grap version 3 from https://github.com/Green-Sky/crdt_tests/

.github/FUNDING.yml

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+github: Green-Sky

.github/workflows/ci.yml

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+name: ContinuousIntegration
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+env:
+  BUILD_TYPE: Debug
+
+jobs:
+  linux:
+    timeout-minutes: 10
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v3
+      with:
+        submodules: recursive
+
+    - name: Configure CMake
+      run: cmake -B ${{github.workspace}}/build -DCMAKE_BUILD_TYPE=${{env.BUILD_TYPE}}
+
+    - name: Build
+      run: cmake --build ${{github.workspace}}/build --config ${{env.BUILD_TYPE}} -j 4
+
+    - name: Test
+      run: ctest --test-dir ${{github.workspace}}/build -C ${{env.BUILD_TYPE}} --verbose
+
+  macos:
+    timeout-minutes: 10
+
+    runs-on: macos-latest
+
+    steps:
+    - uses: actions/checkout@v3
+      with:
+        submodules: recursive
+
+    - name: Install Dependencies
+      run: brew install libsodium
+
+    - name: Configure CMake
+      run: cmake -B ${{github.workspace}}/build -DCMAKE_BUILD_TYPE=${{env.BUILD_TYPE}}
+
+    - name: Build
+      run: cmake --build ${{github.workspace}}/build --config ${{env.BUILD_TYPE}} -j 3
+
+    - name: Test
+      run: ctest --test-dir ${{github.workspace}}/build -C ${{env.BUILD_TYPE}} --verbose
+
+  windows:
+    timeout-minutes: 10
+
+    runs-on: windows-latest
+
+    steps:
+    - uses: actions/checkout@v3
+      with:
+        submodules: recursive
+
+    # setup vs env
+    - uses: ilammy/msvc-dev-cmd@v1
+      with:
+        arch: amd64
+
+    - name: Configure CMake
+      run: cmake -G Ninja -B ${{github.workspace}}/build -DCMAKE_BUILD_TYPE=${{env.BUILD_TYPE}}
+
+    - name: Build
+      run: cmake --build ${{github.workspace}}/build --config ${{env.BUILD_TYPE}} -j 3
+
+    - name: Test
+      run: ctest --test-dir ${{github.workspace}}/build -C ${{env.BUILD_TYPE}} --verbose
+

.gitignore

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+.vs/
+*.o
+*.swp
+~*
+*~
+.idea/
+cmake-build-debug/
+cmake-build-debugandtest/
+cmake-build-release/
+*.stackdump
+*.coredump
+compile_commands.json
+/build*
+/result*
+.clangd
+.cache
+
+.DS_Store
+.AppleDouble
+.LSOverride
+
+CMakeLists.txt.user*
+CMakeCache.txt
+
+*.tox
+imgui.ini

CMakeLists.txt

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+cmake_minimum_required(VERSION 3.24 FATAL_ERROR)
+
+# cmake setup begin
+project(green_crdt)
+
+if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
+	set(GREEN_CRDT_STANDALONE ON)
+	# why the f do i need this >:(
+	set(NOT_GREEN_CRDT_STANDALONE OFF)
+else()
+	set(GREEN_CRDT_STANDALONE OFF)
+	set(NOT_GREEN_CRDT_STANDALONE ON)
+endif()
+message("II GREEN_CRDT_STANDALONE " ${GREEN_CRDT_STANDALONE})
+
+if (GREEN_CRDT_STANDALONE)
+	set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+
+	# defaulting to debug mode, if not specified
+	if(NOT CMAKE_BUILD_TYPE)
+		set(CMAKE_BUILD_TYPE "Debug")
+	endif()
+
+	# setup my vim ycm :D
+	set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
+	# more paths
+	set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/lib")
+	set(CMAKE_LIBRARY_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/bin")
+	set(CMAKE_RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/bin")
+endif()
+
+if (GREEN_CRDT_STANDALONE)
+	include(CTest)
+
+	set(CMAKE_CXX_EXTENSIONS OFF)
+
+	# bump up warning levels appropriately for clang, gcc & msvc
+	if (${CMAKE_CXX_COMPILER_ID} STREQUAL "GNU" OR ${CMAKE_CXX_COMPILER_ID} STREQUAL "Clang")
+		add_compile_options(
+			-Wall -Wextra # Reasonable and standard
+			-Wpedantic # Warn if non-standard C++ is used
+			-Wunused # Warn on anything being unused
+			#-Wconversion # Warn on type conversions that may lose data
+			#-Wsign-conversion # Warn on sign conversions
+			-Wshadow # Warn if a variable declaration shadows one from a parent context
+		)
+
+		if (NOT WIN32)
+			#link_libraries(-fsanitize=address,undefined)
+			#link_libraries(-fsanitize=undefined)
+		endif()
+	elseif (${CMAKE_CXX_COMPILER_ID} STREQUAL "MSVC")
+		if (CMAKE_CXX_FLAGS MATCHES "/W[0-4]")
+			string(REGEX REPLACE "/W[0-4]" "/W4" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
+		else()
+			set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /W4")
+		endif()
+	endif()
+
+endif()
+
+# cmake setup end
+
+add_subdirectory(./version3)
+

version3/CMakeLists.txt

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+cmake_minimum_required(VERSION 3.9 FATAL_ERROR)
+
+project(crdt_version3 CXX C)
+
+add_library(crdt_version3 INTERFACE)
+
+target_compile_features(crdt_version3 INTERFACE cxx_std_17)
+
+target_include_directories(crdt_version3 INTERFACE "${PROJECT_SOURCE_DIR}")
+
+########################################
+
+if (BUILD_TESTING AND GREEN_CRDT_STANDALONE)
+
+	add_executable(v3_test1
+		./test1.cpp
+	)
+	target_link_libraries(v3_test1 PUBLIC crdt_version3)
+	add_test(NAME v3_test1 COMMAND v3_test1)
+
+########################################
+
+	add_executable(v3_test2
+		./test2.cpp
+	)
+	target_link_libraries(v3_test2 PUBLIC crdt_version3)
+	add_test(NAME v3_test2 COMMAND v3_test2)
+
+endif()
+

