141 lines
3.7 KiB
C
141 lines
3.7 KiB
C
/**
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* Content ID
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "ipfs/cid/cid.h"
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#include "libp2p/crypto/encoding/base58.h"
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#include "ipfs/multibase/multibase.h"
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#include "mh/multihash.h"
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#include "multiaddr/varint.h"
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/**
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* Create a new CID based on the given hash
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* @param version the version
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* @param hash the multihash
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* @param hash_length the length of the multihash in bytes
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* @param codec the codec to be used (NOTE: For version 0, this should be CID_PROTOBUF)
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* @param cid where to put the results
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* @returns true(1) on success
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*/
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int ipfs_cid_new(int version, unsigned char* hash, size_t hash_length, const char codec, struct Cid** ptrToCid) {
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// allocate memory
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*ptrToCid = (struct Cid*)malloc(sizeof(struct Cid));
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struct Cid* cid = *ptrToCid;
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if (cid == NULL)
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return 0;
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cid->hash = malloc(sizeof(unsigned char) * hash_length);
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if (cid->hash == NULL) {
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free(cid);
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return 0;
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}
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// assign values
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cid->version = version;
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cid->codec = codec;
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memcpy(cid->hash, hash, hash_length);
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cid->hash_length = hash_length;
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return 1;
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}
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/***
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* Free the resources from a Cid
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* @param cid the struct
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* @returns 1
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*/
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int ipfs_cid_free(struct Cid* cid) {
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if (cid->hash != NULL)
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free(cid->hash);
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free(cid);
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return 1;
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}
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/***
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* Fill a Cid struct based on a base 58 encoded string
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* @param incoming the string
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* @param incoming_size the size of the string
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* @cid the Cid struct to fill
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* @return true(1) on success
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*/
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int ipfs_cid_decode_from_string(const unsigned char* incoming, size_t incoming_length, struct Cid** cid) {
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int retVal = 0;
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if (incoming_length < 2)
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return 0;
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// is this a sha_256 multihash?
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if (incoming_length == 46 && incoming[0] == 'Q' && incoming[1] == 'm') {
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size_t hash_length = libp2p_crypto_encoding_base58_decode_size(incoming_length);
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unsigned char hash[hash_length];
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unsigned char* ptr = hash;
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retVal = libp2p_crypto_encoding_base58_decode(incoming, incoming_length, &ptr, &hash_length);
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if (retVal == 0)
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return 0;
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// now we have the hash, build the object
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return ipfs_cid_new(0, hash, hash_length, CID_PROTOBUF, cid);
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}
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// TODO: finish this
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/*
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// it wasn't a sha_256 multihash, try to decode it using multibase
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size_t buffer_size = multibase_decode_size(incoming_length);
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if (buffer_size == 0)
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return 0;
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unsigned char buffer[buffer_size];
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memset(buffer, 0, buffer_size);
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retVal = multibase_decode(incoming, incoming_length, buffer, buffer_size, &buffer_size);
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if (retVal == 0)
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return 0;
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return cid_cast(buffer, buffer_size, cid);
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*/
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return 0;
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}
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/***
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* Turn a multibase decoded string of bytes into a Cid struct
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* @param incoming the multibase decoded array
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* @param incoming_size the size of the array
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* @param cid the Cid structure to fill
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*/
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int ipfs_cid_cast(unsigned char* incoming, size_t incoming_size, struct Cid* cid) {
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// this is a multihash
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if (incoming_size == 34 && incoming[0] == 18 && incoming[1] == 32) {
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cid->hash_length = mh_multihash_length(incoming, incoming_size);
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cid->codec = CID_PROTOBUF;
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cid->version = 0;
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mh_multihash_digest(incoming, incoming_size, &cid->hash, &cid->hash_length);
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return 1;
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}
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// This is not a multihash. Perhaps it is using varints. Try to peel the information out of the bytes.
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// first the version
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int pos = 0, retVal = 0;
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size_t num_bytes = 0;
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num_bytes = uvarint_decode32(&incoming[pos], incoming_size - pos, &cid->version);
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if (num_bytes < 0 || cid->version > 1 || cid->version < 0)
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return 0;
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pos = num_bytes;
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// now the codec
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uint32_t codec = 0;
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num_bytes = uvarint_decode32(&incoming[pos], incoming_size - pos, &codec);
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if (num_bytes < 0)
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return 0;
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cid->codec = codec;
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pos += num_bytes;
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// now what is left
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cid->hash_length = incoming_size - pos;
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cid->hash = &incoming[pos];
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return 1;
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}
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