Struct SeqDataReaderSeek

Source

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

Expand description

Seq Data Reader with seek

Implementations§

Source §

impl<Format: SeqDataFormat> SeqDataReaderSeek<Format>

Source

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)

38fn run_writer_reader<H: SeqDataFormat>(sdf_file: &Path) {
39    {
40        let header = vec![0x90; H::HEADER_SIZE];
41        let mut sdf = SeqDataWriter::<H>::create(&sdf_file, &header).unwrap();
42        sdf.append(DATA1).unwrap();
43        sdf.append(DATA2).unwrap();
44        sdf.append(DATA3).unwrap();
45    }
46
47    let mut pos = Vec::new();
48    {
49        let (mut sdf, _header) = SeqDataReader::<H>::open(&sdf_file).unwrap();
50        let (p1, r1) = sdf.next().unwrap().unwrap();
51        let (p2, r2) = sdf.next().unwrap().unwrap();
52        let (p3, r3) = sdf.next().unwrap().unwrap();
53
54        pos.push(p1);
55        pos.push(p2);
56        pos.push(p3);
57
58        assert_eq!(p1, 0);
59        assert_eq!(r1, DATA1);
60
61        assert_eq!(p2, 4 + DATA1.len() as u64);
62        assert_eq!(r2, DATA2);
63
64        assert_eq!(p3, 4 * 2 + DATA1.len() as u64 + DATA2.len() as u64);
65        assert_eq!(r3, DATA3);
66
67        if let Some(x) = sdf.next() {
68            panic!("more data than expected {:?}", x)
69        }
70    }
71
72    {
73        let (mut sdf, _header) = SeqDataReaderSeek::<H>::open(sdf_file).unwrap();
74        let r2 = sdf.next_at(pos[1]).unwrap();
75        assert_eq!(r2, DATA2);
76        let r1 = sdf.next_at(pos[0]).unwrap();
77        assert_eq!(r1, DATA1);
78        let r3 = sdf.next_at(pos[2]).unwrap();
79        assert_eq!(r3, DATA3);
80    }
81}

Source

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.

Source

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)

38fn run_writer_reader<H: SeqDataFormat>(sdf_file: &Path) {
39    {
40        let header = vec![0x90; H::HEADER_SIZE];
41        let mut sdf = SeqDataWriter::<H>::create(&sdf_file, &header).unwrap();
42        sdf.append(DATA1).unwrap();
43        sdf.append(DATA2).unwrap();
44        sdf.append(DATA3).unwrap();
45    }
46
47    let mut pos = Vec::new();
48    {
49        let (mut sdf, _header) = SeqDataReader::<H>::open(&sdf_file).unwrap();
50        let (p1, r1) = sdf.next().unwrap().unwrap();
51        let (p2, r2) = sdf.next().unwrap().unwrap();
52        let (p3, r3) = sdf.next().unwrap().unwrap();
53
54        pos.push(p1);
55        pos.push(p2);
56        pos.push(p3);
57
58        assert_eq!(p1, 0);
59        assert_eq!(r1, DATA1);
60
61        assert_eq!(p2, 4 + DATA1.len() as u64);
62        assert_eq!(r2, DATA2);
63
64        assert_eq!(p3, 4 * 2 + DATA1.len() as u64 + DATA2.len() as u64);
65        assert_eq!(r3, DATA3);
66
67        if let Some(x) = sdf.next() {
68            panic!("more data than expected {:?}", x)
69        }
70    }
71
72    {
73        let (mut sdf, _header) = SeqDataReaderSeek::<H>::open(sdf_file).unwrap();
74        let r2 = sdf.next_at(pos[1]).unwrap();
75        assert_eq!(r2, DATA2);
76        let r1 = sdf.next_at(pos[0]).unwrap();
77        assert_eq!(r1, DATA1);
78        let r3 = sdf.next_at(pos[2]).unwrap();
79        assert_eq!(r3, DATA3);
80    }
81}