version3/green_crdt/v3/list.hpp

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+#pragma once
+
+#include <cstdint>
+#include <optional>
+#include <unordered_map>
+#include <vector>
+#include <string>
+
+#include <cassert>
+
+#if !defined(extra_assert)
+	#if defined(EXTRA_ASSERTS) && EXTRA_ASSERTS == 1
+		#define extra_assert(...) assert(__VA_ARGS__)
+	#else
+		#define extra_assert(...) void(0)
+	#endif
+#endif
+
+namespace GreenCRDT::V3 {
+
+template<typename ValueType, typename ActorType>
+struct List {
+	// for public interface
+	struct ListID {
+		ActorType id;
+		uint64_t seq{0}; // strictly increasing for that actor
+
+		bool operator<(const ListID& rhs) const {
+			if (seq < rhs.seq) {
+				return true;
+			} else if (seq > rhs.seq) {
+				return false;
+			} else { // ==
+				return id < rhs.id;
+			}
+		}
+
+		bool operator==(const ListID& rhs) const {
+			return seq == rhs.seq && id == rhs.id;
+		}
+
+		bool operator!=(const ListID& rhs) const {
+			return seq != rhs.seq || id != rhs.id;
+		}
+	};
+
+	struct ListIDInternal {
+		size_t actor_idx{0};
+		uint64_t seq{0}; // strictly increasing for that actor
+
+		bool operator==(const ListIDInternal& rhs) const {
+			return seq == rhs.seq && actor_idx == rhs.actor_idx;
+		}
+	};
+
+	// internally the index into this array is used to refer to an actor
+	std::vector<ActorType> _actors;
+
+	struct Entry_Data {
+		// Yjs
+		std::optional<ListIDInternal> parent_left;
+		std::optional<ListIDInternal> parent_right;
+
+		// might be deleted (yes, *sigh*, crtds need tombstones)
+		std::optional<ValueType> value;
+	};
+
+	std::vector<ListIDInternal> _list_ids;
+	std::vector<Entry_Data> _list_data;
+
+	// number of not deleted entries
+	size_t _doc_size {0};
+
+	// TODO: actor index instead of map
+	std::unordered_map<size_t, uint64_t> _last_seen_seq;
+
+	// caching only, contains the last index an actor inserted at
+	std::unordered_map<size_t, size_t> _last_inserted_idx;
+
+	//size_t _stat_find_with_hint{0};
+	//size_t _stat_find_with_hint_hit{0};
+
+	[[nodiscard]] std::optional<size_t> findActor(const ActorType& actor) const {
+		for (size_t i = 0; i < _actors.size(); i++) {
+			if (_actors[i] == actor) {
+				return i;
+			}
+		}
+		return std::nullopt;
+	}
+
+	[[nodiscard]] std::optional<size_t> findIdx(const ListIDInternal& list_id) const {
+		extra_assert(verify());
+
+		for (size_t i = 0; i < _list_ids.size(); i++) {
+			if (_list_ids[i] == list_id) {
+				return i;
+			}
+		}
+
+		return std::nullopt;
+	}
+
+	// search close to hint first
+	[[nodiscard]] std::optional<size_t> findIdx(const ListIDInternal& list_id, size_t hint) const {
+		extra_assert(verify());
+
+		//_stat_find_with_hint++;
+
+		// TODO: find some good magic values here
+		// total: 364150
+		// 2-9 hits: 360164 (3m54)
+		// 1-9 hits: 360161 (3m53)
+		// 1-2 hits: 359800 (3m55s)
+		// 0-2 hits: 359763 (3m54s)
+		// changed from loop to single if:
+		// 1-2 hits: 359800 (3m50s)
+		// 1-4 hits: 359928 (3m51s) (after cond reorder: 3m49s)
+		static constexpr size_t c_hint_pre = 1;
+		static constexpr size_t c_hint_post = 4;
+
+		{ // go back 2, so we dont miss // TODO: is this really needed
+			//for (size_t i = 0; hint > 0 && i < c_hint_pre; hint--, i++) {}
+			if (hint >= c_hint_pre) {
+				hint -= c_hint_pre;
+			}
+		}
+
+		const size_t max_at_hint = hint + c_hint_post; // how many positions we check at hint, before falling back to full lookup
+
+		for (size_t i = hint; i <= max_at_hint && i < _list_ids.size(); i++) {
+			if (_list_ids[i] == list_id) {
+				//_stat_find_with_hint_hit++;
+				return i;
+			}
+		}
+
+		// fall back to normal search
+		// TODO: in some cases we scan the list twice now!!
+		return findIdx(list_id);
+	}
+
+	[[nodiscard]] std::optional<size_t> findIdx(const ListID& list_id) const {
+		extra_assert(verify());
+
+		const auto actor_idx_opt = findActor(list_id.id);
+		if (!actor_idx_opt.has_value()) {
+			return std::nullopt;
+		}
+
+		const ListIDInternal tmp_id {actor_idx_opt.value(), list_id.seq};
+
+		return findIdx(tmp_id);
+	}
+
+	[[nodiscard]] std::optional<size_t> findIdx(const ListID& list_id, size_t hint) const {
+		extra_assert(verify());
+
+		const auto actor_idx_opt = findActor(list_id.id);
+		if (!actor_idx_opt.has_value()) {
+			return std::nullopt;
+		}
+
+		const ListIDInternal tmp_id {actor_idx_opt.value(), list_id.seq};
+
+		return findIdx(tmp_id, hint);
+	}
+
+	// returns false if missing OPs
+	// based on YjsMod https://github.com/josephg/reference-crdts/blob/9f4f9c3a97b497e2df8ae4473d1e521d3c3bf2d2/crdts.ts#L293-L348
+	// which is a modified Yjs(YATA) algo
+	// TODO: idx_hint
+	bool add(const ListID& list_id, const ValueType& value, const std::optional<ListID>& parent_left, const std::optional<ListID>& parent_right) {
+		extra_assert(verify());
+
+		size_t actor_idx {0};
+		{ // new actor?
+			// add, even if op fails
+			const auto actor_opt = findActor(list_id.id);
+			if (!actor_opt.has_value()) {
+				actor_idx = _actors.size();
+				_last_inserted_idx[_actors.size()] = 0; // hack
+				_actors.push_back(list_id.id);
+			} else {
+				actor_idx = actor_opt.value();
+			}
+		}
+
+		// check actor op order
+		if (!_last_seen_seq.count(actor_idx)) {
+			// we dont know this actor yet, first seq needs to be 0
+			if (list_id.seq != 0) {
+				return false;
+			}
+		} else {
+			// making sure we dont skip operations by that actor
+			if (list_id.seq != _last_seen_seq.at(actor_idx) + 1) {
+				return false;
+			}
+		}
+
+		size_t insert_idx = 0;
+		if (_list_ids.empty()) {
+			if (parent_left.has_value() || parent_right.has_value()) {
+				// empty, missing parents
+				return false;
