From e933ccb59c7f032d2ffc5c5f7046317a06e85e14 Mon Sep 17 00:00:00 2001
From: "Claudius \"keldu\" Holeksa" <mail@keldu.de>
Date: Tue, 17 Oct 2023 02:30:52 +0200
Subject: codec,codec-minecraft: Adding basic foundations needed for the
 minecraft protocol

---
 c++/codec-minecraft/.nix/derivation.nix |  32 +++++++++
 c++/codec-minecraft/SConscript          |  38 +++++++++++
 c++/codec-minecraft/SConstruct          |  66 ++++++++++++++++++
 c++/codec-minecraft/minecraft.h         | 116 ++++++++++++++++++++++++++++++++
 c++/codec-minecraft/var_int_data.cpp    |  36 ++++++++++
 c++/codec-minecraft/var_int_data.h      |  31 +++++++++
 c++/codec/schema.h                      |  15 ++++-
 7 files changed, 331 insertions(+), 3 deletions(-)
 create mode 100644 c++/codec-minecraft/.nix/derivation.nix
 create mode 100644 c++/codec-minecraft/SConscript
 create mode 100644 c++/codec-minecraft/SConstruct
 create mode 100644 c++/codec-minecraft/minecraft.h
 create mode 100644 c++/codec-minecraft/var_int_data.cpp
 create mode 100644 c++/codec-minecraft/var_int_data.h

(limited to 'c++')

