servicepoint-binding-c/src/packet.rs

127 lines
3.3 KiB
Rust

use crate::{
containers::ByteSlice,
mem::{heap_clone, heap_drop, heap_move_nonnull, heap_move_ok},
};
use servicepoint::{CommandCode, Header, Packet};
use std::ptr::NonNull;
/// Tries to load a [Packet] from the passed array with the specified length.
///
/// returns: NULL in case of an error, pointer to the allocated packet otherwise
#[no_mangle]
pub unsafe extern "C" fn sp_packet_try_load(data: ByteSlice) -> *mut Packet {
let data = unsafe { data.as_slice() };
heap_move_ok(servicepoint::Packet::try_from(data))
}
/// Creates a raw [Packet] from parts.
///
/// returns: new instance. Will never return null.
#[no_mangle]
pub unsafe extern "C" fn sp_packet_from_parts(
header: Header,
payload: ByteSlice,
) -> NonNull<Packet> {
let payload = if payload == ByteSlice::INVALID {
None
} else {
Some(Vec::from(unsafe { payload.as_slice() }))
};
heap_move_nonnull(Packet { header, payload })
}
/// Returns a pointer to the header field of the provided packet.
///
/// The returned header can be changed and will be valid for the lifetime of the packet.
#[no_mangle]
pub unsafe extern "C" fn sp_packet_get_header(
packet: NonNull<Packet>,
) -> NonNull<Header> {
NonNull::from(unsafe { &mut (*packet.as_ptr()).header })
}
/// Returns a pointer to the current payload of the provided packet.
///
/// Returns an [ByteSlice::INVALID] instance in case the packet does not have any payload.
///
/// The returned memory can be changed and will be valid until a new payload is set.
#[no_mangle]
pub unsafe extern "C" fn sp_packet_get_payload(
packet: NonNull<Packet>,
) -> ByteSlice {
unsafe {
match &mut (*packet.as_ptr()).payload {
None => ByteSlice::INVALID,
Some(payload) => ByteSlice::from_slice(payload),
}
}
}
/// Sets the payload of the provided packet to the provided data.
///
/// This makes previous payload pointers invalid.
#[no_mangle]
pub unsafe extern "C" fn sp_packet_set_payload(
packet: NonNull<Packet>,
data: ByteSlice,
) {
unsafe {
(*packet.as_ptr()).payload = if data == ByteSlice::INVALID {
None
} else {
Some(data.as_slice().to_vec())
}
}
}
/// Serialize the packet into the provided buffer.
///
/// # Panics
///
/// - if the buffer is not big enough to hold header+payload.
#[no_mangle]
pub unsafe extern "C" fn sp_packet_serialize_to(
packet: NonNull<Packet>,
mut buffer: ByteSlice,
) {
unsafe {
packet.as_ref().serialize_to(buffer.as_slice_mut());
}
}
/// Clones a [Packet].
///
/// returns: a new [Packet] instance.
#[no_mangle]
pub unsafe extern "C" fn sp_packet_clone(
packet: NonNull<Packet>,
) -> NonNull<Packet> {
unsafe { heap_clone(packet) }
}
/// Deallocates a [Packet].
#[no_mangle]
pub unsafe extern "C" fn sp_packet_free(packet: NonNull<Packet>) {
unsafe { heap_drop(packet) }
}
/// Converts u16 into [CommandCode].
///
/// If the provided value is not valid, false is returned and result is not changed.
#[no_mangle]
pub unsafe extern "C" fn sp_u16_to_command_code(
code: u16,
result: *mut CommandCode,
) -> bool {
match CommandCode::try_from(code) {
Ok(code) => {
unsafe {
*result = code;
}
true
}
Err(_) => false,
}
}