+			}
+		} else {
+			// find left
+			std::optional<size_t> left_idx_opt = std::nullopt;
+			if (parent_left.has_value()) {
+				left_idx_opt = findIdx(parent_left.value(), _last_inserted_idx[actor_idx]);
+				if (!left_idx_opt.has_value()) {
+					// missing parent left
+					return false;
+				}
+
+				// we insert before the it, so we need to go past the left parent
+				insert_idx = left_idx_opt.value() + 1;
+			} // else insert_idx = 0
+			const size_t left_idx_hint = insert_idx;
+
+			// find right
+			size_t right_idx = _list_ids.size();
+			if (parent_right.has_value()) {
+				auto tmp_right = findIdx(parent_right.value(), left_idx_hint);
+				if (!tmp_right.has_value()) {
+					return false;
+				}
+				right_idx = tmp_right.value();
+			}
+
+			bool scanning {false};
+
+			for(size_t i = insert_idx;; i++) {
+				if (!scanning) {
+					insert_idx = i;
+				}
+				// if right parent / end of doc, insert
+				if (insert_idx == right_idx) {
+					break;
+				}
+				// we ran past right o.o ?
+				if (insert_idx == _list_ids.size()) {
+					break;
+				}
+
+				const Entry_Data& at_i = _list_data[i];
+				// parents left and right
+				std::optional<size_t> i_left_idx {std::nullopt};
+				if (at_i.parent_left.has_value()) {
+					i_left_idx = findIdx(at_i.parent_left.value(), left_idx_hint);
+					if (!i_left_idx.has_value()) {
+						assert(false && "item in list with unknown parent left!!");
+						return false;
+					}
+				}
+
+				// possibility map
+				//
+				//         | ir < r | ir == r       | ir > r
+				// -------------------------------------
+				// il < l  | insert | insert        | insert
+				// il == l | ?      | agentfallback | ?
+				// il > l  | skip   | skip          | skip
+
+				if (i_left_idx < left_idx_opt) {
+					break;
+				} else if (i_left_idx == left_idx_opt) {
+					// get i parent_right
+					size_t i_right_idx = _list_ids.size();
+					if (at_i.parent_right.has_value()) {
+						auto tmp_right = findIdx(at_i.parent_right.value(), insert_idx);
+						if (!tmp_right.has_value()) {
+							assert(false && "item in list with unknown parent right!!");
+							return false;
+						}
+						i_right_idx = tmp_right.value();
+					}
+
+					if (i_right_idx < right_idx) {
+						scanning = true;
+					} else if (i_right_idx == right_idx) {
+						// actor id tie breaker
+						if (_actors[actor_idx] < _actors[_list_ids[i].actor_idx]) {
+							break;
+						} else {
+							scanning = false;
+						}
+					} else { // i_right_idx > right_idx
+						scanning = false;
+					}
+				} else { // il > l
+					// do nothing
+				}
+			}
+		}
+
+		{ // actual insert
+			_list_ids.emplace(_list_ids.begin() + insert_idx, ListIDInternal{actor_idx, list_id.seq});
+
+			Entry_Data new_entry;
+			if (parent_left.has_value()) {
+				new_entry.parent_left = ListIDInternal{findActor(parent_left.value().id).value(), parent_left.value().seq};
+			}
+
+			if (parent_right.has_value()) {
+				new_entry.parent_right = ListIDInternal{findActor(parent_right.value().id).value(), parent_right.value().seq};
+			}
+
+			new_entry.value = value;
+
+			_list_data.emplace(_list_data.begin() + insert_idx, new_entry);
+			_last_inserted_idx[actor_idx] = insert_idx;
+		}
+
+		_doc_size++;
+		_last_seen_seq[actor_idx] = list_id.seq;
+
+		extra_assert(verify());
+		return true;
+	}
+
+	// returns false if not found
+	bool del(const ListID& id) {
+		extra_assert(verify());
+
+		auto actor_idx_opt = findActor(id.id);
+		if (!actor_idx_opt.has_value()) {
+			// we dont have anything with that actor
+			return false;
+		}
+
+#if 0
+		const ListIDInternal tmp_id {actor_idx_opt.value(), id.seq};
+		for (auto& it : list) {
+			if (it.id == tmp_id) {
+				if (it.value.has_value()) {
+					it.value.reset();
+
+					doc_size--;
+					extra_assert(verify());
+					return true;
+				} else {
+					extra_assert(verify());
+					return false; // TODO: allow double deletes?,,,, need ids
+				}
+			}
+		}
+#endif
+		// TODO: actually test deletes lol
+		const auto idx_opt = findIdx(id);
+		if (idx_opt.has_value()) {
+			auto& it = _list_data[idx_opt.value()];
+			if (it.value.has_value()) {
+				it.value.reset();
+
+				_doc_size--;
+				extra_assert(verify());
+				return true;
+			} else {
+				extra_assert(verify());
+				return false; // TODO: allow double deletes?,,,, need ids
+			}
+		}
+
+		// not found
+		extra_assert(verify());
+		return false;
+	}
+
+	[[nodiscard]] bool empty(void) const {
+		return _list_ids.empty();
+	}
+
+	[[nodiscard]] size_t size(void) const {
+		return _list_ids.size();
+	}
+
+	[[nodiscard]] ListIDInternal getIDInternal(size_t idx) const {
+		return _list_ids.at(idx);
+	}
+
+	[[nodiscard]] const ListID getID(size_t idx) const {
+		return {_actors.at(_list_ids.at(idx).actor_idx), _list_ids.at(idx).seq};
+	}
+
+	[[nodiscard]] const std::optional<ValueType>& getValue(size_t idx) const {
+		return _list_data.at(idx).value;
+	}
+
+	// returns the size of alive entries
+	[[nodiscard]] size_t getDocSize(void) const {
+		return _doc_size;
+	}
+
+	[[nodiscard]] std::vector<ValueType> getArray(void) const {
+		std::vector<ValueType> array;
+		for (const auto& e : _list_data) {
+			if (e.value.has_value()) {
+				array.push_back(e.value.value());
+			}
+		}
+
+		return array;
+	}
+
+	// TODO: only in debug?
+	bool verify(void) const {
+		if (_list_ids.size() != _list_data.size()) {
+			return false;
+		}
+
+		size_t actual_size = 0;
+		for (const auto& it : _list_data) {
+			if (it.value.has_value()) {
+				actual_size++;
+			}
+		}
+		//assert(doc_size == actual_size);
+		return _doc_size == actual_size;
+	}
+};
+
+} // GreenCRDT::V3
+

