 0;
+		}
+	}
+}
+
+/*!
+ * \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;
+}
+
+/*! @} */