Initial commit for GitHub migration based on spice2x-25-03-03

src/spice2x/acio2emu/packet.h

@@ -0,0 +1,65 @@
+#pragma once
+
+#include <vector>
+#include <queue>
+#include <random> // std::linear_congruential_engine
+#include <cstdint>
+
+#include "acio2emu/internal/lz.h"
+
+namespace acio2emu {
+    struct Packet {
+        uint8_t node;
+        uint8_t tag;
+        std::vector<uint8_t> payload;
+    };
+
+    class PacketDecoder {
+    private:
+        Packet packet_ = {};
+
+        // order matters, don't change this enum!
+        enum payloadEncoding {
+            byteStuffing,
+            raw,
+            unknown,
+            replace,
+            lz,
+        } encoding_;
+
+        uint32_t payload_size_ = 0, payload_size_count_ = 0;
+
+        // payloadEncoding::replace state
+        uint8_t substitute_; 
+
+        // payloadEncoding::lz state
+        detail::InflateTransformer inflate_;
+
+        // deobfuscation state
+        bool obfuscated_;
+        std::linear_congruential_engine<uint32_t, 1103515245, 12345, 0> lcg_; 
+
+        enum class readStep {
+            idle,
+            readNode,
+            readTag,
+            readPayloadSize,
+            readPayloadFlags,
+            readReplacementByte,
+            readPayload,
+            readEscaped,
+        } step_ = readStep::idle;
+
+        void set_step_(readStep s);
+        void reset_(readStep s);
+
+        int update_payload_size_(uint8_t b);
+        uint8_t deobfuscate_(uint8_t b);
+
+    public:
+        bool update(uint8_t b);
+        const Packet &packet();
+    };
+
+    bool encode_packet(std::queue<uint8_t> &out, uint8_t node, uint8_t tag, const std::vector<uint8_t> &payload);
+}