file_rw

file_rw is a Rust crate for high-performance, memory-mapped file I/O utilities.

Features

• High-performance file reading and writing capabilities
• Memory-mapped files for efficient access and manipulation
• High-level, efficient abstractions of common operations on file contents

Installation

You can include the crate in your Rust project by either:

• Adding the following to your Cargo.toml file:

[dependencies]
file_rw = "0.6.6"

• Running the following Cargo command to automatically do so:

cargo add file_rw

Modules

• file: File operations
• read: File reading capabilities
• write: File writing capabilities

Re-exports

The crate re-exports the FileReader and FileWriter structs for external use. These structs contain the aforementioned utilities.

Examples

The following are examples of using methods from the FileReader and FileWriter structs. The examples are separated based on the crate features required to run them.

Simple Read and Write

use file_rw::{FileReader, FileWriter};
use tempfile::tempdir;

let tempdir = tempdir().unwrap();
let tempdir_path = tempdir.path();
let test_path = tempdir_path.join("test.txt");
let mut writer = FileWriter::open(&test_path).unwrap();

writer.append("Hello World!");
assert_eq!(writer.bytes(), b"Hello World!");

writer.overwrite("Hello");
assert_eq!(writer.bytes(), b"Hello");

writer.write("Hullo");
assert_eq!(writer.bytes(), b"Hullo");

Search and Replace

Use the search feature to enable search and replace capabilities.

use file_rw::{FileReader, FileWriter};
use tempfile::tempdir;

let tempdir = tempdir().unwrap();
let tempdir_path = tempdir.path();
let test_path = tempdir_path.join("test.txt");
let mut writer = FileWriter::open(&test_path).unwrap();
writer.overwrite("Hullo");

#[cfg(feature = "search")]
{
writer.find_replace_nth("l", "y", 0).unwrap();
assert_eq!(writer.bytes(), b"Huylo");

writer.find_replace("u", "e").unwrap();
assert_eq!(writer.bytes(), b"Heylo");

writer.find_replace("lo", "yyy").unwrap();
assert_eq!(writer.bytes(), b"Heyyyy");

writer.find_replace_all("y", "i").unwrap();
assert_eq!(writer.bytes(), b"Heiiii");

writer.find_replace("e", "i").unwrap();
assert_eq!(writer.bytes(), b"Hiiiii");

let reader = writer.as_reader().unwrap();
let content = reader.read_to_string();
assert_eq!(content, "Hiiiii");
}

Hashing

Use the hash feature to enable hash capabilities - these methods require providing a Digest to hash with.

use file_rw::{FileReader, FileWriter};
use tempfile::tempdir;

let tempdir = tempdir().unwrap();
let tempdir_path = tempdir.path();
let test_path = tempdir_path.join("test.txt");
let mut writer = FileWriter::open(&test_path).unwrap();

writer.overwrite("Hello World!");
let reader = writer.as_reader().unwrap();

#[cfg(feature = "hash")]
{
  assert_eq!(reader.hash_to_string_with::<sha3::Sha3_256>(), "d0e47486bbf4c16acac26f8b653592973c1362909f90262877089f9c8a4536af");
  
  use sha3::Digest;
  let mut sha3_direct_hasher = sha3::Sha3_256::new();
  sha3_direct_hasher.update(b"Hello World!");
  assert_eq!(reader.hash_with::<sha3::Sha3_256>(), sha3_direct_hasher.finalize());

}

SHA3_256 Hashing

Use the sha3_256 feature to enable SHA3_256 hash capabilities - this also enables the hash feature, but provides convenience methods that don't require manually providing a Digest.

use file_rw::{FileReader, FileWriter};
use tempfile::tempdir;

let tempdir = tempdir().unwrap();
let tempdir_path = tempdir.path();
let test_path = tempdir_path.join("test.txt");
let mut writer = FileWriter::open(&test_path).unwrap();

writer.overwrite("Hello World!");
let reader = writer.as_reader().unwrap();

#[cfg(feature = "sha3_256")]
{
  assert_eq!(reader.hash_to_string(), "d0e47486bbf4c16acac26f8b653592973c1362909f90262877089f9c8a4536af");
  
  use sha3::Digest;
  let mut sha3_direct_hasher = sha3::Sha3_256::new();
  sha3_direct_hasher.update(b"Hello World!");
  assert_eq!(reader.hash(), sha3_direct_hasher.finalize());
}