nwaku/examples/cbindings/base64.c

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#include "base64.h"
// Base64 encoding
// source: https://nachtimwald.com/2017/11/18/base64-encode-and-decode-in-c/
size_t b64_encoded_size(size_t inlen)
{
size_t ret;
ret = inlen;
if (inlen % 3 != 0)
ret += 3 - (inlen % 3);
ret /= 3;
ret *= 4;
return ret;
}
const char b64chars[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
char *b64_encode(const unsigned char *in, size_t len)
{
char *out;
size_t elen;
size_t i;
size_t j;
size_t v;
if (in == NULL || len == 0)
return NULL;
elen = b64_encoded_size(len);
out = malloc(elen+1);
out[elen] = '\0';
for (i=0, j=0; i<len; i+=3, j+=4) {
v = in[i];
v = i+1 < len ? v << 8 | in[i+1] : v << 8;
v = i+2 < len ? v << 8 | in[i+2] : v << 8;
out[j] = b64chars[(v >> 18) & 0x3F];
out[j+1] = b64chars[(v >> 12) & 0x3F];
if (i+1 < len) {
out[j+2] = b64chars[(v >> 6) & 0x3F];
} else {
out[j+2] = '=';
}
if (i+2 < len) {
out[j+3] = b64chars[v & 0x3F];
} else {
out[j+3] = '=';
}
}
return out;
}
// End of Base64 encoding