tsfile 0.0.2

Apache IoTDB TsFile written in Rust
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81

use crate::utils::cursor;
use crate::utils::cursor::PackWidthReader;
use byteorder::{BigEndian, ReadBytesExt};
use snafu::{ResultExt, Snafu};
use std::io::Cursor;

#[derive(Debug, Snafu)]
pub enum Error {
    #[snafu(display("Unable to read cursor data: {}", source))]
    ReadCursorData { source: std::io::Error },
    #[snafu(display("Unable to read packed data: {}", source))]
    ReadPackedData { source: cursor::Error },
}

type Result<T, E = Error> = std::result::Result<T, E>;

#[derive(Debug)]
pub enum Field {
    Boolean(bool),
    Int32(i32),
    Int64(i64),
    FLOAT(f32),
    DOUBLE(f64),
    TEXT(Vec<u8>),
}

pub trait Decoder {
    fn new() -> Self
    where
        Self: Sized;
    fn decode(&self, data: &mut Cursor<Vec<u8>>) -> Result<Vec<Field>>;
}

pub trait BinaryDelta: Decoder {}

pub struct LongBinaryDecoder {}

impl Decoder for LongBinaryDecoder {
    fn new() -> Self {
        Self {}
    }

    fn decode(&self, data: &mut Cursor<Vec<u8>>) -> Result<Vec<Field>> {
        let pack_num = data.read_i32::<BigEndian>().context(ReadCursorData)?;
        let pack_width = data.read_i32::<BigEndian>().context(ReadCursorData)?;
        let min_delta_base = data.read_i64::<BigEndian>().context(ReadCursorData)?;
        let mut previous = data.read_i64::<BigEndian>().context(ReadCursorData)?;
        let mut result = Vec::with_capacity(pack_num as usize);

        for i in 0..pack_num {
            let value = data
                .read_pack_width_long(pack_width * i, pack_width)
                .context(ReadPackedData)?;
            previous = previous + min_delta_base + value;
            result.push(Field::Int64(previous));
        }

        Ok(result)
    }
}

pub trait PlainDecoder: Decoder {}

pub struct IntPlainDecoder {}

impl Decoder for IntPlainDecoder {
    fn new() -> Self {
        Self {}
    }

    fn decode(&self, data: &mut Cursor<Vec<u8>>) -> Result<Vec<Field>> {
        let mut result = Vec::new();
        while data.position() < data.get_ref().len() as u64 {
            result.push(Field::Int32(
                data.read_i32::<BigEndian>().context(ReadCursorData)?,
            ));
        }

        Ok(result)
    }
}