version3/green_crdt/v3/text_document.hpp

@@ -0,0 +1,305 @@
+#pragma once
+
+#include "./list.hpp"
+
+#include <variant>
+
+//#include <iostream> // debug
+
+namespace GreenCRDT::V3 {
+
+template<typename ActorType>
+struct TextDocument {
+	// TODO: determine if char is the best
+	using ListType = List<char, ActorType>;
+
+	struct OpAdd {
+		typename ListType::ListID id;
+
+		std::optional<typename ListType::ListID> parent_left;
+		std::optional<typename ListType::ListID> parent_right;
+
+		char value;
+	};
+
+	struct OpDel {
+		typename ListType::ListID id;
+	};
+
+	using Op = std::variant<OpAdd, OpDel>;
+
+	//// TODO: implement
+	//struct Cursor {
+		//AgentType who;
+		//typename ListType::ListID pos;
+	//};
+
+	ActorType local_actor;
+
+	ListType state;
+
+	[[nodiscard]] std::string getText(void) const {
+		std::string text;
+
+		for (const auto& it : state._list_data) {
+			if (it.value.has_value()) {
+				text += it.value.value();
+			}
+		}
+
+		return text;
+	}
+
+	bool apply(const Op& op) {
+		if(std::holds_alternative<OpAdd>(op)) {
+			const auto& add_op = std::get<OpAdd>(op);
+			//std::cout << "a:" << add_op.id.id << " s:" << add_op.id.seq << " v:" << add_op.value << "\n";
+			return state.add(add_op.id, add_op.value, add_op.parent_left, add_op.parent_right);
+		} else if (std::holds_alternative<OpDel>(op)) {
+			const auto& del_op = std::get<OpDel>(op);
+			return state.del(del_op.id);
+		} else {
+			assert(false);
+		}
+	}
+
+	bool apply(const std::vector<Op>& ops) {
+		for (const auto& op : ops) {
+			if (!apply(op)) {
+				// this is not ideal, since we might have applyed some, and dont report which/howmany
+				return false;
+			}
+		}
+
+		return true;
+	}
+
+	static std::vector<Op> text2adds(
+		const ActorType& actor, uint64_t seq, // seq is the first seq
+		std::optional<typename ListType::ListID> parent_left,
+		std::optional<typename ListType::ListID> parent_right,
+		std::string_view text
+	) {
+		std::vector<Op> ops;
+		for (size_t i = 0; i < text.size(); i++) {
+			typename ListType::ListID new_id {actor, seq++};
+
+			ops.emplace_back(OpAdd{
+				new_id,
+				parent_left,
+				parent_right,
+				text[i]
+			});
+
+			parent_left = new_id;
+		}
+
+		return ops;
+	}
+
+	// adds in tast with specified parents
+	// returns generated ops
+	std::vector<Op> addText(
+		std::optional<typename ListType::ListID> parent_left,
+		std::optional<typename ListType::ListID> parent_right,
+		std::string_view text
+	) {
+		// TODO: move actor setting to list
+		if (!state.findActor(local_actor).has_value()) {
+			state._actors.push_back(local_actor);
+		}
+
+		// TODO: look up typesystem and fix (move? decltype?)
+		std::vector<Op> ops = text2adds(
+			// TODO: abstract actors
+			local_actor, state._last_seen_seq.count(state.findActor(local_actor).value()) ? state._last_seen_seq[state.findActor(local_actor).value()]+1u : 0u,
+			parent_left,
+			parent_right,
+			text
+		);
+
+		// TODO: make this better
+		// and apply
+		for (const auto& op : ops) {
+			if(std::holds_alternative<OpAdd>(op)) {
+				const auto& add_op = std::get<OpAdd>(op);
+				//std::cout << "a:" << add_op.id.id << " s:" << add_op.id.seq << " v:" << add_op.value << "\n";
+				bool r = state.add(add_op.id, add_op.value, add_op.parent_left, add_op.parent_right);
+				assert(r);
+			} else if (std::holds_alternative<OpDel>(op)) {
+				const auto& del_op = std::get<OpDel>(op);
+				state.del(del_op.id);
+			} else {
+				assert(false);
+			}
+		}
+
+		return ops; // TODO: move?
+	}
+
+	// deletes everything in range [first, last)
+	// returns generated ops
+	std::vector<Op> delRange(
+		std::optional<typename ListType::ListID> left,
+		std::optional<typename ListType::ListID> right
+	) {
+		size_t first_idx = 0;
+		if (left.has_value()) {
+			auto res = state.findIdx(left.value());
+			if (!res.has_value()) {
+				assert(false && "cant find left");
+				return {};
+			}
+			first_idx = res.value();
+		}
+
+		size_t last_idx = state.size();
+		if (right.has_value()) {
+			auto res = state.findIdx(right.value());
+			if (!res.has_value()) {
+				assert(false && "cant find right");
+				return {};
+			}
+			last_idx = res.value();
+		}
+
+		std::vector<Op> ops;
+
+		for (size_t i = first_idx; i < last_idx; i++) {
+			if (!state.getValue(i).has_value()) {
+				// allready deleted
+				continue;
+			}
+
+			ops.emplace_back(OpDel{
+				//state.list.at(i).id
+				state.getID(i)
+			});
+
+			// TODO: do delets get a seq?????
+
+			state.del(state.getID(i));
+		}
+
+		return ops;
+	}
+
+	// generates ops from the difference
+	// note: rn it only creates 1 diff patch
+	std::vector<Op> merge(std::string_view text) {
+		if (text.empty()) {
+			if (state.empty() || state.getDocSize() == 0) {
+				// no op
+				return {};
+			} else {
+				// delete all
+				return delRange(std::nullopt, std::nullopt);
+			}
+		}
+		// text not empty
+
+		if (state.empty()) {
+			return addText(
+				std::nullopt,
+				std::nullopt,
+				text
+			);
+		}
+		// neither empty
+
+		// find start and end of changes
+		// start
+		size_t list_start = 0;
+		size_t list_start_counted = 0;
+		size_t text_start = 0;
+		bool differ = false;
+		for (; list_start < state.size() && text_start < text.size();) {
+			// jump over tombstones
+			if (!state.getValue(list_start).has_value()) {
+				list_start++;
+				continue;
+			}
+
+			if (state.getValue(list_start).value() != text[text_start]) {
+				differ = true;
+				break;
+			}
+
+			list_start++;
+			text_start++;
+			list_start_counted++;
+		}
+
+		// doc and text dont differ
+		if (!differ && list_start == state.size() && text_start == text.size()) {
+			return {};
+		}
+		//std::cout << "list.size: " << state.list.size() << "(" << getText().size() << ")" << " text.size: " << text.size() << "\n";
+		//std::cout << "list_start: " << list_start << " text_start: " << text_start << "\n";
+
+		// +1 so i can have unsigned
+		size_t list_end = state.size();
+		size_t text_end = text.size();
+		//for (; list_end > 0 && text_end > 0 && list_end >= list_start && text_end >= text_start;) {
+		//while (list_end >= list_start && text_end >= text_start) {
+		size_t list_end_counted = 0;
+		differ = false; // var reuse
+		//while (list_start_counted - list_end_counted > state.doc_size && text_end >= text_start) {
+		while (state.getDocSize() - list_start_counted > list_end_counted && text_end >= text_start) {
+			// jump over tombstones
+			if (!state.getValue(list_end-1).has_value()) {
+				list_end--;
+				continue;
+			}
+
+			if (state.getValue(list_end-1).value() != text[text_end-1]) {
+				differ = true;
+				break;
+			}
+
+			list_end--;
+			text_end--;
+			list_end_counted++;
+		}
+
+		if (!differ && text_start == text_end+1) {
+			// we ran into eachother without seeing the different char
+			// TODO: do we need to increment list_end? text_end?
+			list_end++;
+		}
+
+		//std::cout << "list_end: " << list_end << " text_end: " << text_end << "\n";
+		//std::cout << "substring before: " << text.substr(text_start, text.size() - state.doc_size) << "\n";
+
+		std::vector<Op> ops;
+
+		// 1. clear range (del all list_start - list_end)
+		if (list_start <= list_end && list_start < state.size()) {
+			//list_end += list_start == list_end;
+			ops = delRange(
+				state.getID(list_start),
+				list_end < state.size() ? std::make_optional(state.getID(list_end)) : std::nullopt
+			);
+			//std::cout << "deleted: " << ops.size() << "\n";
+		}
+
+		//std::cout << "text between: " << getText() << "\n";
+		//std::cout << "substring between: " << text.substr(text_start, text.size() - state.doc_size) << "\n";
+
+		// 2. add range (add all text_start - text_end)
+		if (state.getDocSize() < text.size()) {
+			auto tmp_add_ops = addText(
+				list_start == 0 ? std::nullopt : std::make_optional(state.getID(list_start-1)),
+				list_start == state.size() ? std::nullopt :std::make_optional(state.getID(list_start)),
+				text.substr(text_start, text.size() - state.getDocSize())
+			);
+			//std::cout << "added: " << tmp_add_ops.size() << "\n";
+			ops.insert(ops.end(), tmp_add_ops.begin(), tmp_add_ops.end());
+		}
+
+		return ops;
+	}
+};
+
+} // GreenCRDT::V3
+

