FileIO

Fluent file operations in Rust: read, write, append, replace, insert, and manipulate lines with a simple API.

Features

• Reading
  • .read_all() → Read entire file as a String
  • .read_lines() → Read file line by line (Vec<String>)
  • .read_non_empty_lines() → Read non-empty trimmed lines
  • .read_range(start, end) → Read a 1-based inclusive range of lines
  • .count_lines() → Count lines efficiently
• Writing
  • .write(content) → Overwrite the whole file
  • .write_lines(iter) → Overwrite with many lines
  • .append(content) → Append a line at the end
  • .append_lines(iter) → Append multiple lines
  • .write_line(n, content) → Replace a specific line (1-based)
  • .insert_line(n, content) → Insert a line without overwriting
  • .insert_lines(n, iter) → Insert multiple lines at a position
  • .remove_line(n) / .remove_lines(start, end) → Remove one or many lines
  • .find_replace(find, replace) → Replace all occurrences in the whole file
• Utilities
  • .exists() → Check if file exists
  • .create_if_missing() → Create an empty file if it doesn’t exist
  • .is_empty() → Whether the file is empty or missing
  • file(path) → Convenience constructor

Under the hood, BufReader/BufWriter are used for good performance, and PathBuf is used for path robustness. Backwards compatibility is kept.

Installation

Add to your Cargo.toml:

[dependencies]
fileio = ">=0.2.0"

Quick start

use fileio::file;

fn main() -> std::io::Result<()> {
    let f = file("src/example.txt");
    f.create_if_missing()?;

    // Overwrite with fresh content
    f.write_lines(["alpha", "beta", "gamma"])?;

    // Insert and update lines (1-based)
    f.insert_line(1, "start")?;
    f.write_line(3, "BETA")?;

    // Append more
    f.append_lines(["delta", "epsilon"])?;

    // Read a range and print
    let first_three = f.read_range(1, 3)?;
    println!("first_three: {:?}", first_three);

    Ok(())
}

Examples

See src/main.rs for a more comprehensive example demonstrating inserts, deletes, find/replace, and counts.

Safety and portability

• Uses a relative path in examples so it works on any machine.
• Validates line numbers are 1-based and returns clear InvalidInput errors.
• Missing files are handled gracefully with helpers like .create_if_missing() and .is_empty().