arrays: move carray_to_varray from builtin, make it generic (#15503)

Author: larpon

vlib/arrays/arrays.v

@@ -570,3 +570,12 @@ fn can_copy_bits<T>() bool {
 	}
 	return false
 }
+
+// carray_to_varray copies a C byte array into a V array of type `T`.
+// See also: `cstring_to_vstring`
+[unsafe]
+pub fn carray_to_varray<T>(c_array voidptr, c_array_len int) []T {
+	mut v_array := []T{len: c_array_len}
+	unsafe { vmemcpy(v_array.data, c_array, c_array_len * int(sizeof(T))) }
+	return v_array
+}

vlib/builtin/array.v

@@ -126,15 +126,6 @@ fn new_array_from_c_array_no_alloc(len int, cap int, elm_size int, c_array voidp
 	return arr
 }
 
-// carray_to_varray copies a C byte array into a V `u8` array.
-// See also: `cstring_to_vstring`
-[unsafe]
-pub fn carray_to_varray(c_array voidptr, c_array_len int) []u8 {
-	mut v_array := []u8{len: c_array_len}
-	unsafe { vmemcpy(v_array.data, c_array, c_array_len * int(sizeof(u8))) }
-	return v_array
-}
-
 // Private function. Increases the `cap` of an array to the
 // required value by copying the data to a new memory location
 // (creating a clone) unless `a.cap` is already large enough.

vlib/v/tests/c_array_test.c

@@ -6,3 +6,10 @@ void* gen_c_array(int size) {
     return c_array;
 }
 
+void* gen_c_int_array(int size) {
+    int *c_array = malloc(size);
+    for(int i = 0; i < size; i++) {
+        c_array[i] = i & 0xFF;
+    }
+    return c_array;
+}

vlib/v/tests/c_array_test.v

@@ -1,14 +1,26 @@
+import arrays
+
 #insert "@VEXEROOT/vlib/v/tests/c_array_test.c"
 
 fn C.gen_c_array(size int) voidptr
 
+fn C.gen_c_int_array(size int) voidptr
+
 fn test_carray_to_varray() {
 	size := 10
 	mut c_array := C.gen_c_array(size)
-	v_array := unsafe { carray_to_varray(c_array, size) }
+	v_u8_array := unsafe { arrays.carray_to_varray<u8>(c_array, size) }
 	unsafe { C.free(c_array) }
-	assert v_array.len == size
-	for i, elem in v_array {
+	assert v_u8_array.len == size
+	for i, elem in v_u8_array {
+		assert elem == i
+	}
+
+	c_int_array := C.gen_c_int_array(size)
+	v_int_array := unsafe { arrays.carray_to_varray<int>(c_int_array, size) }
+	unsafe { C.free(c_int_array) }
+	assert v_int_array.len == size
+	for i, elem in v_int_array {
 		assert elem == i
 	}
 }