dsv 0.13.0

dsv (Data Swiss Knife) — a high-performance CSV, Parquet, and JSONL CLI toolkit. Modern xsv fork with all 33 community PRs merged.
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
82
83

use std::fs;

use crate::config::{Config, Delimiter};
use crate::index::Indexed;
use crate::util;
use crate::CliResult;
use clap::Parser;

#[derive(Parser, Debug)]
pub struct Args {
    #[arg()]
    pub arg_input: Option<String>,
    #[arg(short = 's', long = "start", value_name = "arg")]
    pub flag_start: Option<usize>,
    #[arg(short = 'e', long = "end", value_name = "arg")]
    pub flag_end: Option<usize>,
    #[arg(short = 'l', long = "len", value_name = "arg")]
    pub flag_len: Option<usize>,
    #[arg(short = 'i', long = "index", value_name = "arg")]
    pub flag_index: Option<usize>,
    #[arg(short = 'o', long = "output", value_name = "file")]
    pub flag_output: Option<String>,
    #[arg(short = 'n', long = "no-headers")]
    pub flag_no_headers: bool,
    #[arg(short = 'd', long = "delimiter", value_name = "arg")]
    pub flag_delimiter: Option<Delimiter>,
}

pub fn run(args: &Args) -> CliResult<()> {
    match args.rconfig().indexed()? {
        None => args.no_index(),
        Some(idxed) => args.with_index(idxed),
    }
}

impl Args {
    fn no_index(&self) -> CliResult<()> {
        let mut rdr = self.rconfig().reader()?;
        let mut wtr = self.wconfig().writer()?;
        self.rconfig().write_headers(&mut rdr, &mut wtr)?;

        let (start, end) = self.range()?;
        for r in rdr.byte_records().skip(start).take(end - start) {
            wtr.write_byte_record(&r?)?;
        }
        Ok(wtr.flush()?)
    }

    fn with_index(&self, mut idx: Indexed<fs::File, fs::File>) -> CliResult<()> {
        let mut wtr = self.wconfig().writer()?;
        self.rconfig().write_headers(&mut *idx, &mut wtr)?;

        let (start, end) = self.range()?;
        if end - start == 0 {
            return Ok(());
        }
        idx.seek(start as u64)?;
        for r in idx.byte_records().take(end - start) {
            wtr.write_byte_record(&r?)?;
        }
        wtr.flush()?;
        Ok(())
    }

    fn range(&self) -> Result<(usize, usize), String> {
        util::range(
            self.flag_start,
            self.flag_end,
            self.flag_len,
            self.flag_index,
        )
    }

    fn rconfig(&self) -> Config {
        Config::new(&self.arg_input)
            .delimiter(self.flag_delimiter)
            .no_headers(self.flag_no_headers)
    }

    fn wconfig(&self) -> Config {
        Config::new(&self.flag_output)
    }
}