diff --git a/c++/codec-minecraft/.nix/derivation.nix b/c++/codec-minecraft/.nix/derivation.nix
new file mode 100644
index 0000000..7704d13
--- /dev/null
+++ b/c++/codec-minecraft/.nix/derivation.nix
@@ -0,0 +1,32 @@
+{ lib
+, stdenvNoCC
+, scons
+, clang
+, clang-tools
+, version
+, forstio
+}:
+
+let
+
+in stdenvNoCC.mkDerivation {
+  pname = "forstio-codec-minecraft";
+  inherit version;
+  src = ./..;
+
+  enableParallelBuilding = true;
+
+  nativeBuildInputs = [
+    scons
+    clang
+    clang-tools
+  ];
+
+  buildInputs = [
+    forstio.core
+    forstio.async
+    forstio.codec
+  ];
+
+  outputs = ["out" "dev"];
+}
diff --git a/c++/codec-minecraft/SConscript b/c++/codec-minecraft/SConscript
new file mode 100644
index 0000000..4d1deab
--- /dev/null
+++ b/c++/codec-minecraft/SConscript
@@ -0,0 +1,38 @@
+#!/bin/false
+
+import os
+import os.path
+import glob
+
+
+Import('env')
+
+dir_path = Dir('.').abspath
+
+# Environment for base library
+codec_minecraft_env = env.Clone();
+
+codec_minecraft_env.sources = sorted(glob.glob(dir_path + "/*.cpp"))
+codec_minecraft_env.headers = sorted(glob.glob(dir_path + "/*.h"))
+
+env.sources += codec_minecraft_env.sources;
+env.headers += codec_minecraft_env.headers;
+
+## Shared lib
+objects_shared = []
+codec_minecraft_env.add_source_files(objects_shared, codec_minecraft_env.sources, shared=True);
+codec_minecraft_env.library_shared = codec_minecraft_env.SharedLibrary('#build/forstio-codec-minecraft', [objects_shared]);
+
+## Static lib
+objects_static = []
+codec_minecraft_env.add_source_files(objects_static, codec_minecraft_env.sources, shared=False);
+codec_minecraft_env.library_static = codec_minecraft_env.StaticLibrary('#build/forstio-codec-minecraft', [objects_static]);
+
+# Set Alias
+env.Alias('library_codec_minecraft', [codec_minecraft_env.library_shared, codec_minecraft_env.library_static]);
+
+env.targets += ['library_codec_minecraft'];
+
+# Install
+env.Install('$prefix/lib/', [codec_minecraft_env.library_shared, codec_minecraft_env.library_static]);
+env.Install('$prefix/include/forstio/codec/minecraft/', [codec_minecraft_env.headers]);
diff --git a/c++/codec-minecraft/SConstruct b/c++/codec-minecraft/SConstruct
new file mode 100644
index 0000000..edd5f57
--- /dev/null
+++ b/c++/codec-minecraft/SConstruct
@@ -0,0 +1,66 @@
+#!/usr/bin/env python3
+
+import sys
+import os
+import os.path
+import glob
+import re
+
+
+if sys.version_info < (3,):
+    def isbasestring(s):
+        return isinstance(s,basestring)
+else:
+    def isbasestring(s):
+        return isinstance(s, (str,bytes))
+
+def add_kel_source_files(self, sources, filetype, lib_env=None, shared=False, target_post=""):
+
+    if isbasestring(filetype):
+        dir_path = self.Dir('.').abspath
+        filetype = sorted(glob.glob(dir_path+"/"+filetype))
+
+    for path in filetype:
+        target_name = re.sub( r'(.*?)(\.cpp|\.c\+\+)', r'\1' + target_post, path )
+        if shared:
+            target_name+='.os'
+            sources.append( self.SharedObject( target=target_name, source=path ) )
+        else:
+            target_name+='.o'
+            sources.append( self.StaticObject( target=target_name, source=path ) )
+    pass
+
+def isAbsolutePath(key, dirname, env):
+	assert os.path.isabs(dirname), "%r must have absolute path syntax" % (key,)
+
+env_vars = Variables(
+	args=ARGUMENTS
+)
+
+env_vars.Add('prefix',
+	help='Installation target location of build results and headers',
+	default='/usr/local/',
+	validator=isAbsolutePath
+)
+
+env=Environment(ENV=os.environ, variables=env_vars, CPPPATH=[],
+    CPPDEFINES=['SAW_UNIX'],
+    CXXFLAGS=['-std=c++20','-g','-Wall','-Wextra'],
+    LIBS=['forstio-codec'])
+env.__class__.add_source_files = add_kel_source_files
+env.Tool('compilation_db');
+env.cdb = env.CompilationDatabase('compile_commands.json');
+
+env.objects = [];
+env.sources = [];
+env.headers = [];
+env.targets = [];
+
+Export('env')
+SConscript('SConscript')
+
+env.Alias('cdb', env.cdb);
+env.Alias('all', [env.targets]);
+env.Default('all');
+
+env.Alias('install', '$prefix')
diff --git a/c++/codec-minecraft/minecraft.h b/c++/codec-minecraft/minecraft.h
new file mode 100644
index 0000000..670b019
--- /dev/null
+++ b/c++/codec-minecraft/minecraft.h
@@ -0,0 +1,116 @@
+#pragma once
+
+#include <forstio/core/error.h>
+#include <forstio/codec/data.h>
+#include <forstio/codec/stream_value.h>
+
+namespace saw {
+namespace encode {
+struct Minecraft {};
+struct VarIntTransport {};
+}
+
+template<typename T>
+class data<T, encode::Minecraft> {
+private:
+	ring_buffer buffer_;
+public:
+	data() = default;
+	data(std::size_t size):
+		buffer_{size}
+	{}
+
+	buffer& get_buffer(){
+		return buffer_;
+	}
+};
+
+namespace mc {
+namespace impl {
