Trait scroll::IOwrite

pub trait IOwrite<Ctx: Copy>: Write {
    fn iowrite<N: SizeWith<Ctx> + IntoCtx<Ctx>>(&mut self, n: N) -> Result<()>
    where
        Ctx: Default,
    { ... }
    fn iowrite_with<N: SizeWith<Ctx> + IntoCtx<Ctx>>(
        &mut self, 
        n: N, 
        ctx: Ctx
    ) -> Result<()> { ... }
}

An extension trait to std::io::Write streams; this only serializes simple types, like u8, i32, f32, usize, etc.

To write custom types with a single iowrite::<YourType> call, implement IntoCtx and SizeWith for YourType.

Provided methods

fn iowrite<N: SizeWith<Ctx> + IntoCtx<Ctx>>(&mut self, n: N) -> Result<()> where
    Ctx: Default, 

Writes the type N into Self, with the parsing context ctx. NB: this will panic if the type you’re writing has a size greater than 256. Plans are to have this allocate in larger cases.

For the primitive numeric types, this will be at the host machine’s endianness.

Example

use scroll::IOwrite;
use std::io::Cursor;

let mut bytes = [0x0u8; 4];
let mut bytes = Cursor::new(&mut bytes[..]);
bytes.iowrite(0xdeadbeef as u32).unwrap();

#[cfg(target_endian = "little")]
assert_eq!(bytes.into_inner(), [0xef, 0xbe, 0xad, 0xde,]);
#[cfg(target_endian = "big")]
assert_eq!(bytes.into_inner(), [0xde, 0xad, 0xbe, 0xef,]);

fn iowrite_with<N: SizeWith<Ctx> + IntoCtx<Ctx>>(
    &mut self,
    n: N,
    ctx: Ctx
) -> Result<()>

Writes the type N into Self, with the parsing context ctx. NB: this will panic if the type you’re writing has a size greater than 256. Plans are to have this allocate in larger cases.

For the primitive numeric types, this will be at the host machine’s endianness.

Example

use scroll::{IOwrite, LE, BE};
use std::io::{Write, Cursor};

let mut bytes = [0x0u8; 10];
let mut cursor = Cursor::new(&mut bytes[..]);
cursor.write_all(b"hello").unwrap();
cursor.iowrite_with(0xdeadbeef as u32, BE).unwrap();
assert_eq!(cursor.into_inner(), [0x68, 0x65, 0x6c, 0x6c, 0x6f, 0xde, 0xad, 0xbe, 0xef, 0x0]);

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Implementors

impl<Ctx: Copy, W: Write + ?Sized> IOwrite<Ctx> for W

Types that implement Write get methods defined in IOwrite for free.

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