core-lightning/common/hash_u5.c

#include <ccan/endian/endian.h>
#include <common/hash_u5.h>
#include <string.h>

void hash_u5_init(struct hash_u5 *hu5, const char *hrp)
{
        hu5->buf = 0;
        hu5->num_bits = 0;
        sha256_init(&hu5->hash);
        sha256_update(&hu5->hash, hrp, strlen(hrp));
}

void hash_u5(struct hash_u5 *hu5, const u8 *u5, size_t len)
{
        size_t bits = len * 5;

        while (bits) {
                size_t n = 5;

                if (bits < n)
                        n = bits;

                hu5->buf <<= n;
                hu5->buf |= (*u5 >> (5-n));
                bits -= n;
                hu5->num_bits += n;

                if (n == 5)
                        u5++;

                if (hu5->num_bits >= 32) {
                        be32 be32 = cpu_to_be32(hu5->buf >> (hu5->num_bits-32));
                        sha256_update(&hu5->hash, &be32, sizeof(be32));
                        hu5->num_bits -= 32;
                }
        }
}

void hash_u5_done(struct hash_u5 *hu5, struct sha256 *res)
{
        if (hu5->num_bits) {
                be32 be32 = cpu_to_be32(hu5->buf << (32 - hu5->num_bits));

                sha256_update(&hu5->hash, &be32, (hu5->num_bits + 7) / 8);
        }
        sha256_done(&hu5->hash, res);
}