version3/test1.cpp

@@ -0,0 +1,214 @@
+#define EXTRA_ASSERTS 1
+#include <green_crdt/v3/list.hpp>
+
+#include <numeric>
+#include <random>
+#include <iostream>
+#include <cassert>
+#include <string_view>
+#include <vector>
+
+// single letter actor, for testing only
+using Actor = char;
+using ListType = GreenCRDT::V3::List<char, Actor>;
+
+namespace std {
+bool operator==(const std::vector<char>& lhs, const std::string_view& rhs) {
+	if (lhs.size() != rhs.size()) {
+		return false;
+	}
+
+	for (size_t i = 0; i < rhs.size(); i++) {
+		if (lhs[i] != rhs[i]) {
+			return false;
+		}
+	}
+
+	return true;
+}
+} // namespace std
+
+void testSingle1(void) {
+	ListType list;
+
+	assert(list.add({'A', 0}, 'a', std::nullopt, std::nullopt));
+	assert(list.add({'A', 1}, 'b', ListType::ListID{'A', 0u}, std::nullopt));
+
+	assert(list.getArray() == "ab");
+}
+
+
+void testConcurrent1(void) {
+	// agent_a < agent_b
+
+	// concurrent insert of first element
+	{ // variant 1, a then b
+		ListType list;
+		assert(list.add({'A', 0}, 'a', std::nullopt, std::nullopt));
+		assert(list.add({'B', 0}, 'b', std::nullopt, std::nullopt));
+
+		assert(list.getArray() == "ab");
+	}
+	{ // variant 2, b then a
+		ListType list;
+		assert(list.add({'B', 0}, 'b', std::nullopt, std::nullopt));
+		assert(list.add({'A', 0}, 'a', std::nullopt, std::nullopt));
+
+		assert(list.getArray() == "ab");
+	}
+}
+
+struct AddOp {
+	ListType::ListID id;
+	char value;
+	std::optional<ListType::ListID> parent_left;
+	std::optional<ListType::ListID> parent_right;
+};
+
+void randomAddPermutations(const std::vector<AddOp>& ops, const std::string& expected) {
+	// TODO: more then 1k?
+	for (size_t i = 0; i < 1000; i++) {
+		std::minstd_rand rng(1337 + i);
+		std::vector<size_t> ops_todo(ops.size());
+		std::iota(ops_todo.begin(), ops_todo.end(), 0u);
+
+		size_t attempts {0};
+
+		ListType list;
+		do {
+			size_t idx = rng() % ops_todo.size();
+
+			if (list.add(ops[ops_todo[idx]].id, ops[ops_todo[idx]].value, ops[ops_todo[idx]].parent_left, ops[ops_todo[idx]].parent_right)) {
+				// only remove if it was possible -> returned true;
+				ops_todo.erase(ops_todo.begin()+idx);
+			}
+
+			attempts++;
+			assert(attempts < 10'000); // in case we run into an endless loop
+		} while (!ops_todo.empty());
+
+		assert(list.getArray() == expected);
+	}
+}
+
+void testInterleave1(void) {
+	const std::vector<AddOp> ops {
+		{{'A', 0u}, 'a', std::nullopt, std::nullopt},
+		{{'A', 1u}, 'a', ListType::ListID{'A', 0u}, std::nullopt},
+		{{'A', 2u}, 'a', ListType::ListID{'A', 1u}, std::nullopt},
+		{{'B', 0u}, 'b', std::nullopt, std::nullopt},
+		{{'B', 1u}, 'b', ListType::ListID{'B', 0u}, std::nullopt},
+		{{'B', 2u}, 'b', ListType::ListID{'B', 1u}, std::nullopt},
+	};
+
+	randomAddPermutations(ops, "aaabbb");
+}
+
+void testInterleave2(void) {
+	const std::vector<AddOp> ops {
+		{{'A', 0u}, 'a', std::nullopt, std::nullopt},
+		{{'A', 1u}, 'a', std::nullopt, ListType::ListID{'A', 0u}},
+		{{'A', 2u}, 'a', std::nullopt, ListType::ListID{'A', 1u}},
+		{{'B', 0u}, 'b', std::nullopt, std::nullopt},
+		{{'B', 1u}, 'b', std::nullopt, ListType::ListID{'B', 0u}},
+		{{'B', 2u}, 'b', std::nullopt, ListType::ListID{'B', 1u}},
+	};
+
+	randomAddPermutations(ops, "aaabbb");
+}
+
+void testConcurrent2(void) {
+	const std::vector<AddOp> ops {
+		{{'A', 0u}, 'a', std::nullopt, std::nullopt},
+		{{'C', 0u}, 'c', std::nullopt, std::nullopt},
+		{{'B', 0u}, 'b', std::nullopt, std::nullopt},
+		{{'D', 0u}, 'd', ListType::ListID{'A', 0u}, ListType::ListID{'C', 0u}},
+	};
+
+	randomAddPermutations(ops, "adbc");
+}
+
+void testMain1(void) {
+	ListType list;
+
+	static_assert('0' < '1');
+
+	const std::vector<AddOp> a0_ops {
+		{{'0', 0u}, 'a', std::nullopt, std::nullopt},
+		{{'0', 1u}, 'b', ListType::ListID{'0', 0u}, std::nullopt},
+		{{'0', 2u}, 'c', ListType::ListID{'0', 1u}, std::nullopt},
+		{{'0', 3u}, 'd', ListType::ListID{'0', 1u}, ListType::ListID{'0', 2u}},
+	};
+
+	const std::vector<AddOp> a1_ops {
+		// knows of a0 up to {a0, 1}
+		{{'1', 0u}, 'z', ListType::ListID{'0', 0u}, ListType::ListID{'0', 1u}},
+		{{'1', 1u}, 'y', ListType::ListID{'0', 1u}, std::nullopt},
+	};
+
+	{ // the ez, in order stuff
+		// a0 insert first char, 'a', since its the first, we dont have any parents
+		assert(list.add(a0_ops[0].id, a0_ops[0].value, a0_ops[0].parent_left, a0_ops[0].parent_right));
+		assert(list.getArray() == "a");
+
+		// a0 insert secound char, 'b' after 'a', no parents to right
+		assert(list.add(a0_ops[1].id, a0_ops[1].value, a0_ops[1].parent_left, a0_ops[1].parent_right));
+		assert(list.getArray() == "ab");
+
+		// a0 insert 'c' after 'b', no parents to right
+		assert(list.add(a0_ops[2].id, a0_ops[2].value, a0_ops[2].parent_left, a0_ops[2].parent_right));
+		assert(list.getArray() == "abc");
+
+		// a0 insert 'd' after 'b', 'c' parent right
+		assert(list.add(a0_ops[3].id, a0_ops[3].value, a0_ops[3].parent_left, a0_ops[3].parent_right));
+		assert(list.getArray() == "abdc");
+
+		// a1 insert 'z' after 'a', 'b' parent right
+		assert(list.add(a1_ops[0].id, a1_ops[0].value, a1_ops[0].parent_left, a1_ops[0].parent_right));
+		assert(list.getArray() == "azbdc");
+	}
+
+	std::cout << "done with ez\n";
+
+	{ // a1 was not uptodate only had 0,1 of a0
+		// a1 insert 'y' after 'b', no parent right
+		assert(list.add(a1_ops[1].id, a1_ops[1].value, a1_ops[1].parent_left, a1_ops[1].parent_right));
+		assert(list.getArray() == "azbdcy");
+	}
+
+	std::cout << "\ndoc size (with tombstones): " << list._list_ids.size() << "\n";
+	std::cout << "\ndoc size: " << list.getDocSize() << "\n";
+	std::cout << "doc text:\n";
+
+	const auto tmp_array = list.getArray();
+	std::cout << std::string_view(tmp_array.data(), tmp_array.size()) << "\n";
+}
+
+int main(void) {
+	std::cout << "testSingle1:\n";
+	testSingle1();
+	std::cout << std::string(40, '-') << "\n";
+
+	std::cout << "testConcurrent1:\n";
+	testConcurrent1();
+	std::cout << std::string(40, '-') << "\n";
+
+	std::cout << "testInterleave1:\n";
+	testInterleave1();
+	std::cout << std::string(40, '-') << "\n";
+
+	std::cout << "testInterleave2:\n";
+	testInterleave2();
+	std::cout << std::string(40, '-') << "\n";
+
+	std::cout << "testConcurrent2:\n";
+	testConcurrent2();
+	std::cout << std::string(40, '-') << "\n";
+
+	std::cout << "testMain1:\n";
+	testMain1();
+	std::cout << std::string(40, '-') << "\n";
+
+	return 0;
+}
+

