c-ipfs/include/ipfs/cid/cid.h

/***
 * A content id
 */

#ifndef __IPFS_CID_CID_H
#define __IPFS_CID_CID_H

#include <stddef.h>
#include "protobuf.h"

// these are multicodec packed content types. They should match
// the codes described in the authoratative document:
// https://github.com/multiformats/multicodec/blob/master/table.csv
#define CID_RAW 0x55
#define CID_DAG_PROTOBUF 0x70
#define CID_DAG_CBOR 0x71
#define CID_GIT_RAW 0x78
#define CID_ETHEREUM_BLOCK 0x90
#define CID_ETHEREUM_BLOCKLIST 0x91
#define CID_ETHEREUM_TRIE 0x92
#define CID_ETHEREUM_TX 0x93
#define CID_ETHEREUM_TX_RECEIPT_TRIE 0x94
#define CID_ETHEREUM_TX_RECEIPT 0x95
#define CID_ETHEREUM_STATE_TRIE 0x96
#define CID_ETHEREUM_ACCOUNT_SNAPSHOT 0x97
#define CID_ETHEREUM_STORAGE_TRIE 0x98
#define CID_BITCOIN_BLOCK 0xb0
#define CID_BITCOIN_TX 0xb1
#define CID_ZCASH_BLOCK 0xc0
#define CID_ZCASH_TX 0xc1

/***
 * A note about CID versions:
 * Version 0 only contained the multihash address. The extra parameters of multibase,
 * multicodec, cid-version were implied (base58btc, protobuf-mdag, and cidv0
 * respectively) are implied.
 */

struct Cid {
	int version; // CID version
	int codec; // codec used (i.e. CID_RAW, CID_PROTOBUF
	unsigned char* hash; // the multihash
	size_t hash_length; // the length of hash
};

struct CidSet {
    struct Cid *cid;
    struct CidSet *next;
};

/***
 * encode a Cid into a protobuf array of bytes
 * @param incoming the incoming Cid struct
 * @param buffer the buffer
 * @param max_buffer_length the length of the buffer
 * @param bytes_written the number of bytes written
 */
int ipfs_cid_protobuf_encode(const struct Cid* incoming, unsigned char* buffer, size_t max_buffer_length, size_t* bytes_written);

/***
 * decode an array of bytes into a Cid structure
 * @param buffer the incming array of bytes
 * @param buffer_length the length of the buffer
 * @param output the Cid struct NOTE: all allocations are made by this function. Be sure to call free
 * @returns true(1) on success
 */
int ipfs_cid_protobuf_decode(unsigned char* buffer, size_t buffer_length, struct Cid** output);

/***
 * Returns a safe estimate of the required buffer size to encode the Cid struct
 * @param incoming the struct to encode
 * @returns the number of approximate bytes
 */
size_t ipfs_cid_protobuf_encode_size(const struct Cid* incoming);

/**
 * Create a new CID based on the given hash
 * @param version the version
 * @param hash the multihash
 * @param hash_length the length of the multihash in bytes
 * @param codec the codec to be used (NOTE: For version 0, this should be CID_PROTOBUF)
 * @returns the Cid, or NULL if there was a problem
 */
struct Cid* ipfs_cid_new(int version, const unsigned char* hash, size_t hash_length, const char codec);

/***
 * Free the resources from a Cid
 * @param cid the struct
 * @returns 1
 */
int ipfs_cid_free(struct Cid* cid);

/***
 * Make a copy of a Cid
 * @param original the original
 * @returns a copy of the original
 */
struct Cid* ipfs_cid_copy(const struct Cid* original);

/***
 * Fill a Cid struct based on a base 58 encoded string
 * @param incoming the string
 * @param incoming_size the size of the string
 * @cid the Cid struct to fill
 * @return true(1) on success
 */
int ipfs_cid_decode_hash_from_base58(const unsigned char* incoming, size_t incoming_length, struct Cid** cid);

/**
 * Turn a cid into a base 58 of a multihash of the cid hash
 * @param cid the cid to work with
 * @param buffer where to put the results
 * @param max_buffer_length the maximum space reserved for the results
 * @returns true(1) on success
 */
int ipfs_cid_hash_to_base58(const unsigned char* hash, size_t hash_length, unsigned char* buffer, size_t max_buffer_length);

/***
 * Turn the hash of this CID into a c string
 * @param cid the cid
 * @param result a place to allocate and store the string
 * @returns a pointer to the string (*result) or NULL if there was a problem
 */
char* ipfs_cid_to_string(const struct Cid* cid, char **result);

/***
 * 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);

struct CidSet *ipfs_cid_set_new ();
void ipfs_cid_set_destroy (struct CidSet **set);
int ipfs_cid_set_add (struct CidSet *set, struct Cid *cid, int visit);
int ipfs_cid_set_has (struct CidSet *set, struct Cid *cid);
int ipfs_cid_set_remove (struct CidSet *set, struct Cid *cid);
int ipfs_cid_set_len (struct CidSet *set);
unsigned char **ipfs_cid_set_keys (struct CidSet *set);
int ipfs_cid_set_foreach (struct CidSet *set, int (*func)(struct Cid *));

/**
 * Compare two cids
 * @param a side A
 * @param b side B
 * @returns < 0 if side A is greater, > 0 if side B is greater, or 0 if equal
 */
int ipfs_cid_compare(const struct Cid* a, const struct Cid* b);

#endif