IO#winsize=

static VALUE
console_set_winsize(VALUE io, VALUE size)
{
    rb_console_size_t ws;
#if defined _WIN32
    HANDLE wh;
    int newrow, newcol;
    COORD oldsize;
    SMALL_RECT oldwindow;
#endif
    VALUE row, col, xpixel, ypixel;
    const VALUE *sz;
    rb_len_t sizelen;
    int fd;

    size = rb_Array(size);
    if ((sizelen = RARRAY_LEN(size)) != 2 && sizelen != 4) {
        rb_raise(rb_eArgError, "wrong number of arguments (given %"PRIdLEN", expected 2 or 4)", sizelen);
    }
    sz = RARRAY_CONST_PTR(size);
    row = sz[0], col = sz[1], xpixel = ypixel = Qnil;
    if (sizelen == 4) xpixel = sz[2], ypixel = sz[3];
    fd = GetWriteFD(io);
#if defined TIOCSWINSZ
    ws.ws_row = ws.ws_col = ws.ws_xpixel = ws.ws_ypixel = 0;
#define SET(m) ws.ws_##m = NIL_P(m) ? 0 : (unsigned short)NUM2UINT(m)
    SET(row);
    SET(col);
    SET(xpixel);
    SET(ypixel);
#undef SET
    if (!setwinsize(fd, &ws)) sys_fail(io);
#elif defined _WIN32
    wh = (HANDLE)rb_w32_get_osfhandle(fd);
#define SET(m) new##m = NIL_P(m) ? 0 : (unsigned short)NUM2UINT(m)
    SET(row);
    SET(col);
#undef SET
    if (!NIL_P(xpixel)) (void)NUM2UINT(xpixel);
    if (!NIL_P(ypixel)) (void)NUM2UINT(ypixel);
    if (!GetConsoleScreenBufferInfo(wh, &ws)) {
        rb_syserr_fail(LAST_ERROR, "GetConsoleScreenBufferInfo");
    }
    oldsize = ws.dwSize;
    oldwindow = ws.srWindow;
    if (ws.srWindow.Right + 1 < newcol) {
        ws.dwSize.X = newcol;
    }
    if (ws.dwSize.Y < newrow) {
        ws.dwSize.Y = newrow;
    }
    /* expand screen buffer first if needed */
    if (!SetConsoleScreenBufferSize(wh, ws.dwSize)) {
        rb_syserr_fail(LAST_ERROR, "SetConsoleScreenBufferInfo");
    }
    /* refresh ws for new dwMaximumWindowSize */
    if (!GetConsoleScreenBufferInfo(wh, &ws)) {
        rb_syserr_fail(LAST_ERROR, "GetConsoleScreenBufferInfo");
    }
    /* check new size before modifying buffer content */
    if (newrow <= 0 || newcol <= 0 ||
        newrow > ws.dwMaximumWindowSize.Y ||
        newcol > ws.dwMaximumWindowSize.X) {
        SetConsoleScreenBufferSize(wh, oldsize);
        /* remove scrollbar if possible */
        SetConsoleWindowInfo(wh, TRUE, &oldwindow);
        rb_raise(rb_eArgError, "out of range winsize: [%d, %d]", newrow, newcol);
    }
    /* shrink screen buffer width */
    ws.dwSize.X = newcol;
    /* shrink screen buffer height if window height were the same */
    if (oldsize.Y == ws.srWindow.Bottom - ws.srWindow.Top + 1) {
        ws.dwSize.Y = newrow;
    }
    ws.srWindow.Left = 0;
    ws.srWindow.Right = newcol - 1;
    ws.srWindow.Bottom = ws.srWindow.Top + newrow -1;
    if (ws.dwCursorPosition.Y > ws.srWindow.Bottom) {
        console_scroll(io, ws.dwCursorPosition.Y - ws.srWindow.Bottom);
        ws.dwCursorPosition.Y = ws.srWindow.Bottom;
        console_goto(io, INT2FIX(ws.dwCursorPosition.Y), INT2FIX(ws.dwCursorPosition.X));
    }
    if (ws.srWindow.Bottom > ws.dwSize.Y - 1) {
        console_scroll(io, ws.srWindow.Bottom - (ws.dwSize.Y - 1));
        ws.dwCursorPosition.Y -= ws.srWindow.Bottom - (ws.dwSize.Y - 1);
        console_goto(io, INT2FIX(ws.dwCursorPosition.Y), INT2FIX(ws.dwCursorPosition.X));
        ws.srWindow.Bottom = ws.dwSize.Y - 1;
    }
    ws.srWindow.Top = ws.srWindow.Bottom - (newrow - 1);
    /* perform changes to winsize */
    if (!SetConsoleWindowInfo(wh, TRUE, &ws.srWindow)) {
        int last_error = LAST_ERROR;
        SetConsoleScreenBufferSize(wh, oldsize);
        rb_syserr_fail(last_error, "SetConsoleWindowInfo");
    }
    /* perform screen buffer shrinking if necessary */
    if ((ws.dwSize.Y < oldsize.Y || ws.dwSize.X < oldsize.X) &&
        !SetConsoleScreenBufferSize(wh, ws.dwSize)) {
        rb_syserr_fail(LAST_ERROR, "SetConsoleScreenBufferInfo");
    }
    /* remove scrollbar if possible */
    if (!SetConsoleWindowInfo(wh, TRUE, &ws.srWindow)) {
        rb_syserr_fail(LAST_ERROR, "SetConsoleWindowInfo");
    }
#endif
    return io;
}