+union minecraft_signed_four_conversion {
+		int32_t s;
+		uint32_t u;
+};
+
+union minecraft_signed_eight_conversion {
+		int64_t s;
+		uint64_t u;
+};
+
+template<typename Schema, typename FromEnc>
+class minecraft_encode {
+	static_assert(always_false<Schema, FromEnc>, "This schema type is not being handled by the Minecraft encoding.");
+};
+
+template<typename FromEnc>
+class minecraft_encode<schema::VarInt, FromEnc>{
+	static error_or<void> encode(const data<schema::VarInt, FromEnc>& from, buffer& to){
+		uint8_t encode_index = 0;
+		minecraft_signed_four_conversion value;
+		value.s = from.get();
+
+		/**
+		 * VarInt max length is 5 bytes
+		 */
+		std::array<uint8_t, 5> encode_data;
+
+		do {
+				uint8_t step = static_cast<uint8_t>(value.u & 0x7F);
+				value.u = value.u >> 7;
+				if(value.u != 0){
+						step |= 0x80;
+				}
+				encode_data[encode_index] = step;
+				++encode_index;
+		}while(value.u != 0);
+		
+		auto err = buffer.push(encode_data[0], encode_index);
+		if (!err.template is_type<err::no_error>()) {
+				return err;
+		}
+
+		return no_error();
+	}
+};
+
+template<typename Schema, typename FromEnc>
+class minecraft_decode {
+	static_assert(always_false<Schema, FromEnc>, "This schema type is not being handled by the Minecraft encoding.");
+};
+
+template<typename FromEnc>
+class minecraft_decode<schema::VarInt, FromEnc>{
+		static error_or<void> decode(buffer& from, data<schema::VarInt, FromEnc>& to){
+				uint8_t num_reads = 0;
+
+				minecraft_signed_four_conversion value;
+				value.u = 0;
+				
+				uint8_t read{};
+				do {
+						auto err = from.pop(read);
+						if( !err.template is_type<err::no_error>() ){
+								return err;
+						}
+						value.u |= ((read & 0x7F) << (7*num_reads));
+						++num_reads;
+						if(num_reads > 5){
+								return make_error<err::>();
+						}
+				} while( (read & 0x80) != 0);
+
+				to.set(value.s);
+
+				return no_error();
+		}
+};
+
+}
+}
+
+
+
+namespace mc {
+
+}
+}
diff --git a/c++/codec-minecraft/var_int_data.cpp b/c++/codec-minecraft/var_int_data.cpp
new file mode 100644
index 0000000..59e4317
--- /dev/null
+++ b/c++/codec-minecraft/var_int_data.cpp
@@ -0,0 +1,36 @@
+#include "var_int_data.h"
+
+namespace saw {
+data<schema::VarInt,encode::Native>::data():
+		data_{}
+{}
+
+data<schema::VarInt,encode::Native>::data(int32_t data):
+		data_{data}
+{}
+
+int32_t data<schema::VarInt, encode::Native>::get() const {
+		return data_;
+}
+
+void data<schema::VarInt, encode::Native>::set(int32_t data) {
+		data_ = data;
+}
+
+data<schema::VarLong,encode::Native>::data():
+		data_{}
+{}
+
+data<schema::VarLong,encode::Native>::data(int64_t data):
+		data_{data}
+{}
+
+int64_t data<schema::VarLong, encode::Native>::get() const {
+		return data_;
+}
+
+void data<schema::VarLong, encode::Native>::set(int64_t data) {
+		data_ = data;
+}
+
+}
diff --git a/c++/codec-minecraft/var_int_data.h b/c++/codec-minecraft/var_int_data.h
new file mode 100644
index 0000000..807c930
--- /dev/null
+++ b/c++/codec-minecraft/var_int_data.h
@@ -0,0 +1,31 @@
+#pragma once
+
+#include <forstio/core/data.h>
+
+namespace saw {
+template<>
+class data<schema::VarInt, encode::Native> {
+private:
+		int32_t data_;
+public:
+		data();
+		data(int32_t data);
+
+		int32_t get() const;
+		void set(int32_t);
+};
+
+template<>
+class data<schema::VarLong, encode::Native> {
+private:
+		int64_t data_;
+public:
+		data();
+		data(int64_t data);
+
+		int64_t get() const;
+		void set(int64_t);
+};
+
+
+}
diff --git a/c++/codec/schema.h b/c++/codec/schema.h
index ba6dd4c..a8494fe 100644
--- a/c++/codec/schema.h
+++ b/c++/codec/schema.h
@@ -80,10 +80,19 @@ using UInt64 = Primitive<UnsignedInteger, 8>;
 using Float32 = Primitive<FloatingPoint, 4>;
 using Float64 = Primitive<FloatingPoint, 8>;
 
+/**
+ * Classes allowing to distinguish Ints from VarInts
+ */
+template<typename T, std::size_t MaxLen>
+struct VariableLengthPrimitive {};
+
+using VarInt = VariableLengthPrimitive<SignedInteger, 5>;
+using VarLong = VariableLengthPrimitive<SignedInteger, 10>;
+
 /**
  * Classes enabling Rpc calls
  */
-template <class Request, class Response, string_literal Literal>
+template <class Request, class Response>
 struct Function {};
 
 template <class... T> struct Interface {
@@ -92,8 +101,8 @@ template <class... T> struct Interface {
 		"This schema template doesn't support this type of template argument");
 };
 
-template <class... Request, class... Response, string_literal... Literal>
-struct Interface<Function<Request, Response, Literal>...> {};
+template <class... Requests, class... Responses, string_literal... Names>
+struct Interface<Member<Function<Requests, Responses>,Names>...> {};
 
 // NOLINTEND
 } // namespace schema
-- 
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