Struct seq_data_file::SeqDataReaderSeek

pub struct SeqDataReaderSeek<Format: SeqDataFormat> { /* private fields */ }

Seq Data Reader with seek

Implementations

impl<Format: SeqDataFormat> SeqDataReaderSeek<Format>

pub fn open<P: AsRef<Path>>(path: P) -> Result<(Self, Vec<u8>)>

Open a new Seq Data seeker

Examples found in repository

examples/run.rs (line 73)

fn run_writer_reader<H: SeqDataFormat>(sdf_file: &Path) {
    {
        let header = vec![0x90; H::HEADER_SIZE];
        let mut sdf = SeqDataWriter::<H>::create(&sdf_file, &header).unwrap();
        sdf.append(DATA1).unwrap();
        sdf.append(DATA2).unwrap();
        sdf.append(DATA3).unwrap();
    }

    let mut pos = Vec::new();
    {
        let (mut sdf, _header) = SeqDataReader::<H>::open(&sdf_file).unwrap();
        let (p1, r1) = sdf.next().unwrap().unwrap();
        let (p2, r2) = sdf.next().unwrap().unwrap();
        let (p3, r3) = sdf.next().unwrap().unwrap();

        pos.push(p1);
        pos.push(p2);
        pos.push(p3);

        assert_eq!(p1, 0);
        assert_eq!(r1, DATA1);

        assert_eq!(p2, 4 + DATA1.len() as u64);
        assert_eq!(r2, DATA2);

        assert_eq!(p3, 4 * 2 + DATA1.len() as u64 + DATA2.len() as u64);
        assert_eq!(r3, DATA3);

        if let Some(x) = sdf.next() {
            panic!("more data than expected {:?}", x)
        }
    }

    {
        let (mut sdf, _header) = SeqDataReaderSeek::<H>::open(sdf_file).unwrap();
        let r2 = sdf.next_at(pos[1]).unwrap();
        assert_eq!(r2, DATA2);
        let r1 = sdf.next_at(pos[0]).unwrap();
        assert_eq!(r1, DATA1);
        let r3 = sdf.next_at(pos[2]).unwrap();
        assert_eq!(r3, DATA3);
    }
}

pub fn next(&mut self) -> Result<Vec<u8>>

Return the next block along with the current offset if it exists, or None if reached the end of file.

pub fn next_at(&mut self, pos: u64) -> Result<Vec<u8>>

Return the next block at the offset specified

Note that if the position specified is not a valid boundary, then arbitrary invalid stuff might be returns, or some Err related to reading data

Examples found in repository

examples/run.rs (line 74)

fn run_writer_reader<H: SeqDataFormat>(sdf_file: &Path) {
    {
        let header = vec![0x90; H::HEADER_SIZE];
        let mut sdf = SeqDataWriter::<H>::create(&sdf_file, &header).unwrap();
        sdf.append(DATA1).unwrap();
        sdf.append(DATA2).unwrap();
        sdf.append(DATA3).unwrap();
    }

    let mut pos = Vec::new();
    {
        let (mut sdf, _header) = SeqDataReader::<H>::open(&sdf_file).unwrap();
        let (p1, r1) = sdf.next().unwrap().unwrap();
        let (p2, r2) = sdf.next().unwrap().unwrap();
        let (p3, r3) = sdf.next().unwrap().unwrap();

        pos.push(p1);
        pos.push(p2);
        pos.push(p3);

        assert_eq!(p1, 0);
        assert_eq!(r1, DATA1);

        assert_eq!(p2, 4 + DATA1.len() as u64);
        assert_eq!(r2, DATA2);

        assert_eq!(p3, 4 * 2 + DATA1.len() as u64 + DATA2.len() as u64);
        assert_eq!(r3, DATA3);

        if let Some(x) = sdf.next() {
            panic!("more data than expected {:?}", x)
        }
    }

    {
        let (mut sdf, _header) = SeqDataReaderSeek::<H>::open(sdf_file).unwrap();
        let r2 = sdf.next_at(pos[1]).unwrap();
        assert_eq!(r2, DATA2);
        let r1 = sdf.next_at(pos[0]).unwrap();
        assert_eq!(r1, DATA1);
        let r3 = sdf.next_at(pos[2]).unwrap();
        assert_eq!(r3, DATA3);
    }
}