Function try_decode_code_page_strict

crates/vm/src/stdlib/_codecs.rs:1094–1145

Try to decode the entire buffer with strict flags (fast path). Returns Ok(Some(wide_chars)) on success, Ok(None) on decode error, or Err on OS error.

(
        code_page: u32,
        data: &[u8],
        vm: &VirtualMachine,
    )

    /// Returns Ok(Some(wide_chars)) on success, Ok(None) on decode error,
    /// or Err on OS error.
    fn try_decode_code_page_strict(
        code_page: u32,
        data: &[u8],
        vm: &VirtualMachine,
    ) -> PyResult<Option<Vec<u16>>> {
        use windows_sys::Win32::Globalization::{MB_ERR_INVALID_CHARS, MultiByteToWideChar};

        let mut flags = MB_ERR_INVALID_CHARS;

        loop {
            let size = unsafe {
                MultiByteToWideChar(
                    code_page,
                    flags,
                    data.as_ptr().cast(),
                    data.len() as i32,
                    core::ptr::null_mut(),
                    0,
                )
            };
            if size > 0 {
                let mut buffer = vec![0u16; size as usize];
                let result = unsafe {
                    MultiByteToWideChar(
                        code_page,
                        flags,
                        data.as_ptr().cast(),
                        data.len() as i32,
                        buffer.as_mut_ptr(),
                        size,
                    )
                };
                if result > 0 {
                    buffer.truncate(result as usize);
                    return Ok(Some(buffer));
                }
            }

            let err_code = std::io::Error::last_os_error().raw_os_error().unwrap_or(0);
            // ERROR_INVALID_FLAGS = 1004
            if flags != 0 && err_code == 1004 {
                flags = 0;
                continue;
            }
            // ERROR_NO_UNICODE_TRANSLATION = 1113
            if err_code == 1113 {
                return Ok(None);
            }
            let err = std::io::Error::last_os_error();
            return Err(vm.new_os_error(format!("code_page_decode: {err}")));
        }
    }

    /// Decode byte by byte with error handling (slow path).
    fn decode_code_page_errors(