Detect and open unknown images

Use category facades when the input format is not known in advance. Detection is non-destructive: it restores the stream position after examining identifying metadata. Opening performs the format's full validation.

Block images

[dependencies]
hadris-block = "2.1.0"

use hadris_block::{detect, sync::OpenVolume};
use std::fs::File;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut image = File::open("disk.img")?;
    let format = detect::sync::detect(&mut image, 512)?;
    println!("detected: {format:?}");

    match format {
        Some(detect::BlockFormat::Fat(_)) => {
            let opened = OpenVolume::open(&mut image, 512)?;
            let fat = opened.as_fat().expect("the detector reported FAT");
            println!("FAT variant: {}", fat.fat_type());
        }
        Some(detect::BlockFormat::PartitionTable(kind)) => {
            println!("partitioned disk: {kind:?}");
        }
        None => println!("no supported block format detected"),
    }

    Ok(())
}

OpenVolume intentionally refuses a whole partitioned disk. Select a partition and create a bounded view before opening its filesystem.

Optical images

[dependencies]
hadris-optical = "2.1.0"

use hadris_optical::{OpenPolicy, sync::OpenOpticalImage};
use std::fs::File;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut image = File::open("disc.img")?;
    let opened = OpenOpticalImage::open(&mut image, OpenPolicy::PreferUdf)?;

    if let Some(udf) = opened.as_udf() {
        println!("UDF volume: {}", udf.info().volume_id);
    } else if opened.as_iso9660().is_some() {
        println!("ISO 9660 image");
    }

    Ok(())
}

Bridge images can contain valid ISO 9660 and UDF filesystems simultaneously. Use PreferUdf or PreferIso9660 for fallback behavior, and Udf or Iso9660 when the requested format is mandatory.

Detection is not validation

Detection answers “what does this look like?” using signatures and geometry. Always open the returned concrete format before trusting offsets, sizes, or directory data. Treat None as an unknown format rather than as proof that the input is unformatted.