Function scHttpWebSocketBase64Encode

Libraries/Http/HttpWebSocket.cpp:108–143

}

static SC::Result scHttpWebSocketBase64Encode(SC::Span<const uint8_t> data, SC::Span<char> storage,
                                              SC::StringSpan& output)
{
    const size_t encodedLength = ((data.sizeInBytes() + 2) / 3) * 4;
    SC_TRY_MSG(storage.sizeInBytes() >= encodedLength, "HttpWebSocketHandshake base64 output too small");

    size_t inputOffset  = 0;
    size_t outputOffset = 0;
    while (inputOffset < data.sizeInBytes())
    {
        const uint32_t a = data[inputOffset++];
        const uint32_t b = inputOffset < data.sizeInBytes() ? data[inputOffset++] : 0;
        const uint32_t c = inputOffset < data.sizeInBytes() ? data[inputOffset++] : 0;
        const uint32_t n = (a << 16) | (b << 8) | c;

        storage[outputOffset++] = SC_HTTP_WEBSOCKET_BASE64[(n >> 18) & 0x3F];
        storage[outputOffset++] = SC_HTTP_WEBSOCKET_BASE64[(n >> 12) & 0x3F];
        storage[outputOffset++] =
            inputOffset - 1 <= data.sizeInBytes() ? SC_HTTP_WEBSOCKET_BASE64[(n >> 6) & 0x3F] : '=';
        storage[outputOffset++] = inputOffset <= data.sizeInBytes() ? SC_HTTP_WEBSOCKET_BASE64[n & 0x3F] : '=';
    }

    const size_t remainder = data.sizeInBytes() % 3;
    if (remainder == 1)
    {
        storage[encodedLength - 2] = '=';
        storage[encodedLength - 1] = '=';
    }
    else if (remainder == 2)
    {
        storage[encodedLength - 1] = '=';
    }

    output = {{storage.data(), encodedLength}, false, SC::StringEncoding::Ascii};
    return SC::Result(true);
}

static int scHttpWebSocketBase64Value(char value)
{