c-libp2p/crypto/encoding/base16.c

76 lines
2.2 KiB
C

#include <string.h>
#include <stdio.h>
#include "libp2p/crypto/encoding/base16.h"
/**
* Encode in Base16 format
* @param incoming the incoming bytes
* @param incoming_length the length of the incoming bytes
* @param results where to put the results
* @param results_length the size of the buffer, and returns the actual length used
* @returns true(1) on success
*/
int libp2p_crypto_encoding_base16_encode(const unsigned char* incoming, size_t incoming_length, unsigned char* results, size_t* results_length) {
// the size will be 2x the size of incoming, so check that
if (*results_length < incoming_length * 2)
return 0;
// clear out the results variable
memset(results, 0, *results_length);
*results_length = 0;
for(int i = 0; i < incoming_length; i++) {
unsigned char buf[3];
sprintf(buf, "%02x", incoming[i]);
results[i * 2] = buf[0];
results[i * 2 + 1] = buf[1];
*results_length += 2;
}
return 1;
}
/**
* Calculate the size of the buffer necessary to encode
* @param incoming_length the length of the incoming value
* @returns the size of the buffer necessary to hold the encoded bytes
*/
int libp2p_crypto_encoding_base16_encode_size(size_t incoming_length) {
return incoming_length * 2;
}
/**
* Decode from Base16 format
* @param incoming the incoming base16 encoded string
* @param incoming_length the length of the incoming string (no need to include null)
* @param results where to put the results
* @param results_length the size of the buffer, and returns the actual length used
* @returns true(1) on success
*/
int libp2p_crypto_encoding_base16_decode(const unsigned char* incoming, size_t incoming_length, unsigned char* results, size_t* results_length) {
// buffer too small
if (*results_length < incoming_length / 2)
return 0;
memset(results, 0, *results_length);
unsigned char* pos = (char*)incoming;
for(int i = 0; i < incoming_length / 2; i++) {
sscanf(pos, "%2hhx", &results[i]);
pos += 2;
}
return 1;
}
/**
* Calculate the size of the buffer necessary to decode
* @param incoming_length the length of the incoming value
* @returns the size of the buffer necessary to hold the decoded bytes
*/
int libp2p_crypto_encoding_base16_decode_size(size_t incoming_length) {
return incoming_length / 2;
}