Added name compression API (not yet finished).

src/libknot/packet/compr.h

+/*!
+ * \file compr.h
+ *
+ * \author Marek Vavrusa <marek.vavrusa@nic.cz>
+ *
+ * \brief Name compression API.
+ *
+ * \addtogroup libknot
+ * @{
+ */
+/*  Copyright (C) 2013 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/>.
+ */
+
+#ifndef _KNOT_COMPR_H_
+#define _KNOT_COMPR_H_
+
+#include "libknot/packet/wire.h"
+
+enum {
+	COMPR_HINT_NONE = 0,
+	COMPR_HINT_NOCOMP  = 1,
+	COMPR_HINT_QNAME = KNOT_WIRE_HEADER_SIZE
+};
+
+enum {
+	COMPR_HINT_OWNER = 0,
+	COMPR_HINT_RDATA = 1,
+	COMPR_HINT_COUNT = 4
+};
+
+typedef struct {
+	uint16_t pos;
+	uint16_t flags;
+	uint16_t compress_ptr[COMPR_HINT_COUNT];
+} knot_rrinfo_t;
+
+/*!
+ * \brief Holds information about compressed domain names in packet.
+ *
+ * Used only to pass information between functions.
+ *
+ */
+typedef struct knot_compr {
+	uint8_t *wire;
+	size_t wire_pos;
+	knot_rrinfo_t *rrinfo;
+	struct {
+		uint16_t pos;
+		uint8_t labels;
+	} suffix;
+} knot_compr_t;
+
+static inline uint16_t knot_pkt_compr_hint(const knot_rrinfo_t *info, uint16_t hint_id)
+{
+	if (hint_id < COMPR_HINT_COUNT) {
+		return info->compress_ptr[hint_id];
+	} else {
+		return COMPR_HINT_NONE;
+	}
+}
+
+static inline void knot_pkt_compr_hint_set(knot_rrinfo_t *info, uint16_t hint_id, uint16_t val)
+{
+	if (hint_id < COMPR_HINT_COUNT && val < KNOT_WIRE_PTR_MAX) {
+		info->compress_ptr[hint_id] = val;
+	}
+}
+
+#endif /* _KNOT_COMPR_H_ */
+
+/*! @} */