From a5b377745116de2b269cdfc5b90f08f46d0432d2 Mon Sep 17 00:00:00 2001
From: hovertank3d <isk@lzcnt.space>
Date: Thu, 13 Nov 2025 23:02:56 +0100
Subject: initial commit

---
 include/net/packet.hpp | 98 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 98 insertions(+)
 create mode 100644 include/net/packet.hpp

(limited to 'include/net/packet.hpp')

diff --git a/include/net/packet.hpp b/include/net/packet.hpp
new file mode 100644
index 0000000..f2094c0
--- /dev/null
+++ b/include/net/packet.hpp
@@ -0,0 +1,98 @@
+#pragma once
+
+#include <array>
+#include <cassert>
+#include <cstddef>
+#include <cstdint>
+#include <cstdio>
+#include <cstring>
+#include <format>
+#include <stdexcept>
+#include <vector>
+
+#include <sys/socket.h>
+#include <sys/types.h>
+
+#include <boost/pfr/core.hpp>
+#include <zlib.h>
+
+#include "types.hpp"
+
+namespace net {
+
+namespace packet {
+
+using packet_header = std::tuple<uint8_t, uint16_t>;
+
+template <packet T>
+void decode_packet(std::span<uint8_t> payload, T& t)
+{
+	std::size_t offset = 0;
+
+	boost::pfr::for_each_field(t, [&payload, &offset](auto& field, int i) {
+		if (offset >= payload.size()) {
+			throw std::runtime_error("Received invalid packet");
+		}
+		offset += decode_field(payload.subspan(offset), field);
+	});
+
+	if (offset < payload.size()) {
+		throw std::runtime_error(std::format("{}: {}", offset, payload.size()));
+	}
+}
+
+template <packet T>
+std::vector<uint8_t> encode_raw_packet(T& t)
+{
+	std::vector<uint8_t> payload;
+
+	boost::pfr::for_each_field(t, [&payload](auto& field) {
+		encode_field(payload, field);
+	});
+
+	return payload;
+}
+
+template <packet T>
+std::vector<uint8_t> encode_packet(T& t)
+{
+	return encode_raw_packet(t);
+}
+
+template <compressed_packet T>
+std::vector<uint8_t> encode_packet(T& t)
+{
+	static constexpr auto chunk_size = 1024; 
+	std::array<uint8_t, chunk_size> buffer;
+	std::vector<uint8_t> payload;
+
+	int ret, flush;
+	z_stream strm;
+
+	auto raw_payload = encode_raw_packet(t);
+
+	strm.zalloc = Z_NULL;
+	strm.zfree = Z_NULL;
+	strm.opaque = Z_NULL;
+	ret = deflateInit(&strm, 15);
+	if (ret != Z_OK)
+		throw std::runtime_error("deflate init error");
+
+	strm.avail_in = raw_payload.size();
+	strm.next_in = raw_payload.data();
+	do {
+		strm.avail_out = chunk_size;
+		strm.next_out = reinterpret_cast<Bytef *>(buffer.data());
+		ret = deflate(&strm, flush);
+		assert(ret != Z_STREAM_ERROR);
+		payload.insert(payload.end(), buffer.begin(), buffer.end()-strm.avail_out);
+	} while (strm.avail_out == 0);
+
+	assert(strm.avail_in == 0); /* all input will be used */
+
+	deflateEnd(&strm);
+	return payload;
+}
+}
+
+}
\ No newline at end of file
-- 
cgit v1.2.3