Question

Lets say I have a std::string, but the data is encoded in UTF-16.

How could I copy that data into a std::wstring, not modifying the data at all?

Also, I can’t just use std::wstring because I’m retrieving a text file online and checking the Content-Type header field to determine encoding. But using std::string to receive the data.

Answer 1

std::wstring PackUTF16(const std::string & input)
{
    if (input.size() % 2 != 0)
        throw std::invalid_argument("input length must be even");
    std::wstring result(input.size() / 2, 0);
    for (int i = 0;  i < result.size();  ++i)
    {
        result[i] = (input[2*i+1] & 0xff) << 8 | (input[2*i] & 0xff); // for little endian
        //result[i] = (input[2*i] & 0xff) << 8 | (input[2*i+1] & 0xff); // for big endian
    }
    return result;
}