iterate_text/file/
lines.rs

1#!/usr/bin/env rust
2
3
4//! Reads from file path, buffer, or descriptor and iterates over lines until EOF is reached
5//!
6//! # Example
7//!
8//! ```rust
9//! use iterate_text::file::lines::IterateFileLines;
10//!
11//! let p = "tests/file/lines/file.txt";
12//! let mut l = IterateFileLines::new(p);
13//!
14//! assert_eq!(l.next(), Some("First line\n".to_string()));
15//! assert_eq!(l.next(), Some("Second line\n".to_string()));
16//! assert_eq!(l.next(), Some("Third line\n".to_string()));
17//! assert_eq!(l.next(), None);
18//! ```
19
20
21use std::io::BufReader;
22use std::io::BufRead;
23use std::fs::File;
24
25
26/// Wraps `BufReader<File>` and wraps `.read_line()` from `BufReader` as an Iterator
27#[derive(Debug)]
28pub struct IterateFileLines {
29    file_buffer: BufReader<File>,
30}
31
32
33impl IterateFileLines {
34    /// Initializes structure with `BufReader` for file `path`
35    pub fn new<S: Into<String>>(path: S) -> Self {
36        let file_descriptor = File::open(path.into()).unwrap();
37        let file_buffer = BufReader::new(file_descriptor);
38        Self { file_buffer }
39    }
40}
41
42
43impl Iterator for IterateFileLines {
44    type Item = String;
45
46    /// Returns `Option<String>` when a line is available from `.read_line()` or `None` when EOF is
47    /// reached.
48    fn next(&mut self) -> Option<Self::Item> {
49        let mut line = String::new();
50        match self.file_buffer.read_line(&mut line) {
51            Ok(state) => match state {
52                0 => None,
53                _ => Some(line),
54            },
55            _ => None,
56        }
57    }
58}
59
60
61impl From<File> for IterateFileLines {
62    /// Initializes structure from `File` descriptor
63    fn from (file_descriptor: File) -> Self {
64        Self { file_buffer: BufReader::new(file_descriptor) }
65    }
66}
67
68impl From<BufReader<File>> for IterateFileLines {
69    /// Initializes structure from `BufReader<File>`
70    fn from(buffer_reader: BufReader<File>) -> Self {
71        Self { file_buffer: buffer_reader }
72    }
73}
74
iterate_text/file/lines.rs

iterate_text/file/
lines.rs
