int offset = 0;

    int mod = 0;
    if (keysym.mod & KMOD_SHIFT)
        mod |= MOD_SHIFT;

        offset = ctrl_offset;
    else if (keysym.mod & KMOD_SHIFT)
        offset = shift_offset;

        mod |= MOD_CTRL;
    if (keysym.mod & KMOD_ALT)
        mod |= MOD_ALT;
    // This is arbitrary, but here's the current mappings.
    // 0-256: ASCII, Crawl arrow keys
    // 0-1k : Other SDL keys (F1, Windows keys, etc...) and modifiers
    // 1k-3k: Non-ASCII with modifiers other than just shift or just ctrl.
    // 3k+  : ASCII with the alt modifier.

    // Match what curses returns.
    enum function_keys
    {
        F1 = 265,
        F2, F3, F4, F5, F6, F7, F8, F9, F10, F11, F12, F13, F14, F15
    };

    int offset = mod ? 1000 + 256 * mod : 0;
    int numpad_offset = 0;
    if (mod == MOD_CTRL)
        numpad_offset = ctrl_offset;
    else if (mod == KMOD_SHIFT)
        numpad_offset = shift_offset;
    else
        numpad_offset = offset;

        return CK_ENTER;

        return CK_ENTER + offset;

        return CK_BKSP;

        return CK_BKSP + offset;

        return CK_ESCAPE;

        return CK_ESCAPE + offset;

        return CK_DELETE;

        return CK_DELETE + offset;

        return F1;

        return F2;

        return F3;

        return F4;

        return F5;

        return F6;

        return F7;

        return F8;

        return F9;

        return F10;

        return F11;

        return F12;

        return F13;

        return F14;

        return F15;

    case SDLK_NUMLOCK:
    case SDLK_CAPSLOCK:
    case SDLK_SCROLLOCK:
    case SDLK_RMETA:
    case SDLK_LMETA:
    case SDLK_LSUPER:
    case SDLK_RSUPER:
    case SDLK_MODE:
    case SDLK_COMPOSE:
    case SDLK_HELP:
    case SDLK_PRINT:
    case SDLK_SYSREQ:
    case SDLK_BREAK:
    case SDLK_MENU:
    case SDLK_POWER:
    case SDLK_EURO:
    case SDLK_UNDO:
        ASSERT(keysym.sym >= SDLK_F1 && keysym.sym <= SDLK_UNDO);
        return keysym.sym + (SDLK_UNDO - SDLK_F1 + 1) * mod;

        return CK_CLEAR + offset;

        return CK_CLEAR + numpad_offset;

        return CK_UP + offset;

        return CK_UP + numpad_offset;

        return CK_DOWN + offset;

        return CK_DOWN + numpad_offset;

        return CK_LEFT + offset;

        return CK_LEFT + numpad_offset;

        return CK_RIGHT + offset;

        return CK_RIGHT + numpad_offset;

        return CK_INSERT + offset;

        return CK_INSERT + numpad_offset;

        return CK_HOME + offset;

        return CK_HOME + numpad_offset;

        return CK_END + offset;

        return CK_END + numpad_offset;

        return CK_CLEAR + offset;

        return CK_CLEAR + numpad_offset;

        return CK_PGUP + offset;

        return CK_PGUP + numpad_offset;

        return CK_PGDN + offset;

        return CK_PGDN + numpad_offset;

    // Alt does not get baked into keycodes like shift and ctrl, so handle it.
    int key_offset = (mod & MOD_ALT) ? 3000 : 0;

    return is_ascii ? keysym.unicode & 0x7F : 0;

    return is_ascii ? (keysym.unicode & 0x7F) + key_offset : 0;