c-ipfs/multibase/multibase.c

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2016-11-14 02:01:51 +00:00
#include <stdlib.h>
#include <string.h>
#include "ipfs/multibase/multibase.h"
#include "libp2p/crypto/encoding/base58.h"
#include "libp2p/crypto/encoding/base16.h"
/**
* Encode data in multibase format. NOTE: currently only supports MULTIBASE_BASE58_BTC and MULTIBASE_BASE16
* @param base the format to use (i.e. MULTIBASE_BASE58_BTC)
* @param incoming the data to encode
* @param incoming_length the length of the data to encode
* @param results where to put the results
* @param results_max_length the size of the results buffer
* @param results_length the size of the results after being encoded
* @returns true(1) on success
*/
int multibase_encode(const char base, const unsigned char* incoming, size_t incoming_length, unsigned char* results, size_t results_max_length, size_t* results_length) {
*results_length = results_max_length;
int retVal = 0;
switch (base) {
case (MULTIBASE_BASE58_BTC):
retVal = libp2p_crypto_encoding_base58_encode(incoming, incoming_length, &results, results_length);
break;
case(MULTIBASE_BASE16):
retVal = libp2p_crypto_encoding_base16_encode(incoming, incoming_length, results, results_length);
break;
default: // unsupported format
return 0;
}
// check to see if there was a problem
if (retVal == 0)
return 0;
// we have the hash, now add the code to the first byte (if there is room)
if (*results_length >= results_max_length) { // It could be equal, but should never be greater. But just in case.
return 0; // buffer isn't big enough
}
memcpy(&results[1], results, *results_length);
results[0] = base;
*results_length += 1;
return 1;
}
/***
* Calculates the size of the buffer neccessary to encode the incoming byte array
* @param base the encoding to use
* @param incoming the incoming array of bytes
* @param incoming_length the length of the array in bytes
* @returns the appropriate size of the buffer
*/
int multibase_encode_size(const char base, const unsigned char* incoming, size_t incoming_length) {
switch (base) {
case (MULTIBASE_BASE58_BTC):
return libp2p_crypto_encoding_base58_encode_size(incoming_length) + 1;
case (MULTIBASE_BASE16):
return libp2p_crypto_encoding_base16_encode_size(incoming_length);
}
return 0;
}
/**
* Decode data that was encoded in multibase format
* @param incoming the data to decode
* @param incoming_length the length of the data to decode
* @param results where to put the results
* @param results_max_length the size of the results buffer
* @param results_length the size of the results after being encoded
* @returns true(1) on success
*/
int multibase_decode(const unsigned char* incoming, size_t incoming_length, unsigned char* results, size_t results_max_length, size_t* results_length) {
*results_length = results_max_length;
int retVal = 0;
const char base = incoming[0];
switch (base) {
case (MULTIBASE_BASE58_BTC):
retVal = libp2p_crypto_encoding_base58_decode(&incoming[1], incoming_length - 1, &results, results_length);
break;
case(MULTIBASE_BASE16):
retVal = libp2p_crypto_encoding_base16_decode(&incoming[1], incoming_length - 1, results, results_length);
break;
default: // unsupported format
return 0;
}
// check to see if there was a problem
if (retVal == 0)
return 0;
return 1;
}
/***
* Calculates the size of the buffer neccessary to decode the incoming byte array
* @param base the encoding to use
* @param incoming the incoming array of bytes
* @param incoming_length the length of the array in bytes
* @returns the appropriate size of the buffer
*/
int multibase_decode_size(const char base, const unsigned char* incoming, size_t incoming_length) {
switch (base) {
case (MULTIBASE_BASE58_BTC):
return libp2p_crypto_encoding_base58_decode_size(incoming_length) + 1;
case (MULTIBASE_BASE16):
return libp2p_crypto_encoding_base16_decode_size(incoming_length);
}
return 0;
}