Function subslice_range

crates/wasmtime/src/runtime/code_memory.rs:702–712

Returns the range of `inner` within `outer`, such that `outer[range]` is the same as `inner`. This method requires that `inner` is a sub-slice of `outer`, and if that isn't true then this method will panic.

(inner: &[u8], outer: &[u8])

/// This method requires that `inner` is a sub-slice of `outer`, and if that
/// isn't true then this method will panic.
fn subslice_range(inner: &[u8], outer: &[u8]) -> Range<usize> {
    if inner.len() == 0 {
        return 0..0;
    }

    assert!(outer.as_ptr() <= inner.as_ptr());
    assert!((&inner[inner.len() - 1] as *const _) <= (&outer[outer.len() - 1] as *const _));

    let start = inner.as_ptr() as usize - outer.as_ptr() as usize;
    start..start + inner.len()
}