Trait scroll::Cwrite

source ·
pub trait Cwrite<Ctx: Copy, I = usize>: Index<I> + IndexMut<RangeFrom<I>> {
    // Provided methods
    fn cwrite<N: IntoCtx<Ctx, <Self as Index<RangeFrom<I>>>::Output>>(
        &mut self,
        n: N,
        offset: I
    )
       where Ctx: Default { ... }
    fn cwrite_with<N: IntoCtx<Ctx, <Self as Index<RangeFrom<I>>>::Output>>(
        &mut self,
        n: N,
        offset: I,
        ctx: Ctx
    ) { ... }
}
Expand description

Core-write - core, no_std friendly trait for writing basic types into byte buffers. Cannot fail unless the buffer is too small, in which case an assert fires and the program panics. Similar to Cread, if your type implements IntoCtx then you can cwrite(your_type, offset).

Example

use scroll::{ctx, Cwrite};

#[repr(packed)]
struct Bar {
    foo: i32,
    bar: u32,
}

impl ctx::IntoCtx<scroll::Endian> for Bar {
    fn into_ctx(self, bytes: &mut [u8], ctx: scroll::Endian) {
        use scroll::Cwrite;
        bytes.cwrite_with(self.foo, 0, ctx);
        bytes.cwrite_with(self.bar, 4, ctx);
    }
}

let bar = Bar { foo: -1, bar: 0xdeadbeef };
let mut bytes = [0x0; 16];
bytes.cwrite::<Bar>(bar, 0);

Provided Methods§

source

fn cwrite<N: IntoCtx<Ctx, <Self as Index<RangeFrom<I>>>::Output>>( &mut self, n: N, offset: I )
where Ctx: Default,

Writes n into Self at offset; uses default context. For the primitive types, this will be the target machine’s endianness.

Example
use scroll::{Cwrite, Cread};
let mut bytes = [0x0; 16];
bytes.cwrite::<i64>(42, 0);
bytes.cwrite::<u32>(0xdeadbeef, 8);

assert_eq!(bytes.cread::<i64>(0), 42);
assert_eq!(bytes.cread::<u32>(8), 0xdeadbeef);
source

fn cwrite_with<N: IntoCtx<Ctx, <Self as Index<RangeFrom<I>>>::Output>>( &mut self, n: N, offset: I, ctx: Ctx )

Writes n into Self at offset with ctx

Example
use scroll::{Cwrite, Cread, LE, BE};
let mut bytes = [0x0; 0x10];
bytes.cwrite_with::<i64>(42, 0, LE);
bytes.cwrite_with::<u32>(0xdeadbeef, 8, BE);
assert_eq!(bytes.cread_with::<i64>(0, LE), 42);
assert_eq!(bytes.cread_with::<u32>(8, LE), 0xefbeadde);

Object Safety§

This trait is not object safe.

Implementors§

source§

impl<Ctx: Copy, I, W: ?Sized + Index<I> + IndexMut<RangeFrom<I>>> Cwrite<Ctx, I> for W