Struct lofty::Probe

pub struct Probe<R: Read> { /* private fields */ }

A format agnostic reader

This provides a way to determine the FileType of a reader, for when a concrete type is not known.

Usage

When reading from a path, the FileType will be inferred from the path, rather than the open file.

use lofty::FileType;

let probe = Probe::open("tests/files/assets/minimal/full_test.mp3")?;

// Inferred from the `mp3` extension
assert_eq!(probe.file_type(), Some(FileType::MP3));

When a path isn’t available, or is unreliable, content-based detection is also possible.

use lofty::FileType;

// Our same path probe with a guessed file type
let probe = Probe::open("tests/files/assets/minimal/full_test.mp3")?.guess_file_type()?;

// Inferred from the file's content
assert_eq!(probe.file_type(), Some(FileType::MP3));

Or with another reader

use lofty::FileType;
use std::io::Cursor;

static MAC_HEADER: &[u8; 3] = b"MAC";

let probe = Probe::new(Cursor::new(MAC_HEADER)).guess_file_type()?;

// Inferred from the MAC header
assert_eq!(probe.file_type(), Some(FileType::APE));

Implementations

impl<R: Read> Probe<R>

pub fn new(reader: R) -> Self

Create a new Probe

pub fn with_file_type(reader: R, file_type: FileType) -> Self

Create a new Probe with a specified FileType

pub fn file_type(&self) -> Option<FileType>

Returns the current FileType

pub fn set_file_type(&mut self, file_type: FileType)

Set the FileType with which to read the file

pub fn into_inner(self) -> R

Extract the reader

impl Probe<BufReader<File>>

pub fn open<P>(path: P) -> Result<Self> where
    P: AsRef<Path>, 

Opens a file for reading

This will initially guess the FileType from the path, but this can be overwritten with Probe::guess_file_type or Probe::set_file_type

Errors

• path does not exist

impl<R: Read + Seek> Probe<R>

pub fn guess_file_type(self) -> Result<Self>

Attempts to get the FileType based on the data in the reader

On success, the file type will be replaced

Errors

All errors that occur within this function are std::io::Error. If an error does occur, there is likely an issue with the provided reader, and the entire Probe should be discarded.

pub fn read(self, read_properties: bool) -> Result<TaggedFile>

Attempts to extract a TaggedFile from the reader

If read_properties is false, the properties will be zeroed out.

Errors

• No file type
  • This expects the file type to have been set already, either with Probe::guess_file_type or Probe::set_file_type. When reading from paths, this is not necessary.
• The reader contains invalid data