version3/test2.cpp

@@ -0,0 +1,701 @@
+#include <green_crdt/v3/text_document.hpp>
+
+#include <numeric>
+#include <optional>
+#include <random>
+#include <iostream>
+#include <cassert>
+#include <variant>
+
+// single letter agent, for testing only
+using Agent = std::string;
+using Doc = GreenCRDT::V3::TextDocument<Agent>;
+using Op = Doc::Op;
+using ListType = Doc::ListType;
+
+// maybe switch it up?
+//using Rng = std::minstd_rand;
+//using Rng = std::mt19937;
+using Rng = std::ranlux24_base;
+
+// 10*7 -> 70 permutations , ggwp
+//               | 1add | 1del | 1rep | 2add | 2del | 2rep | random add | random del | random rep | random
+// empty doc     |      | 0    | 0    |      | 0    | 0    | x          | 0          | 0          |
+// before 1 char |      |      |      |      |      |      |            |            |            |
+// after 1 char  |      |      |      |      |      |      |            |            |            |
+// before 2 char |      |      |      |      |      |      |            |            |            |
+// in 2 char     |      |      |      |      |      |      |            |            |            |
+// after 2 char  |      |      |      |      |      |      |            |            |            |
+// random        |      |      |      |      |      |      |            |            |            |
+
+static const std::vector<char> random_chars {
+	'a', 'b', 'c', 'd', 'e',
+	'f', 'g', 'h', 'i', 'j',
+	'k', 'l', 'm', 'n', 'o',
+	'p', 'q', 'r', 's', 't',
+	'u', 'v', 'w', 'x', 'y',
+	'z',
+
+	'A', 'B', 'C', 'D', 'E',
+	'F', 'G', 'H', 'I', 'J',
+	'K', 'L', 'M', 'N', 'O',
+	'P', 'Q', 'R', 'S', 'T',
+	'U', 'V', 'W', 'X', 'Y',
+	'Z',
+};
+
+std::ostream& operator<<(std::ostream& out, const std::optional<ListType::ListID>& id) {
+	if (id.has_value()) {
+		out << id.value().id << "-" << id.value().seq;
+	} else {
+		out << "null";
+	}
+	return out;
+}
+
+std::ostream& operator<<(std::ostream& out, const Doc::OpAdd& op) {
+	out
+		<< "{ id:" << op.id.id
+		<< "-" << op.id.seq
+		<< ", v:" << op.value
+		<< ", l:" << op.parent_left
+		<< ", r:" << op.parent_right
+		<< " }"
+	;
+	return out;
+}
+
+// genX() changes doc, uses local agent
+
+Op genAdd(Rng& rng, Doc& doc) {
+	Doc::OpAdd op {
+		{doc.local_actor, 0u},
+		std::nullopt,
+		std::nullopt,
+		random_chars[rng()%random_chars.size()]
+	};
+
+	// TODO: move to list
+	// make sure actor index exists
+	if (!doc.state.findActor(doc.local_actor).has_value()) {
+		doc.state._actors.push_back(doc.local_actor);
+	}
+
+	// first id is 0
+	if (doc.state._last_seen_seq.count(doc.state.findActor(doc.local_actor).value())) {
+		op.id.seq = doc.state._last_seen_seq[doc.state.findActor(doc.local_actor).value()] + 1;
+	}
+
+	if (!doc.state.empty()) {
+		// gen parents
+		size_t li = rng()%(1+doc.state.size());
+		if (li != doc.state.size()) { // nullopt
+			op.parent_left = doc.state.getID(li);
+		}
+
+		//size_t r_range = 1+doc.state.list.size();
+		//if (li != doc.state.list.size()) {
+			//r_range -= li+1;
+		//}
+		//size_t ri = rng()%r_range;
+		//if (li != doc.state.list.size()) {
+			//ri += li+1;
+		//}
+		//if (ri != doc.state.list.size()) { // nullopt
+			//op.parent_right = doc.state.list[li].id;
+		//}
+
+		if (op.parent_left.has_value()) {
+			if (doc.state.size() != li + 1) { // left is not last
+				op.parent_right = doc.state.getID(li+1);
+			}
+		} else {
+			// left is before first, so right is first
+			op.parent_right = doc.state.getID(0);
+		}
+	} // else first char, both nullopt
+
+	//std::cout << "op: " << op << "\n";
+
+	{
+		bool r = doc.state.add(op.id, op.value, op.parent_left, op.parent_right);
+		if (!r) {
+			std::cout << "op: " << op << "\n";
+		}
+		assert(r);
+	}
+
+	return op;
+}
+
+Op genDel(Rng& rng, Doc& doc) {
+	if (doc.state.getDocSize() == 0) {
+		assert(false && "empty doc");
+		return {}; // empty
+	}
+
+	doc.state.verify();
+
+	Doc::OpDel op{};
+
+	// search for undelted entry
+	size_t idx = rng()%doc.state.size();
+	bool found = false;
+	for (size_t attempts = 0; attempts <= doc.state.size(); attempts++) {
+		//if (doc.state.list[idx].value.has_value()) {
+		if (doc.state.getValue(idx).has_value()) {
+			op.id = doc.state.getID(idx);
+			found = true;
+			break;
+		}
+		idx = (idx+1) % doc.state.size();
+	}
+
+	assert(found);
+
+	{
+		auto size_pre = doc.state.getDocSize();
+		bool r = doc.state.del(op.id);
+		assert(r);
+		assert(size_pre-1 == doc.state.getDocSize());
+		assert(doc.state.verify());
+	}
+
+	return op;
+}
+
+//genRep()
+//genAddContRange()
+//genDelContRange()
+//genRepContRange()
+
+//genRand()
+//genRandRanges()
+std::vector<Op> genRandAll(Rng& rng, Doc& doc) {
+	switch (rng() % 1) {
+		case 0:
+			return {genAdd(rng, doc)};
+	}
+
+	return {};
+}
+
+void testEmptyDocAdds(size_t seed) {
+	Rng rng(seed);
+
+	Doc doc; // empty
+	doc.local_actor = 'A';
+
+	std::string changed_text;
+	{
+		// for modifying
+		Doc doctmp = doc;
+
+		const size_t loop_count = (rng() % 55)+1;
+		for (size_t i = 0; i < loop_count; i++) {
