/***
* Turn a multibase decoded string of bytes into a Cid struct
* @param incoming the multibase decoded array
* @param incoming_size the size of the array
* @param cid the Cid structure to fill
*/
int ipfs_cid_cast(const unsigned char* incoming, size_t incoming_size, struct Cid* cid) {
if (incoming_size == 34 && incoming[0] == 18 && incoming[1] == 32) {
// this is a multihash
cid->hash_length = mh_multihash_length(incoming, incoming_size);
cid->codec = CID_PROTOBUF;
cid->version = 0;
mh_multihash_digest(incoming, incoming_size, &cid->hash, &cid->hash_length);
return 1;
}
// This is not a multihash. Perhaps it is using varints. Try to peel the information out of the bytes.
// first the version
int pos = 0;
size_t num_bytes = 0;
cid->version = varint_decode(&incoming[pos], incoming_size - pos, &num_bytes);
if (num_bytes == 0 || cid->version > 1 || cid->version < 0)
return 0;
pos = num_bytes;
// now the codec
uint32_t codec = 0;
codec = varint_decode(&incoming[pos], incoming_size - pos, &num_bytes);
if (num_bytes == 0)
return 0;
cid->codec = codec;
pos += num_bytes;
// now what is left
cid->hash_length = incoming_size - pos;
cid->hash = (unsigned char*)(&incoming[pos]);
return 1;
}
static char *test_multihash_new_crafts_right_multihash(void) {
int error;
unsigned char buf[256]; // much bigger than needed
size_t digest_len = -1;
const unsigned char *digest = NULL;
error = mh_multihash_digest(sha1_example, sha1_example_length,
&digest, &digest_len);
mu_assert("getting digest", error == MH_E_NO_ERROR);
error = mh_new(buf, MH_H_SHA1, digest, digest_len);
mu_assert("creating multihash", error == MH_E_NO_ERROR);
mu_assert("crafted multihash is the same", memcmp(sha1_example, buf,
sha1_example_length) == 0);
return NULL;
}
