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pub use holochain_wasmer_common::allocation;
pub use holochain_wasmer_common::bytes;
pub use holochain_wasmer_common::error::Error;
pub use holochain_wasmer_common::*;

extern "C" {
    // memory stuff
    fn __import_allocation(guest_allocation_ptr: AllocationPtr, host_allocation_ptr: AllocationPtr);
    fn __import_bytes(host_allocation_ptr: AllocationPtr, guest_bytes_ptr: Ptr);
}

/// given a pointer to an allocation on the host, copy the allocation into the guest and return the
/// guest's pointer to it
pub fn map_bytes(host_allocation_ptr: Ptr) -> AllocationPtr {
    let tmp_allocation_ptr = allocation::allocate(allocation::ALLOCATION_BYTES_ITEMS as Len);
    unsafe {
        __import_allocation(tmp_allocation_ptr, host_allocation_ptr);
    };
    // this allocation has the correct length but host bytes ptr
    let [_, len] = allocation::from_allocation_ptr(tmp_allocation_ptr);
    allocation::deallocate(tmp_allocation_ptr, len);
    let guest_bytes_ptr = allocation::allocate(len);
    unsafe {
        __import_bytes(host_allocation_ptr, guest_bytes_ptr);
    };
    allocation::to_allocation_ptr([guest_bytes_ptr, len])
}

#[macro_export]
macro_rules! host_call {
    ($func_name:ident, $input:ident) => {
        host_string_from_host_allocation_ptr(unsafe {
            $func_name(allocation::to_allocation_ptr([
                $input.as_ptr() as Ptr,
                $input.len() as Len,
            ]))
        })
    };
}