x/src/cffi.rs

/// appends zeroes to the end of the string and converts it into a pointer
/// useful for quick ffi
#[macro_export]
macro_rules! cstr {
    ($str:expr) => {
        concat!($str,"\0\0").as_ptr() as *const i8
    }
}


/// utility macro for inline c functions
///
/// |  macro  |  rust  |
/// |-----------|----------|
/// | ```cfn!( () -> usize )``` | ``` extern "C" fn() -> usize``` |
/// | ```cfn!( (usize) -> usize )``` | ``` extern "C" fn(usize) -> usize``` |
/// | ```cfn!( (usize) )``` | ``` extern "C" fn(usize)``` |
/// | ```cfn!( (u32, usize, usize) -> u32 )``` | ``` extern "C" fn(u32, usize, usize) -> u32``` |
#[macro_export]
macro_rules! cfn {
    ( ($($t:ty),*)) => {
        extern "C" fn($( $t ),* )
    };
    ( ($($t:ty),*) -> $r:ty) => {
        extern "C" fn($( $t ),* ) -> $r
    }
}

/// utility macro for pointer chains
#[macro_export]
macro_rules! ptr_chain {
    ($x: expr, $y:expr) => {{
        (*core::mem::transmute::<_,*const usize>(core::mem::transmute::<_,usize>($x) + $y))
    }};

    ($x: expr, $y:expr, $( $z:expr ),+ ) => {{
        $crate::ptr_chain!( $crate::ptr_chain!($x, $y), $( $z ),+ )
    }};
}