+			genAdd(rng, doctmp);
+		}
+
+		changed_text = doctmp.getText();
+	}
+
+	assert(doc.getText() != changed_text);
+
+	std::cout << "changed_text: " << changed_text << "\n";
+
+	Doc otherdoc = doc;
+	assert(doc.getText().size() == doc.state.getDocSize());
+	const auto merge_ops = doc.merge(changed_text);
+	assert(doc.getText().size() == doc.state.getDocSize());
+
+	assert(doc.getText() == changed_text);
+
+	assert(otherdoc.apply(merge_ops));
+	assert(doc.getText() == otherdoc.getText());
+}
+
+void test1CharDocAdds(size_t seed) {
+	Rng rng(seed);
+
+	Doc doc;
+	doc.local_actor = 'A';
+
+	doc.addText(std::nullopt, std::nullopt, "0");
+
+	assert(doc.getText() == "0");
+
+	std::string changed_text;
+	{
+		// for modifying
+		Doc doctmp = doc;
+
+		const size_t loop_count = (rng() % 4)+1;
+		for (size_t i = 0; i < loop_count; i++) {
+			genAdd(rng, doctmp);
+		}
+
+		changed_text = doctmp.getText();
+	}
+
+	assert(doc.getText() != changed_text);
+
+	std::cout << "text: " << doc.getText() << "\n";
+	std::cout << "changed_text: " << changed_text << "\n";
+
+	Doc otherdoc = doc;
+	assert(doc.getText().size() == doc.state.getDocSize());
+	const auto merge_ops = doc.merge(changed_text);
+	assert(doc.getText().size() == doc.state.getDocSize());
+
+	std::cout << "text after merge: " << doc.getText() << "\n";
+
+	assert(doc.getText() == changed_text);
+
+	assert(otherdoc.apply(merge_ops));
+	assert(doc.getText() == otherdoc.getText());
+}
+
+void test1CharDocDels(size_t seed) {
+	Rng rng(seed);
+
+	Doc doc;
+	doc.local_actor = 'A';
+
+	assert(doc.getText().size() == doc.state.getDocSize());
+	doc.addText(std::nullopt, std::nullopt, "0123");
+	assert(doc.getText().size() == doc.state.getDocSize());
+
+	assert(doc.getText() == "0123");
+
+	std::string changed_text;
+	{
+		// for modifying
+		Doc doctmp = doc;
+
+		const size_t loop_count = (rng() % 4)+1;
+		std::cout << "going to delete: "  << loop_count << "\n";
+		for (size_t i = 0; i < loop_count; i++) {
+			genDel(rng, doctmp);
+		}
+
+		changed_text = doctmp.getText();
+		assert(doctmp.getText().size() == doctmp.state.getDocSize());
+
+		if (loop_count == doc.state.getDocSize()) {
+			assert(doctmp.state.getDocSize() == 0);
+			assert(changed_text.size() == 0);
+		}
+	}
+
+	assert(doc.getText() != changed_text);
+
+	std::cout << "text: " << doc.getText() << "\n";
+	std::cout << "changed_text: " << changed_text << "\n";
+
+	Doc otherdoc = doc;
+	assert(doc.getText().size() == doc.state.getDocSize());
+	const auto merge_ops = doc.merge(changed_text);
+	assert(doc.getText().size() == doc.state.getDocSize());
+
+	std::cout << "text after merge: " << doc.getText() << "\n";
+
+	assert(doc.getText() == changed_text);
+
+	assert(otherdoc.apply(merge_ops));
+	assert(doc.getText() == otherdoc.getText());
+}
+
+void test2CharDocAdds(size_t seed) {
+	Rng rng(seed);
+
+	Doc doc;
+	doc.local_actor = 'A';
+
+	assert(doc.getText().size() == doc.state.getDocSize());
+	doc.addText(std::nullopt, std::nullopt, "012345");
+	assert(doc.getText().size() == doc.state.getDocSize());
+
+	assert(doc.getText() == "012345");
+
+	std::string changed_text;
+	{
+		// for modifying
+		Doc doctmp = doc;
+
+		const size_t loop_count = (rng() % 6)+1;
+		for (size_t i = 0; i < loop_count; i++) {
+			genAdd(rng, doctmp);
+		}
+
+		changed_text = doctmp.getText();
+	}
+
+	assert(doc.getText() != changed_text);
+
+	std::cout << "text: " << doc.getText() << "\n";
+	std::cout << "changed_text: " << changed_text << "\n";
+
+	Doc otherdoc = doc;
+	assert(doc.getText().size() == doc.state.getDocSize());
+	const auto merge_ops = doc.merge(changed_text);
+	assert(doc.getText().size() == doc.state.getDocSize());
+
+	std::cout << "text after merge: " << doc.getText() << "\n";
+
+	assert(doc.getText() == changed_text);
+
+	assert(otherdoc.apply(merge_ops));
+	assert(doc.getText() == otherdoc.getText());
+}
+
+void testChange1(size_t seed) {
+	Rng rng(seed);
+
+	Doc doc;
+	doc.local_actor = 'A';
+
+	assert(doc.getText().size() == doc.state.getDocSize());
+	doc.addText(std::nullopt, std::nullopt, "012345");
+	assert(doc.getText().size() == doc.state.getDocSize());
+
+	assert(doc.getText() == "012345");
+
+	std::string changed_text;
+	{
+		// for modifying
+		Doc doctmp = doc;
+
+		{ // dels
+			const size_t loop_count = (rng() % 6)+1;
+			for (size_t i = 0; i < loop_count; i++) {
+				genDel(rng, doctmp);
+			}
+		}
+
+		{ // adds
+			const size_t loop_count = (rng() % 6)+1;
+			for (size_t i = 0; i < loop_count; i++) {
+				genAdd(rng, doctmp);
+			}
+		}
+
+		changed_text = doctmp.getText();
+	}
+
+	assert(doc.getText() != changed_text);
+
+	std::cout << "text: " << doc.getText() << "\n";
+	std::cout << "changed_text: " << changed_text << "\n";
+
+	Doc otherdoc = doc;
+	assert(doc.getText().size() == doc.state.getDocSize());
+	const auto merge_ops = doc.merge(changed_text);
+	assert(doc.getText().size() == doc.state.getDocSize());
+
+	std::cout << "text after merge: " << doc.getText() << "\n";
+
+	assert(doc.getText() == changed_text);
+
+	assert(otherdoc.apply(merge_ops));
