Struct NumberReader

pub struct NumberReader<R: Read> { /* private fields */ }

A NumberReader wraps a reader and provides methods for reading numbers.

Unlike many libraries, which take byte order as a parameter per operation, a NumberReader takes byte order as a parameter upon initialization.

Examples

We can create a new NumberReader using the target endianness using NumberReader::new:

use std::io::Cursor;
use byte_order::NumberReader;

let src = Cursor::new(vec![]);
let mut reader = NumberReader::new(src);

Or, to read numbers with a certain endianness, we can create NumberReader structures using NumberReader::with_order:

use std::io::Cursor;
use byte_order::{ByteOrder, NumberReader};

let src = Cursor::new(vec![]);
let mut be_reader = NumberReader::with_order(ByteOrder::BE, src.clone());
let mut le_reader = NumberReader::with_order(ByteOrder::LE, src.clone());
let mut ne_reader = NumberReader::with_order(ByteOrder::NE, src.clone());

To read numbers from the underlying reader, use any of the read_* methods that are provided:

use std::io::Cursor;
use byte_order::{ByteOrder, NumberReader};

let src = Cursor::new(vec![0xA1, 0xB2]);

let mut be_reader = NumberReader::with_order(ByteOrder::BE, src.clone());
assert_eq!(0xA1B2, be_reader.read_u16()?);

let mut le_reader = NumberReader::with_order(ByteOrder::LE, src.clone());
assert_eq!(0xB2A1, le_reader.read_u16()?);

let mut ne_reader = NumberReader::with_order(ByteOrder::NE, src.clone());
assert_eq!(
    if cfg!(target_endian = "big") {
        0xA1B2
    } else {
        0xB2A1
    },
    ne_reader.read_u16()?
);

Implementations

impl<R: Read> NumberReader<R>

pub fn new(src: R) -> NumberReader<R>

Creates a new NumberReader by wrapping the given reader.

Since the target platform’s native endianness is used, portable code should use with_order, as appropriate, instead.

Note: If you want to explicitly mark in your code that the target platform’s endianness is desired, consider creating the NumberReader using with_order and ByteOrder::NE.

Examples

use std::io::{self, Cursor};
use byte_order::NumberReader;

fn main() -> io::Result<()> {
    let src = Cursor::new(vec![0xA1, 0xB2]);
    let mut reader = NumberReader::new(src);

    assert_eq!(
        reader.read_u16()?,
        if cfg!(target_endian = "big") {
            0xA1B2
        } else {
            0xB2A1
        }
    );

    Ok(())
}

pub fn with_order(order: ByteOrder, src: R) -> NumberReader<R>

Creates a new NumberReader by wrapping the given reader with the specified byte order.

Use either ByteOrder::BE for big-endian byte ordering, ByteOrder::LE for little-endian byte ordering, or ByteOrder::NE to explicitly use the target platform’s endianness.

Examples

use std::io::{self, Cursor};
use byte_order::{ByteOrder, NumberReader};

fn main() -> io::Result<()> {
    let src = Cursor::new(vec![0xA1, 0xB2]);

    let mut be_reader = NumberReader::with_order(ByteOrder::BE, src.clone());
    assert_eq!(0xA1B2, be_reader.read_u16()?);

    let mut le_reader = NumberReader::with_order(ByteOrder::LE, src.clone());
    assert_eq!(0xB2A1, le_reader.read_u16()?);

    let mut ne_reader = NumberReader::with_order(ByteOrder::NE, src.clone());
    assert_eq!(
        if cfg!(target_endian = "big") {
            0xA1B2
        } else {
            0xB2A1
        },
        ne_reader.read_u16()?
    );

    Ok(())
}

pub fn into_inner(self) -> R

Consumes this NumberReader, returning the underlying value.

Examples

use std::io::Cursor;
use byte_order::NumberReader;

let reader = NumberReader::new(Cursor::new(vec![]));

let cursor = reader.into_inner();

pub fn get_ref(&self) -> &R

Gets a reference to the underlying value in this NumberReader.

Examples

use std::io::Cursor;
use byte_order::NumberReader;

let reader = NumberReader::new(Cursor::new(vec![]));

let reference = reader.get_ref();

pub fn get_mut(&mut self) -> &mut R

Gets a mutable reference to the underlying value in this NumberReader.

Examples

use std::io::Cursor;
use byte_order::NumberReader;

let mut reader = NumberReader::new(Cursor::new(vec![]));

let reference = reader.get_mut();

pub fn read_u8(&mut self) -> Result<u8>

Reads an unsigned 8-bit integer from the underlying reader.

Note: Since this method reads a single byte, no byte order conversions are used. It is included for completeness.

Errors

This method propagates any error recieved from the internal call to Read::read_exact.

