functions for manipulating packets

Cargo.lock

@@ -408,7 +408,7 @@ dependencies = [
 [[package]]
 name = "servicepoint"
 version = "0.13.2"
-source = "git+https://git.berlin.ccc.de/servicepoint/servicepoint/?branch=next#aafa2bc9f91c3ae7d88607bf545d9665d50fc0db"
+source = "git+https://git.berlin.ccc.de/servicepoint/servicepoint/?branch=next#971bee5065139f220022e8108cfaa9c263b8a8a0"
 dependencies = [
  "bitvec",
  "bzip2",

example/main.c

@@ -16,7 +16,12 @@ int main(void) {
     if (command == NULL)
       return 1;
 
-    sp_connection_send_command(connection, command);
+    Packet *packet = sp_packet_from_command(command);
+
+    Header *header = sp_packet_get_header(packet);
+    printf("[%d, %d, %d, %d, %d]\n", header->command_code, header->a, header->b, header->c, header->d);
+
+    sp_connection_send_packet(connection, packet);
 
     sp_connection_free(connection);
     return 0;

include/servicepoint.h

@@ -1908,7 +1908,11 @@ Packet *sp_packet_from_parts(Header header,
                              const uint8_t *payload,
                              size_t payload_len);
 
-Header sp_packet_get_header(const Packet *packet);
+Header *sp_packet_get_header(Packet *packet);
+
+SPByteSlice sp_packet_get_payload(Packet *packet);
+
+void sp_packet_set_payload(Packet *packet, SPByteSlice data);
 
 /**
  * Tries to load a [SPPacket] from the passed array with the specified length.
@@ -1931,6 +1935,8 @@ Header sp_packet_get_header(const Packet *packet);
 Packet *sp_packet_try_load(const uint8_t *data,
                            size_t length);
 
+void sp_packet_write_to(const Packet *packet, SPByteSlice buffer);
+
 #ifdef __cplusplus
 }  // extern "C"
 #endif  // __cplusplus

src/bitmap.rs

@@ -18,7 +18,6 @@ use std::ptr::NonNull;
 
 use crate::byte_slice::SPByteSlice;
 
-
 /// Creates a new [SPBitmap] with the specified dimensions.
 ///
 /// # Arguments
@@ -63,7 +62,8 @@ pub unsafe extern "C" fn sp_bitmap_new(
 /// - the returned instance is freed in some way, either by using a consuming function or
 ///   by explicitly calling [sp_bitmap_free].
 #[no_mangle]
-pub unsafe extern "C" fn sp_bitmap_new_screen_sized() -> NonNull<servicepoint::Bitmap> {
+pub unsafe extern "C" fn sp_bitmap_new_screen_sized(
+) -> NonNull<servicepoint::Bitmap> {
     let result = Box::new(servicepoint::Bitmap::max_sized());
     NonNull::from(Box::leak(result))
 }
@@ -235,7 +235,10 @@ pub unsafe extern "C" fn sp_bitmap_set(
 /// - `bitmap` points to a valid [SPBitmap]
 /// - `bitmap` is not written to or read from concurrently
 #[no_mangle]
-pub unsafe extern "C" fn sp_bitmap_fill(bitmap: *mut servicepoint::Bitmap, value: bool) {
+pub unsafe extern "C" fn sp_bitmap_fill(
+    bitmap: *mut servicepoint::Bitmap,
+    value: bool,
+) {
     assert!(!bitmap.is_null());
     unsafe { (*bitmap).fill(value) };
 }
@@ -256,7 +259,9 @@ pub unsafe extern "C" fn sp_bitmap_fill(bitmap: *mut servicepoint::Bitmap, value
 ///
 /// - `bitmap` points to a valid [SPBitmap]
 #[no_mangle]
-pub unsafe extern "C" fn sp_bitmap_width(bitmap: *const servicepoint::Bitmap) -> usize {
+pub unsafe extern "C" fn sp_bitmap_width(
+    bitmap: *const servicepoint::Bitmap,
+) -> usize {
     assert!(!bitmap.is_null());
     unsafe { (*bitmap).width() }
 }
@@ -277,7 +282,9 @@ pub unsafe extern "C" fn sp_bitmap_width(bitmap: *const servicepoint::Bitmap) ->
 ///
 /// - `bitmap` points to a valid [SPBitmap]
 #[no_mangle]
-pub unsafe extern "C" fn sp_bitmap_height(bitmap: *const servicepoint::Bitmap) -> usize {
+pub unsafe extern "C" fn sp_bitmap_height(
+    bitmap: *const servicepoint::Bitmap,
+) -> usize {
     assert!(!bitmap.is_null());
     unsafe { (*bitmap).height() }
 }
@@ -300,9 +307,5 @@ pub unsafe extern "C" fn sp_bitmap_unsafe_data_ref(
     bitmap: *mut servicepoint::Bitmap,
 ) -> SPByteSlice {
     assert!(!bitmap.is_null());
-    let data = unsafe { (*bitmap).data_ref_mut() };
-    SPByteSlice {
-        start: NonNull::new(data.as_mut_ptr_range().start).unwrap(),
-        length: data.len(),
-    }
+    unsafe { SPByteSlice::from_slice((*bitmap).data_ref_mut()) }
 }

