SymField rewrite (#1444)

* First WIP symfield

* Cleanup widget code

* Rebase and format

* Fix 'to_integer' bug, fix siggen UI.

* to_string_hex fix, unit tests for string code

* Pass instance in callback

* Fix on_change callbacks

* Fix keyfob (not active)

* to_byte_array, coaster tx cleanup

* Add to_byte_array tests

* Changes in ui_numbers

* Fix ui_encoders

* Format

* Fix modemsetup view's symfields

* Remove header

* Format

firmware/common/utility.hpp

@@ -22,12 +22,13 @@
 #ifndef __UTILITY_H__
 #define __UTILITY_H__
 
-#include <type_traits>
+#include <algorithm>
+#include <array>
+#include <complex>
 #include <cstdint>
 #include <cstddef>
-#include <algorithm>
-#include <complex>
 #include <memory>
+#include <type_traits>
 
 #define LOCATE_IN_RAM __attribute__((section(".ramtext")))
 
@@ -141,6 +142,16 @@ constexpr std::enable_if_t<is_flags_type_v<TEnum>, bool> flags_enabled(TEnum val
     return (i_value & i_flags) == i_flags;
 }
 
+// TODO: Constrain to integrals?
+/* Converts an integer into a byte array. */
+template <typename T, size_t N = sizeof(T)>
+constexpr std::array<uint8_t, N> to_byte_array(T value) {
+    std::array<uint8_t, N> bytes{};
+    for (size_t i = 0; i < N; ++i)
+        bytes[i] = (value >> ((N - i - 1) * 8)) & 0xFF;
+    return bytes;
+}
+
 /* Returns value constrained to min and max. */
 template <class T>
 constexpr const T& clip(const T& value, const T& minimum, const T& maximum) {