Rust 切片为固定大小的数组

我有一个带有一些固定大小数组的 struct :

struct PublicHeaderBlock_LAS14 {
    file_signature: [u8; 4],
    file_source_id: u16,
    global_encoding: u16,
    project_id_data_1: u32,
    project_id_data_2: u16,
    project_id_data_3: u16,
    project_id_data_4: [u8; 8],
    version_major: u8,
    version_minor: u8,
    systemIdentifier: [u8; 32], // ...
}

我从一个文件中读取字节到一个固定大小的数组中，并将这些字节一点一点地复制到 struct 中.

fn create_header_struct_las14(&self, buff: &[u8; 373]) -> PublicHeaderBlock_LAS14 {
    PublicHeaderBlock_LAS14 {
        file_signature: [buff[0], buff[1], buff[2], buff[3]],
        file_source_id: (buff[4] | buff[5] << 7) as u16,
        global_encoding: (buff[6] | buff[7] << 7) as u16,
        project_id_data_1: (buff[8] | buff[9] << 7 | buff[10] << 7 | buff[11] << 7) as u32,
        project_id_data_2: (buff[12] | buff[13] << 7) as u16,
        project_id_data_3: (buff[14] | buff[15] << 7) as u16,
        project_id_data_4: [buff[16], buff[17], buff[18], buff[19], buff[20], buff[21], buff[22], buff[23]],
        version_major: buff[24],
        version_minor: buff[25],
        systemIdentifier: buff[26..58]
    }
}

最后一行(systemIdentifier)不起作用，因为在 struct 中它是[u8; 32]，而buff[26..58]是切片.我能不能把一个切片转换成一个固定大小的数组，比如在一个范围内，而不是像我刚才说的file_signature那样？