Examples

use std::io::{self, Cursor};
use byte_order::NumberReader;

fn main() -> io::Result<()> {
    let mut reader = NumberReader::new(Cursor::new(vec![0x12]));
    assert_eq!(0x12u8, reader.read_u8()?);
    Ok(())
}

pub fn read_i8(&mut self) -> Result<i8>

Reads a signed 8-bit integer from the underlying reader.

Note: Since this method reads a single byte, no byte order conversions are used. It is included for completeness.

Errors

This method propagates any error recieved from the internal call to Read::read_exact.

Examples

use std::io::{self, Cursor};
use byte_order::NumberReader;

fn main() -> io::Result<()> {
    let mut reader = NumberReader::new(Cursor::new(vec![0x12]));
    assert_eq!(0x12i8, reader.read_i8()?);
    Ok(())
}

pub fn read_u16(&mut self) -> Result<u16>

Reads an unsigned 16-bit integer from the underlying reader.

Errors

This method propagates any error recieved from the internal call to Read::read_exact.

Examples

use std::io::{self, Cursor};
use byte_order::{ByteOrder, NumberReader};

fn main() -> io::Result<()> {
    let src = Cursor::new(vec![0x12, 0x34]);

    let mut be_reader = NumberReader::with_order(ByteOrder::BE, src.clone());
    assert_eq!(0x1234u16, be_reader.read_u16()?);

    let mut le_reader = NumberReader::with_order(ByteOrder::LE, src.clone());
    assert_eq!(0x3412u16, le_reader.read_u16()?);

    Ok(())
}

pub fn read_i16(&mut self) -> Result<i16>

Reads a signed 16-bit integer from the underlying reader.

Errors

This method propagates any error recieved from the internal call to Read::read_exact.

Examples

use std::io::{self, Cursor};
use byte_order::{ByteOrder, NumberReader};

fn main() -> io::Result<()> {
    let src = Cursor::new(vec![0x12, 0x34]);

    let mut be_reader = NumberReader::with_order(ByteOrder::BE, src.clone());
    assert_eq!(0x1234i16, be_reader.read_i16()?);

    let mut le_reader = NumberReader::with_order(ByteOrder::LE, src.clone());
    assert_eq!(0x3412i16, le_reader.read_i16()?);

    Ok(())
}

pub fn read_u32(&mut self) -> Result<u32>

Reads an unsigned 32-bit integer from the underlying reader.

Errors

This method propagates any error recieved from the internal call to Read::read_exact.

Examples

use std::io::{self, Cursor};
use byte_order::{ByteOrder, NumberReader};

fn main() -> io::Result<()> {
    let src = Cursor::new(vec![0x12, 0x34, 0x56, 0x78]);

    let mut be_reader = NumberReader::with_order(ByteOrder::BE, src.clone());
    assert_eq!(0x12345678u32, be_reader.read_u32()?);

    let mut le_reader = NumberReader::with_order(ByteOrder::LE, src.clone());
    assert_eq!(0x78563412u32, le_reader.read_u32()?);

    Ok(())
}

pub fn read_i32(&mut self) -> Result<i32>

Reads a signed 32-bit integer from the underlying reader.

Errors

This method propagates any error recieved from the internal call to Read::read_exact.

Examples

use std::io::{self, Cursor};
use byte_order::{ByteOrder, NumberReader};

fn main() -> io::Result<()> {
    let src = Cursor::new(vec![0x12, 0x34, 0x56, 0x78]);

    let mut be_reader = NumberReader::with_order(ByteOrder::BE, src.clone());
    assert_eq!(0x12345678i32, be_reader.read_i32()?);

    let mut le_reader = NumberReader::with_order(ByteOrder::LE, src.clone());
    assert_eq!(0x78563412i32, le_reader.read_i32()?);

    Ok(())
}

pub fn read_u64(&mut self) -> Result<u64>

Reads an unsigned 64-bit integer from the underlying reader.

Errors

This method propagates any error recieved from the internal call to Read::read_exact.

Examples

use std::io::{self, Cursor};
use byte_order::{ByteOrder, NumberReader};

fn main() -> io::Result<()> {
    let src = Cursor::new(vec![0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56]);

    let mut be_reader = NumberReader::with_order(ByteOrder::BE, src.clone());
    assert_eq!(0x1234567890123456u64, be_reader.read_u64()?);

    let mut le_reader = NumberReader::with_order(ByteOrder::LE, src.clone());
    assert_eq!(0x5634129078563412u64, le_reader.read_u64()?);

    Ok(())
}

pub fn read_i64(&mut self) -> Result<i64>

Reads a signed 64-bit integer from the underlying reader.

Errors

This method propagates any error recieved from the internal call to Read::read_exact.

