mbedtls_base64_encode reports different olen's when used for size checking and when encoding - mbed-tls

14 Apr 2020


      Hi,
I don't understand why mbedtls_base64_encode returns different olen's for the same source buffer. See example below:
uint8_t s[10];
    uint8_t d[17];
    size_t sz;
    int ret;
    ret = mbedtls_base64_encode(NULL, 0, &sz, s, 10);
    // returns sz == 17
    ret = mbedtls_base64_encode(d, 17, &sz, s, 10);
    // returns sz == 16
Shouldn't it be the same?
Regards,
Frederik