diff options
Diffstat (limited to 'util/libkeccak_unhex.c')
-rw-r--r-- | util/libkeccak_unhex.c | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/util/libkeccak_unhex.c b/util/libkeccak_unhex.c new file mode 100644 index 0000000..b32a3f3 --- /dev/null +++ b/util/libkeccak_unhex.c @@ -0,0 +1,30 @@ +/* See LICENSE file for copyright and license details. */ +#include "../common.h" + + +/** + * 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(void *restrict output_, const char *restrict hashsum) +{ + unsigned char *restrict output = output_; + size_t n = strlen(hashsum) / 2; + unsigned char a, b; + + while (n--) { + a = (unsigned char)hashsum[2 * n + 0]; + b = (unsigned char)hashsum[2 * n + 1]; + + a = (unsigned char)((a & 15) + (a > '9' ? 9 : 0)); + b = (unsigned char)((b & 15) + (b > '9' ? 9 : 0)); + + a = (unsigned char)(a << 4); + a |= b; + output[n] = a; + } +} |