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Diffstat (limited to '')
-rw-r--r-- | src/libknot/rdata.h | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/src/libknot/rdata.h b/src/libknot/rdata.h new file mode 100644 index 0000000..e3a818b --- /dev/null +++ b/src/libknot/rdata.h @@ -0,0 +1,97 @@ +/* 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; +} + +/*! @} */ |