src/bitvec.rs

@@ -275,9 +275,5 @@ pub unsafe extern "C" fn sp_bitvec_unsafe_data_ref(
     bit_vec: *mut SPBitVec,
 ) -> SPByteSlice {
     assert!(!bit_vec.is_null());
-    let data = unsafe { (*bit_vec).0.as_raw_mut_slice() };
-    SPByteSlice {
-        start: NonNull::new(data.as_mut_ptr_range().start).unwrap(),
-        length: data.len(),
-    }
+    unsafe { SPByteSlice::from_slice((*bit_vec).0.as_raw_mut_slice() ) }
 }

src/brightness_grid.rs

@@ -318,9 +318,6 @@ pub unsafe extern "C" fn sp_brightness_grid_unsafe_data_ref(
     assert_eq!(core::mem::size_of::<servicepoint::Brightness>(), 1);
     let data = unsafe { (*brightness_grid).data_ref_mut() };
     // this assumes more about the memory layout than rust guarantees. yikes!
-    let data: &mut [u8] = unsafe { transmute(data) };
-    SPByteSlice {
-        start: NonNull::new(data.as_mut_ptr_range().start).unwrap(),
-        length: data.len(),
-    }
+    unsafe { SPByteSlice::from_slice(transmute(data)) }
+
 }

src/byte_slice.rs

@@ -22,3 +22,22 @@ pub struct SPByteSlice {
     /// The amount of memory in bytes
     pub length: usize,
 }
+
+impl SPByteSlice {
+    pub(crate) unsafe fn as_slice(&self) -> &[u8] {
+        unsafe { std::slice::from_raw_parts(self.start.as_ptr(), self.length) }
+    }
+
+    pub(crate) unsafe fn as_slice_mut(&mut self) -> &mut [u8] {
+        unsafe {
+            std::slice::from_raw_parts_mut(self.start.as_ptr(), self.length)
+        }
+    }
+
+    pub(crate) unsafe fn from_slice(slice: &mut [u8]) -> Self {
+        Self {
+            start: NonNull::new(slice.as_mut_ptr()).unwrap(),
+            length: slice.len(),
+        }
+    }
+}

src/cp437_grid.rs

@@ -280,9 +280,5 @@ pub unsafe extern "C" fn sp_cp437_grid_height(
 pub unsafe extern "C" fn sp_cp437_grid_unsafe_data_ref(
     cp437_grid: *mut SPCp437Grid,
 ) -> SPByteSlice {
-    let data = unsafe { (*cp437_grid).0.data_ref_mut() };
-    SPByteSlice {
-        start: NonNull::new(data.as_mut_ptr_range().start).unwrap(),
-        length: data.len(),
-    }
+    unsafe {SPByteSlice::from_slice((*cp437_grid).0.data_ref_mut()) }
 }

src/packet.rs

@@ -5,8 +5,9 @@
 //!
 //! The raw packet
 
-use std::ptr::NonNull;
+use crate::SPByteSlice;
 use servicepoint::{Header, Packet, TypedCommand};
+use std::ptr::NonNull;
 
 /// Turns a [SPCommand] into a [SPPacket].
 /// The [SPCommand] gets consumed.
@@ -107,19 +108,40 @@ pub unsafe extern "C" fn sp_packet_from_parts(
         Vec::from(payload)
     };
 
-    let packet = Box::new(Packet {
-        header,
-        payload,
-    });
+    let packet = Box::new(Packet { header, payload });
     NonNull::from(Box::leak(packet))
 }
 
 #[no_mangle]
-pub unsafe extern "C" fn sp_packet_get_header(
-    packet: *const Packet,
-) -> Header {
+pub unsafe extern "C" fn sp_packet_get_header(packet: *mut Packet) -> *mut Header {
     assert!(!packet.is_null());
-    unsafe { (*packet).header }
+    &mut unsafe { (*packet).header }
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn sp_packet_get_payload(packet: *mut Packet) -> SPByteSlice {
+    assert!(!packet.is_null());
+    unsafe { SPByteSlice::from_slice(&mut *(*packet).payload) }
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn sp_packet_set_payload(packet: *mut Packet, data: SPByteSlice) {
+    assert!(!packet.is_null());
+    unsafe {
+        (*packet).payload = data.as_slice().to_vec()
+    }
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn sp_packet_write_to(
+    packet: *const Packet,
+    mut buffer: SPByteSlice,
+) {
+    assert!(!packet.is_null());
+
+    unsafe {
+        (*packet).serialize_to(buffer.as_slice_mut());
+    }
 }
 
 /// Clones a [SPPacket].