Struct MediaSource 

pub struct MediaSource<R> { /* private fields */ }

MediaSource represents a media data source that can be parsed by MediaParser.

• Use MediaSource::open to create a MediaSource from a file path.

• Use MediaSource::from_bytes for zero-copy in-memory input (Vec<u8>, &'static [u8], bytes::Bytes, …). Pair with MediaParser::parse_exif_from_bytes / MediaParser::parse_track_from_bytes.

• In other cases:

  • Use MediaSource::seekable to create a MediaSource from a Read + Seek (an already-open File goes here).

  • Use MediaSource::unseekable to create a MediaSource from a reader that only impl Read

Note: Please use MediaSource::seekable in preference to MediaSource::unseekable, since the former is more efficient when the parser needs to skip a large number of bytes.

Passing in a BufRead should be avoided because MediaParser comes with its own buffer management and the buffers can be shared between multiple parsing tasks, thus avoiding frequent memory allocations.

Implementations

impl<R> MediaSource<R>

pub fn kind(&self) -> MediaKind

Top-level classification of this media source.

impl<R: Read> MediaSource<R>

pub fn unseekable(reader: R) -> Result<Self>

Use MediaSource::unseekable to create a MediaSource from a reader that only impl Read

Note: Please use MediaSource::seekable in preference to MediaSource::unseekable, since the former is more efficient when the parser needs to skip a large number of bytes.

impl<R: Read + Seek> MediaSource<R>

pub fn seekable(reader: R) -> Result<Self>

Use MediaSource::seekable to create a MediaSource from a Read + Seek

Note: Please use MediaSource::seekable in preference to MediaSource::unseekable, since the former is more efficient when the parser needs to skip a large number of bytes.

impl MediaSource<File>

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

Open a file at path and parse its header to detect the media format.

This is the v3-preferred entry point for the common case of “I have a path on disk”. For an already-open File use Self::seekable.

impl MediaSource<()>

pub fn from_bytes(bytes: impl Into<Bytes>) -> Result<Self>

Build a MediaSource from an in-memory byte payload.

Accepts any type convertible into bytes::Bytes — Bytes, Vec<u8>, &'static [u8], bytes::Bytes::from_owner outputs, and HTTP-stack body types that implement Into<Bytes> directly.

The header (first up to 128 bytes) is sniffed for media kind, the same way MediaSource::open does it for files. The full payload is stored zero-copy: subsequent parsing through MediaParser::parse_exif_from_bytes / MediaParser::parse_track_from_bytes shares this Bytes directly with the returned ExifIter / sub-IFDs via reference counting.

The returned source is parsed by the dedicated MediaParser::parse_exif_from_bytes / MediaParser::parse_track_from_bytes methods. The streaming parse_exif / parse_track methods do not accept MediaSource<()> (their R: Read bound is unsatisfiable).

Example

use nom_exif::{MediaSource, MediaParser, MediaKind};

let bytes = std::fs::read("./testdata/exif.jpg")?;
let ms = MediaSource::from_bytes(bytes)?;
assert_eq!(ms.kind(), MediaKind::Image);

let mut parser = MediaParser::new();
let _iter = parser.parse_exif_from_bytes(ms)?;

Trait Implementations

impl<R> Debug for MediaSource<R>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.