Crate rabuf

The Buffer for random access file.

When you read and write a file, this read and write in Chunk units and reduce IO operation.

Features

• random access
• Chunk units os io operation
• reduce os io operation
• support small size access accel.
• minimum support rustc 1.56.1 (59eed8a2a 2021-11-01)

Examples

Write, Seek, Read

use rabuf::BufFile;
use std::fs::OpenOptions;
use std::io::{Read, Seek, SeekFrom, Write};

std::fs::create_dir_all("target/tmp").unwrap();

let path = "target/tmp/doc_test_1";
let bw = b"ABCEDFG\nhijklmn\n";

let f = OpenOptions::new().create(true)
    .read(true).write(true).open(path).unwrap();
let mut bf = BufFile::new("tes", f).unwrap();
bf.write_all(bw).unwrap();

bf.seek(SeekFrom::Start(0)).unwrap();

let mut br = vec![0u8; bw.len()];
bf.read_exact(&mut br).unwrap();
assert_eq!(&br, bw);

Write, Close, Open, Read

use rabuf::BufFile;
use std::fs::OpenOptions;
use std::io::{Read, Seek, SeekFrom, Write};

std::fs::create_dir_all("target/tmp").unwrap();
let path = "target/tmp/doc_test_2";

let bw = b"abcdefg\nHIJKLMN\n";
{
    let f = OpenOptions::new().create(true)
        .read(true).write(true).open(path).unwrap();
    let mut bf = BufFile::new("tes", f).unwrap();
    bf.write_all(bw).unwrap();
}
{
    let f = OpenOptions::new().create(true)
        .read(true).write(true).open(path).unwrap();
    let mut bf = BufFile::new("tes", f).unwrap();
    let mut br = vec![0u8; bw.len()];
    bf.read_exact(&mut br).unwrap();
    assert_eq!(&br, bw);
}

Re-exports

• pub use maybe::MaybeSlice;

Modules

• maybe

Structs

• RaBuf
  Generic random access buffer.

Traits

• FileSetLen
  Truncates or extends the underlying file.
• FileSync
  File syncronization include OS-internal metadata to disk.
• SmallRead
  Read small bytes less than chunk size.
• SmallWrite
  Write small bytes less than chunk size.

Functions

• roundup_powerof2
  Round up power of 2.

Type Aliases

• BufFile
  Buffered File for ramdom access.