Change convert_space_ffi to be generic

Includes the usual 4 monotyped functions but without a macro because
it's only used once.

Author: Beinsezii

scripts/test_ctypes.py

@@ -14,13 +14,13 @@
 
 colcon = ctypes.CDLL(f"./target/release/{LIBRARY}")
 
-colcon.convert_space_ffi.argtypes = [
+colcon.convert_space_ffi_3f32.argtypes = [
     ctypes.c_char_p,
     ctypes.c_char_p,
     cpixels,
     ctypes.c_uint,
 ]
-colcon.convert_space_ffi.restype = ctypes.c_int32
+colcon.convert_space_ffi_3f32.restype = ctypes.c_int32
 
 # up
 colcon.srgb_to_hsv_3f32.argtypes = [cpixel]
@@ -141,6 +141,6 @@ def pixcmp(a, b):
 pixcmp(list(pix), HSV)
 
 pix = (ctypes.c_float * len(SRGB))(*SRGB)
-if colcon.convert_space_ffi("srgb".encode(), "lch".encode(), pix, len(pix)) != 0:
+if colcon.convert_space_ffi_3f32("srgb".encode(), "lch".encode(), pix, len(pix)) != 0:
     print("CONVERT SPACE FAIL")
 pixcmp(list(pix), LCH)

src/lib.rs

@@ -744,8 +744,17 @@ where
 /// Same as `convert_space_sliced` but with FFI types.
 ///
 /// Returns 0 on success, 1 on invalid `from`, 2 on invalid `to`, 3 on invalid `pixels`
-#[no_mangle]
-pub extern "C" fn convert_space_ffi(from: *const c_char, to: *const c_char, pixels: *mut f32, len: usize) -> i32 {
+///
+/// `len` is in elements rather than bytes
+pub fn convert_space_ffi<T: DType, const N: usize>(
+    from: *const c_char,
+    to: *const c_char,
+    pixels: *mut T,
+    len: usize,
+) -> i32
+where
+    Channels<N>: ValidChannels,
+{
     let from = unsafe {
         if from.is_null() {
             return 1;
@@ -785,7 +794,7 @@ pub extern "C" fn convert_space_ffi(from: *const c_char, to: *const c_char, pixe
             core::slice::from_raw_parts_mut(pixels, len)
         }
     };
-    convert_space_sliced::<_, 3>(from, to, pixels);
+    convert_space_sliced::<T, N>(from, to, pixels);
     0
 }
 
@@ -1306,6 +1315,23 @@ where
 
 // ### MONOTYPED EXTERNAL FUNCTIONS ### {{{
 
+#[no_mangle]
+extern "C" fn convert_space_ffi_3f32(from: *const c_char, to: *const c_char, pixels: *mut f32, len: usize) -> i32 {
+    convert_space_ffi::<_, 3>(from, to, pixels, len)
+}
+#[no_mangle]
+extern "C" fn convert_space_ffi_4f32(from: *const c_char, to: *const c_char, pixels: *mut f32, len: usize) -> i32 {
+    convert_space_ffi::<_, 4>(from, to, pixels, len)
+}
+#[no_mangle]
+extern "C" fn convert_space_ffi_3f64(from: *const c_char, to: *const c_char, pixels: *mut f64, len: usize) -> i32 {
+    convert_space_ffi::<_, 3>(from, to, pixels, len)
+}
+#[no_mangle]
+extern "C" fn convert_space_ffi_4f64(from: *const c_char, to: *const c_char, pixels: *mut f64, len: usize) -> i32 {
+    convert_space_ffi::<_, 4>(from, to, pixels, len)
+}
+
 macro_rules! cdef1 {
     ($base:ident, $f32:ident, $f64:ident) => {
         #[no_mangle]