Examples

use std::io::{self, Cursor};
use byte_order::{ByteOrder, NumberReader};

fn main() -> io::Result<()> {
    let src = Cursor::new(vec![0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56]);

    let mut be_reader = NumberReader::with_order(ByteOrder::BE, src.clone());
    assert_eq!(0x1234567890123456i64, be_reader.read_i64()?);

    let mut le_reader = NumberReader::with_order(ByteOrder::LE, src.clone());
    assert_eq!(0x5634129078563412i64, le_reader.read_i64()?);

    Ok(())
}

pub fn read_u128(&mut self) -> Result<u128>

Reads an unsigned 128-bit integer from the underlying reader.

Errors

This method propagates any error recieved from the internal call to Read::read_exact.

Examples

use std::io::{self, Cursor};
use byte_order::{ByteOrder, NumberReader};

fn main() -> io::Result<()> {
    let src = Cursor::new(vec![
        0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56,
        0x78, 0x90, 0x12, 0x34, 0x56, 0x78, 0x90, 0x12,
    ]);

    let mut be_reader = NumberReader::with_order(ByteOrder::BE, src.clone());
    assert_eq!(0x12345678901234567890123456789012u128, be_reader.read_u128()?);

    let mut le_reader = NumberReader::with_order(ByteOrder::LE, src.clone());
    assert_eq!(0x12907856341290785634129078563412u128, le_reader.read_u128()?);

    Ok(())
}

pub fn read_i128(&mut self) -> Result<i128>

Reads a signed 128-bit integer from the underlying reader.

Errors

This method propagates any error recieved from the internal call to Read::read_exact.

Examples

use std::io::{self, Cursor};
use byte_order::{ByteOrder, NumberReader};

fn main() -> io::Result<()> {
    let src = Cursor::new(vec![
        0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56,
        0x78, 0x90, 0x12, 0x34, 0x56, 0x78, 0x90, 0x12,
    ]);

    let mut be_reader = NumberReader::with_order(ByteOrder::BE, src.clone());
    assert_eq!(0x12345678901234567890123456789012u128, be_reader.read_u128()?);

    let mut le_reader = NumberReader::with_order(ByteOrder::LE, src.clone());
    assert_eq!(0x12907856341290785634129078563412u128, le_reader.read_u128()?);

    Ok(())
}

pub fn read_f32(&mut self) -> Result<f32>

Reads a IEEE754 single-precision floating point number from the underlying reader.

Errors

This method propagates any error recieved from the internal call to Read::read_exact.

Examples

use std::io::{self, Cursor};
use byte_order::{ByteOrder, NumberReader};

fn main() -> io::Result<()> {
    let be_src = Cursor::new(vec![0x41, 0x48, 0x00, 0x00]);
    let mut be_reader = NumberReader::with_order(ByteOrder::BE, be_src);
    assert_eq!(12.5f32, be_reader.read_f32()?);

    let le_src = Cursor::new(vec![0x00, 0x00, 0x48, 0x41]);
    let mut le_reader = NumberReader::with_order(ByteOrder::LE, le_src);
    assert_eq!(12.5f32, le_reader.read_f32()?);

    Ok(())
}

pub fn read_f64(&mut self) -> Result<f64>

Reads a IEEE754 double-precision floating point number from the underlying reader.

Errors

This method propagates any error recieved from the internal call to Read::read_exact.

Examples

use std::io::{self, Cursor};
use byte_order::{ByteOrder, NumberReader};

fn main() -> io::Result<()> {
    let be_src = Cursor::new(vec![0x40, 0x29, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]);
    let mut be_reader = NumberReader::with_order(ByteOrder::BE, be_src);
    assert_eq!(12.5f64, be_reader.read_f64()?);

    let le_src = Cursor::new(vec![0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x29, 0x40]);
    let mut le_reader = NumberReader::with_order(ByteOrder::LE, le_src);
    assert_eq!(12.5f64, le_reader.read_f64()?);

    Ok(())
}

Trait Implementations

impl<R: Read> Read for NumberReader<R>

fn read(&mut self, buf: &mut [u8]) -> Result<usize>

Pull some bytes from this source into the specified buffer, returning how many bytes were read.

fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize, Error>

Like read, except that it reads into a slice of buffers.

fn is_read_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Reader has an efficient read_vectored implementation.

fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Error>

Reads all bytes until EOF in this source, placing them into buf.

fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>

Reads all bytes until EOF in this source, appending them to buf.

fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>

Reads the exact number of bytes required to fill buf.

fn read_buf(&mut self, buf: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Pull some bytes from this source into the specified buffer.

fn read_buf_exact(&mut self, cursor: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Reads the exact number of bytes required to fill cursor.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adaptor for this instance of Read.

fn bytes(self) -> Bytes<Self>

where Self: Sized,

Transforms this Read instance to an Iterator over its bytes.

fn chain<R>(self, next: R) -> Chain<Self, R>

where R: Read, Self: Sized,

Creates an adapter which will chain this stream with another.

fn take(self, limit: u64) -> Take<Self>

where Self: Sized,

Creates an adapter which will read at most limit bytes from it.