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use regex::Regex;
use lazy_static::lazy_static;
use std::error::Error;
use std::path::Path;
use std::fs::File;
use std::io;
use std::io::{BufRead, BufReader};
lazy_static! {
// Extract the sequence number "000017" from a string like this "A000017: Erroneous version of A032522.".
static ref EXTRACT_SEQUENCE_NUMBER: Regex = Regex::new(
"^A(\\d+):"
).unwrap();
}
fn parse_line(line: &String) -> Option<u32> {
if !line.starts_with("A") {
return None;
}
let re = &EXTRACT_SEQUENCE_NUMBER;
let captures = match re.captures(&line) {
Some(value) => value,
None => {
debug!("Unable to extract sequence number");
return None;
}
};
let capture1: &str = captures.get(1).map_or("", |m| m.as_str());
let sequence_number_string: String = capture1.to_string();
let sequence_number: u32 = match sequence_number_string.parse() {
Ok(value) => value,
_ => {
debug!("Unable to parse sequence number as u32");
return None;
}
};
return Some(sequence_number);
}
pub fn load_program_ids_from_deny_file(path: &Path) -> Result<Vec<u32>, Box<dyn Error>> {
let file = File::open(path)?;
let mut reader = BufReader::new(file);
load_program_ids_from_deny_file_inner(
&mut reader,
)
}
fn load_program_ids_from_deny_file_inner(
reader: &mut dyn io::BufRead
) -> Result<Vec<u32>, Box<dyn Error>> {
let mut program_ids: Vec<u32> = vec!();
let mut current_line_number: u32 = 0;
for line in reader.lines() {
current_line_number += 1;
let line: String = match line {
Ok(value) => value,
Err(error) => {
error!("Problem reading line #{:?}. {:?}", current_line_number, error);
continue;
}
};
let program_id: u32 = match parse_line(&line) {
Some(value) => value,
None => {
error!("Unable to parse line #{:?}. Skipping.", current_line_number);
continue;
}
};
program_ids.push(program_id);
}
Ok(program_ids)
}
#[cfg(test)]
mod tests {
use super::*;
fn parse(input: &str) -> String {
match parse_line(&input.to_string()) {
Some(program_id) => return program_id.to_string(),
None => return "NONE".to_string()
}
}
#[test]
fn test_10000_parse() {
assert_eq!(parse(""), "NONE");
assert_eq!(parse("\n"), "NONE");
assert_eq!(parse("# comment"), "NONE");
assert_eq!(parse("Ajunk"), "NONE");
assert_eq!(parse("A junk"), "NONE");
assert_eq!(parse("A000017: Erroneous version of A032522."), "17");
assert_eq!(parse("A000154: Erroneous version of A003713."), "154");
}
const INPUT_DATA: &str = r#"
A000017: Erroneous version of A032522.
A000154: Erroneous version of A003713.
Ajunk 123 ignore this line
Ignore this line as well
A000381: Essentially the same as A001611.
A000480: a(n) = floor(cos(n)).
A000572: A Beatty sequence: [ n(e+1) ].
"#;
#[test]
fn test_10001_parse_multiple_lines() {
let mut input: &[u8] = INPUT_DATA.as_bytes();
let result: Vec<u32> = load_program_ids_from_deny_file_inner(&mut input).unwrap();
assert_eq!(vec![17, 154, 381, 480, 572], result);
}
}
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