Function py2reg

crates/vm/src/stdlib/winreg.rs:953–1038

(value: PyObjectRef, typ: u32, vm: &VirtualMachine)

    }

    fn py2reg(value: PyObjectRef, typ: u32, vm: &VirtualMachine) -> PyResult<Option<Vec<u8>>> {
        match typ {
            REG_DWORD => {
                if vm.is_none(&value) {
                    return Ok(Some(0u32.to_le_bytes().to_vec()));
                }
                let val = value
                    .downcast_ref::<PyInt>()
                    .ok_or_else(|| vm.new_type_error("value must be an integer"))?;
                let bigint = val.as_bigint();
                // Check for negative value - raise OverflowError
                if bigint.sign() == Sign::Minus {
                    return Err(vm.new_overflow_error("int too big to convert"));
                }
                let val = bigint
                    .to_u32()
                    .ok_or_else(|| vm.new_overflow_error("int too big to convert"))?;
                Ok(Some(val.to_le_bytes().to_vec()))
            }
            REG_QWORD => {
                if vm.is_none(&value) {
                    return Ok(Some(0u64.to_le_bytes().to_vec()));
                }
                let val = value
                    .downcast_ref::<PyInt>()
                    .ok_or_else(|| vm.new_type_error("value must be an integer"))?;
                let bigint = val.as_bigint();
                // Check for negative value - raise OverflowError
                if bigint.sign() == Sign::Minus {
                    return Err(vm.new_overflow_error("int too big to convert"));
                }
                let val = bigint
                    .to_u64()
                    .ok_or_else(|| vm.new_overflow_error("int too big to convert"))?;
                Ok(Some(val.to_le_bytes().to_vec()))
            }
            REG_SZ | REG_EXPAND_SZ => {
                if vm.is_none(&value) {
                    // Return empty string as UTF-16 null terminator
                    return Ok(Some(vec![0u8, 0u8]));
                }
                let s = value
                    .downcast::<PyStr>()
                    .map_err(|_| vm.new_type_error("value must be a string"))?;
                let wide = s.as_wtf8().to_wide_with_nul();
                // Convert Vec<u16> to Vec<u8>
                let bytes: Vec<u8> = wide.iter().flat_map(|&c| c.to_le_bytes()).collect();
                Ok(Some(bytes))
            }
            REG_MULTI_SZ => {
                if vm.is_none(&value) {
                    // Empty list = double null terminator
                    return Ok(Some(vec![0u8, 0u8, 0u8, 0u8]));
                }
                let list = value
                    .downcast::<crate::builtins::PyList>()
                    .map_err(|_| vm.new_type_error("value must be a list of strings"))?;