# marshal.rs - source
Source of the Rust file `/home/runner/.cargo/registry/src/github.com-1ecc6299db9ec823/pyo3-0.13.2/src/marshal.rs`.
Keywords: rust, rustlang, rust-lang

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    #![cfg(not(Py_LIMITED_API))]
    //! Support for the Python `marshal` format. Not supported in limited API
    //! builds.

    use crate::ffi;
    use crate::types::{PyAny, PyBytes};
    use crate::{AsPyPointer, FromPyPointer, PyResult, Python};
    use std::os::raw::{c_char, c_int};

    /// The current version of the marshal binary format.
    pub const VERSION: i32 = 4;

    /// Serialize an object to bytes using the Python built-in marshal module.
    ///
    /// The built-in marshalling only supports a limited range of objects.
    /// The exact types supported depend on the version argument.
    /// The [`VERSION`] constant holds the highest version currently supported.
    ///
    /// See the [Python documentation](https://docs.python.org/3/library/marshal.html) for more details.
    ///
    /// # Example:
    /// ```
    /// # use pyo3::{marshal, types::PyDict};
    /// # let gil = pyo3::Python::acquire_gil();
    /// # let py = gil.python();
    /// #
    /// let dict = PyDict::new(py);
    /// dict.set_item("aap", "noot").unwrap();
    /// dict.set_item("mies", "wim").unwrap();
    /// dict.set_item("zus", "jet").unwrap();
    ///
    /// let bytes = marshal::dumps(py, dict, marshal::VERSION);
    /// ```
    pub fn dumps<'a>(py: Python<'a>, object: &impl AsPyPointer, version: i32) -> PyResult<&'a PyBytes> {
        unsafe {
            let bytes = ffi::PyMarshal_WriteObjectToString(object.as_ptr(), version as c_int);
            FromPyPointer::from_owned_ptr_or_err(py, bytes)
        }
    }

    /// Deserialize an object from bytes using the Python built-in marshal module.
    pub fn loads<'a, B>(py: Python<'a>, data: &B) -> PyResult<&'a PyAny>
    where
        B: AsRef<[u8]> + ?Sized,
    {
        let data = data.as_ref();
        unsafe {
            let c_str = data.as_ptr() as *const c_char;
            let object = ffi::PyMarshal_ReadObjectFromString(c_str, data.len() as isize);
            FromPyPointer::from_owned_ptr_or_err(py, object)
        }
    }

    #[cfg(test)]
    mod test {
        use super::*;
        use crate::types::PyDict;

        #[test]
        fn marhshal_roundtrip() {
            let gil = Python::acquire_gil();
            let py = gil.python();

            let dict = PyDict::new(py);
            dict.set_item("aap", "noot").unwrap();
            dict.set_item("mies", "wim").unwrap();
            dict.set_item("zus", "jet").unwrap();

            let bytes = dumps(py, dict, VERSION)
                .expect("marshalling failed")
                .as_bytes();
            let deserialzed = loads(py, bytes).expect("unmarshalling failed");

            assert!(equal(py, dict, deserialzed));
        }

        fn equal(_py: Python, a: &impl AsPyPointer, b: &impl AsPyPointer) -> bool {
            unsafe { ffi::PyObject_RichCompareBool(a.as_ptr(), b.as_ptr(), ffi::Py_EQ) != 0 }
        }
    }