base64_decode()

fl::vector< fl::u8 > fl::base64_decode

(

const fl::string &

encoded

)

Definition at line 62 of file base64.cpp.hpp.

                                                      {
    fl::vector<fl::u8> out;
    if (encoded.empty()) return out;
 
    fl::size len = encoded.size();
 
    // Validate length is multiple of 4
    if (len % 4 != 0) return out;
 
    fl::size out_len = (len / 4) * 3;
    if (len >= 1 && encoded[len - 1] == '=') out_len--;
    if (len >= 2 && encoded[len - 2] == '=') out_len--;
    out.reserve(out_len);
 
    for (fl::size i = 0; i < len; i += 4) {
        int a = base64_char_index(encoded[i]);
        int b = base64_char_index(encoded[i + 1]);
        int c = (encoded[i + 2] == '=') ? 0 : base64_char_index(encoded[i + 2]);
        int d = (encoded[i + 3] == '=') ? 0 : base64_char_index(encoded[i + 3]);
 
        if (a < 0 || b < 0 || c < 0 || d < 0) {
            return fl::vector<fl::u8>(); // invalid character
        }
 
        fl::u32 triple = (fl::u32(a) << 18) | (fl::u32(b) << 12) |
                          (fl::u32(c) << 6) | fl::u32(d);
 
        out.push_back((triple >> 16) & 0xFF);
        if (encoded[i + 2] != '=') {
            out.push_back((triple >> 8) & 0xFF);
        }
        if (encoded[i + 3] != '=') {
            out.push_back(triple & 0xFF);
        }
    }
 
    return out;
}

References fl::basic_string::empty(), fl::vector< T >::push_back(), fl::vector< T >::reserve(), and fl::basic_string::size().

Referenced by fl::detail::JsonToType< fl::vector< fl::u8 >, void >::convert().

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