Add message IDs, transport interface, client package, extract protocol headers

include/device.h

@@ -0,0 +1,51 @@
+#pragma once
+#include <cstdint>
+#include <vector>
+#include "msgpackpp.h"
+#include "halfsiphash.h"
+#include "static_vector.h"
+#include "protocol.h"
+
+static constexpr uint8_t hash_key[8] = {};
+
+struct DecodedMessage {
+    uint32_t message_id;
+    int8_t type_id;
+};
+
+inline std::vector<uint8_t> pack_envelope(uint32_t message_id, const std::vector<uint8_t> &payload) {
+    uint32_t checksum = halfsiphash::hash32(payload.data(), payload.size(), hash_key);
+    msgpackpp::packer p;
+    p.pack(Envelope{message_id, checksum, payload});
+    return p.get_payload();
+}
+
+template <typename T>
+inline std::vector<uint8_t> encode_response(uint32_t message_id, const T &msg) {
+    msgpackpp::packer inner;
+    inner.pack(msg);
+    return pack_envelope(message_id, inner.get_payload());
+}
+
+inline msgpackpp::result<DecodedMessage> try_decode(const uint8_t *data, size_t len) {
+    msgpackpp::parser p(data, static_cast<int>(len));
+
+    Envelope env;
+    auto r = msgpackpp::unpack(p, env);
+    if (!r) return std::unexpected(r.error());
+
+    uint32_t expected = halfsiphash::hash32(env.payload.data(), env.payload.size(), hash_key);
+    if (env.checksum != expected) return std::unexpected(msgpackpp::error_code::invalid);
+
+    msgpackpp::parser inner(env.payload.data(), static_cast<int>(env.payload.size()));
+    if (!inner.is_ext()) return std::unexpected(msgpackpp::error_code::type_error);
+    auto ext = inner.get_ext();
+    if (!ext) return std::unexpected(ext.error());
+
+    return DecodedMessage{env.message_id, std::get<0>(*ext)};
+}
+
+template <size_t N>
+inline msgpackpp::result<DecodedMessage> try_decode(const static_vector<uint8_t, N> &buf) {
+    return try_decode(buf.data(), buf.size());
+}