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/**
* libkeccak – Keccak-family hashing library
*
* Copyright © 2014 Mattias Andrée (maandree@member.fsf.org)
*
* This library is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This library 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
#include "hex.h"
#include <string.h>
/**
* Convert a binary hashsum to lower case hexadecimal representation
*
* @param output Output array, should have an allocation size of at least `2 * n + 1`
* @param hashsum The hashsum to convert
* @param n The size of `hashsum`
*/
void libkeccak_behex_lower(char* restrict output, const char* restrict hashsum, size_t n)
{
output[2 * n] = '\0';
while (n--)
{
output[2 * n + 0] = "0123456789abcdef"[(hashsum[n] >> 4) & 15];
output[2 * n + 1] = "0123456789abcdef"[(hashsum[n] >> 0) & 15];
}
}
/**
* Convert a binary hashsum to upper case hexadecimal representation
*
* @param output Output array, should have an allocation size of at least `2 * n + 1`
* @param hashsum The hashsum to convert
* @param n The size of `hashsum`
*/
void libkeccak_behex_upper(char* restrict output, const char* restrict hashsum, size_t n)
{
output[2 * n] = '\0';
while (n--)
{
output[2 * n + 0] = "0123456789ABCDEF"[(hashsum[n] >> 4) & 15];
output[2 * n + 1] = "0123456789ABCDEF"[(hashsum[n] >> 0) & 15];
}
}
/**
* Convert a hexadecimal hashsum (both lower case, upper
* case and mixed is supported) to binary representation
*
* @param output Output array, should have an allocation size of at least `strlen(hashsum) / 2`
* @param hashsum The hashsum to convert
*/
void libkeccak_unhex(char* restrict output, const char* restrict hashsum)
{
size_t n = strlen(hashsum) / 2;
while (n--)
{
char a = hashsum[2 * n + 0];
char b = hashsum[2 * n + 1];
a = (char)((a & 15) + (a > '9' ? 9 : 0));
b = (char)((b & 15) + (b > '9' ? 9 : 0));
output[n] = (char)((a << 4) | b);
}
}
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