hopper-core 0.1.0

Core engine for the Hopper zero-copy state framework. Account memory architecture, ABI types, validation graphs, phased execution, zero-copy collections, layout evolution, and cross-program interfaces.
Documentation 
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//! Zero-copy overlay utilities.

use super::pod::{FixedLayout, Pod};
use hopper_runtime::error::ProgramError;

/// Overlay immutable reference to a Pod type at the start of a byte slice.
#[inline(always)]
pub fn overlay<T: Pod + FixedLayout>(data: &[u8]) -> Result<&T, ProgramError> {
    super::pod::pod_from_bytes(data)
}

/// Overlay mutable reference to a Pod type at the start of a byte slice.
#[inline(always)]
pub fn overlay_mut<T: Pod + FixedLayout>(data: &mut [u8]) -> Result<&mut T, ProgramError> {
    super::pod::pod_from_bytes_mut(data)
}

/// Overlay at a specific offset (immutable).
#[inline(always)]
#[allow(dead_code)]
pub fn overlay_at<T: Pod + FixedLayout>(data: &[u8], offset: usize) -> Result<&T, ProgramError> {
    if offset > data.len() {
        return Err(ProgramError::InvalidAccountData);
    }
    super::pod::pod_from_bytes(&data[offset..])
}

/// Overlay at a specific offset (mutable).
#[inline(always)]
#[allow(dead_code)]
pub fn overlay_at_mut<T: Pod + FixedLayout>(
    data: &mut [u8],
    offset: usize,
) -> Result<&mut T, ProgramError> {
    if offset > data.len() {
        return Err(ProgramError::InvalidAccountData);
    }
    super::pod::pod_from_bytes_mut(&mut data[offset..])
}