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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 15:24:08 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 15:24:08 +0000 |
commit | f449f278dd3c70e479a035f50a9bb817a9b433ba (patch) | |
tree | 8ca2bfb785dda9bb4d573acdf9b42aea9cd51383 /src/utils/common/hex.c | |
parent | Initial commit. (diff) | |
download | knot-upstream/3.2.6.tar.xz knot-upstream/3.2.6.zip |
Adding upstream version 3.2.6.upstream/3.2.6upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | src/utils/common/hex.c | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/src/utils/common/hex.c b/src/utils/common/hex.c new file mode 100644 index 0000000..9683446 --- /dev/null +++ b/src/utils/common/hex.c @@ -0,0 +1,82 @@ +/* Copyright (C) 2017 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/>. + */ + +#include <assert.h> +#include <stdint.h> +#include <stdlib.h> +#include <string.h> +#include "libknot/libknot.h" +#include "contrib/ctype.h" +#include "contrib/tolower.h" + +/*! + * \brief Convert HEX char to byte. + * \note Expects valid lowercase letters. + */ +static uint8_t hex_to_num(int c) +{ + if (c >= '0' && c <= '9') { + return c - '0'; + } else { + return c - 'a' + 10; + } +} + +/*! + * \brief Convert string encoded in hex to bytes. + */ +int hex_decode(const char *input, uint8_t **output, size_t *output_size) +{ + if (!input || input[0] == '\0' || !output || !output_size) { + return KNOT_EINVAL; + } + + // input validation (length and content) + + size_t input_size = strlen(input); + if (input_size % 2 != 0) { + return KNOT_EMALF; + } + + for (size_t i = 0; i < input_size; i++) { + if (!is_xdigit(input[i])) { + return KNOT_EMALF; + } + } + + // output allocation + + size_t result_size = input_size / 2; + assert(result_size > 0); + uint8_t *result = malloc(result_size); + if (!result) { + return KNOT_ENOMEM; + } + + // conversion + + for (size_t i = 0; i < result_size; i++) { + int high_nib = knot_tolower(input[2 * i]); + int low_nib = knot_tolower(input[2 * i + 1]); + + result[i] = hex_to_num(high_nib) << 4 | hex_to_num(low_nib); + } + + *output = result; + *output_size = result_size; + + return KNOT_EOK; +} |