C++ hex string to byte array

I'm trying to send a string of hex values through udp,

11 22 33 44 37 4D 58 33 38 4C 30 39 4开发者_Go百科7 35 35 34 31 35 31 04 D7 52 FF 0F 03 43 2D AA

using UdpClient in C++.

What's the best way to convert string^ to  array< Byte >^ ?

This works for me, although I haven't tested the error-detection all that well.

ref class Blob
{
    static short* lut;
    static Blob()
    {
        lut = new short['f']();
        for( char c = 0; c < 10; c++ ) lut['0'+c] = 1+c;
        for( char c = 0; c < 6; c++ ) lut['a'+c] = lut['A'+c] = 11+c;
    }
public:
    static bool TryParse(System::String^ s, array<System::Byte>^% arr)
    {
        array<System::Byte>^ results = gcnew array<System::Byte>(s->Length/2);
        int index = 0;
        int accum = 0;
        bool accumReady = false;
        for each (System::Char c in s) {
            if (c == ' ') {
                if (accumReady) {
                    if (accum & ~0xFF) return false;
                    results[index++] = accum;
                    accum = 0;
                }
                accumReady = false;
                continue;
            }
            accum <<= 4;
            accum |= (c <= 'f')? lut[c]-1: -1;
            accumReady = true;
        }
        if (accumReady) {
            if (accum & ~0x00FF) return false;
            results[index++] = accum;
        }
        arr = gcnew array<System::Byte>(index);
        System::Array::Copy(results, arr, index);
        return true;
    }
};

If you're trying to send that as ascii bytes, then you probably want System::Text::Encoding::ASCII::GetBytes(String^).

If you want to convert the string to a bunch of bytes first (so first byte sent is 0x11), you'll want to split your string based on whitespace, call Convert::ToByte(String^, 16) on each, and put them into an array to send.