Unify Send/Read error enums

src/avclan/avclan.h

@@ -0,0 +1,57 @@
+// Copyright (C) 2026 Allen Hill <allenofthehills@gmail.com>
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#pragma once
+
+#ifdef __cplusplus
+  #include <cstdint>
+  #define AVCLAN_ENUM_CLASS enum class
+#else
+  #include <stdint.h>
+  #define AVCLAN_ENUM_CLASS enum
+#endif
+
+#ifdef __cplusplus
+namespace avclan::detail {
+struct Error {
+#endif
+
+  // Error enums are ordered such that a lower numeric value corresponds to
+  // more progress/success before an error occured, with 0 being no errors
+  AVCLAN_ENUM_CLASS Read : uint8_t {
+  BAD_DATA_PARITY = 0x01,
+  BAD_LENGTH_RANGE,
+  BAD_LENGTH_PARITY,
+  BAD_PERIPHERAL_PARITY,
+  BAD_CONTROLLER_PARITY,
+  BAD_CONTROL_PARITY,
+  BAD_PARITY, // non-specific bad parity
+  STARTBIT_TOO_SHORT,
+  STARTBIT_TOO_LONG,
+  BAD_STARTBIT,
+}
+// #ifndef __cplusplus
+// Read
+// #endif
+;
+
+  AVCLAN_ENUM_CLASS Send : uint8_t {
+  NAK_DATA = 0x01,
+  NAK_MESSAGE_LENGTH,
+  NAK_CONTROL,
+  NAK_ADDRESS,
+  NAK, // non-specific NAK
+  BUSY,
+  MUTED,
+}
+// #ifndef __cplusplus
+// Send
+// #endif
+;
+
+#ifdef __cplusplus
+};
+} // namespace avclan::detail
+#endif
+
+#undef AVCLAN_ENUM_CLASS