+	assert(doc.getText() == otherdoc.getText());
+}
+
+void testBugSame(void) {
+	Doc doc;
+	doc.local_actor = 'A';
+
+	std::string_view new_text1{"a"};
+	doc.merge(new_text1);
+	assert(doc.getText() == new_text1);
+
+	std::string_view new_text2{"aa"};
+	doc.merge(new_text2);
+	assert(doc.getText() == new_text2);
+}
+
+void testBugDoubleDel(void) {
+	Doc doc;
+	doc.local_actor = 'A';
+
+	{
+		std::string_view new_text{"a"};
+		const auto ops = doc.merge(new_text);
+		assert(doc.getText() == new_text);
+		assert(ops.size() == 1);
+	}
+
+	{
+		std::string_view new_text{""};
+		const auto ops = doc.merge(new_text);
+		assert(doc.getText() == new_text);
+		assert(ops.size() == 1);
+		assert(std::holds_alternative<Doc::OpDel>(ops.front()));
+		assert(std::get<Doc::OpDel>(ops.front()).id.seq == 0);
+	}
+
+	{
+		std::string_view new_text{""};
+		const auto ops = doc.merge(new_text);
+		assert(doc.getText() == new_text);
+		assert(ops.size() == 0);
+	}
+}
+
+void testBugSameDel(void) {
+	Doc doc;
+	doc.local_actor = 'A';
+
+	{
+		std::string_view new_text{"a"};
+		const auto ops = doc.merge(new_text);
+		assert(doc.getText() == new_text);
+		assert(ops.size() == 1);
+	}
+
+	{
+		std::string_view new_text{"aa"};
+		const auto ops = doc.merge(new_text);
+		assert(doc.getText() == new_text);
+		assert(ops.size() == 1);
+	}
+
+	{
+		std::string_view new_text{"a"};
+		const auto ops = doc.merge(new_text);
+		assert(doc.getText() == new_text);
+		assert(ops.size() == 1);
+	}
+}
+
+void testBugSameDel2(void) {
+	Doc doc;
+	doc.local_actor = 'A';
+
+	{
+		std::string_view new_text{"a"};
+		const auto ops = doc.merge(new_text);
+		assert(doc.getText() == new_text);
+		assert(ops.size() == 1);
+	}
+
+	{
+		std::string_view new_text{"aa"};
+		const auto ops = doc.merge(new_text);
+		assert(doc.getText() == new_text);
+		assert(ops.size() == 1);
+	}
+
+	{
+		std::string_view new_text{"aaa"};
+		const auto ops = doc.merge(new_text);
+		assert(doc.getText() == new_text);
+		assert(ops.size() == 1);
+	}
+
+	{
+		std::string_view new_text{"aa"};
+		const auto ops = doc.merge(new_text);
+		assert(doc.getText() == new_text);
+		assert(ops.size() == 1);
+	}
+
+	{
+		std::string_view new_text{"a"};
+		const auto ops = doc.merge(new_text);
+		assert(doc.getText() == new_text);
+		assert(ops.size() == 1);
+	}
+}
+
+void testMulti1(void) {
+	Doc docA;
+	docA.local_actor = 'A';
+
+	Doc docB;
+	docB.local_actor = 'B';
+
+	// state A
+	{
+		std::string_view new_text{"iiiiiii"};
+		const auto ops = docA.merge(new_text);
+		assert(docA.getText() == new_text);
+
+		assert(docB.apply(ops));
+
+		assert(docB.getText() == new_text);
+		assert(docB.state.getDocSize() == docA.state.getDocSize());
+		assert(docB.state.size() == docA.state.size());
+	}
+
+	// now B inserts b
+	{
+		std::string_view new_text{"iiibiiii"};
+		const auto ops = docB.merge(new_text);
+		assert(docB.getText() == new_text);
+		assert(ops.size() == 1); // 1 new inserted char, nothing to delete
+
+		assert(docA.apply(ops));
+
+		assert(docA.getText() == new_text);
+	}
+}
+
+void testPaste1(void) {
+	Doc docA;
+	docA.local_actor = 'A';
+
+	{
+		std::string_view new_text{"iiiiiii"};
+		const auto ops = docA.merge(new_text);
+		assert(ops.size() == 7);
+		assert(docA.getText() == new_text);
+	}
+
+	{
+		std::string_view new_text{"iiiiiii\n"};
+		const auto ops = docA.merge(new_text);
+		assert(ops.size() == 1);
+		assert(docA.getText() == new_text);
+	}
+
+	{
+		std::string_view new_text{"iiiiiii\niiiiiii"};
+		const auto ops = docA.merge(new_text);
+		assert(ops.size() == 7);
+		assert(docA.getText() == new_text);
+	}
+}
+
+void testPaste2(void) {
+	Doc docA;
+	docA.local_actor = 'A';
+
+	{
+		std::string_view new_text{"aiiiiib"};
+		const auto ops = docA.merge(new_text);
+		assert(ops.size() == 7);
+		assert(docA.getText() == new_text);
+	}
+
+	{
+		std::string_view new_text{"aiiiiib\n"};
+		const auto ops = docA.merge(new_text);
+		assert(ops.size() == 1);
+		assert(docA.getText() == new_text);
+	}
+
+	{
+		std::string_view new_text{"aiiiiib\naiiiiib"};
+		const auto ops = docA.merge(new_text);
+		assert(ops.size() == 7);
+		assert(docA.getText() == new_text);
+	}
+}
+
+int main(void) {
+	const size_t loops = 1'000;
+	{
+		std::cout << "testEmptyDocAdds:\n";
+		for (size_t i = 0; i < loops; i++) {
+			std::cout << "i " << i << "\n";
+			testEmptyDocAdds(1337+i);
+			std::cout << std::string(40, '-') << "\n";
+		}
+	}
+
+	std::cout << std::string(40, '=') << "\n";
+
+	{
+		std::cout << "test1CharDocAdds:\n";
+		for (size_t i = 0; i < loops; i++) {
+			std::cout << "i " << i << "\n";
+			test1CharDocAdds(1337+i);
+			std::cout << std::string(40, '-') << "\n";
+		}
+	}
+
+	std::cout << std::string(40, '=') << "\n";
+
+	{
+		std::cout << "test1CharDocDels:\n";
+		for (size_t i = 0; i < loops; i++) {
+			std::cout << "i " << i << "\n";
+			test1CharDocDels(1337+i);
+			std::cout << std::string(40, '-') << "\n";
+		}
+	}
+
+	std::cout << std::string(40, '=') << "\n";
+
+	{
+		std::cout << "test2CharDocAdds:\n";
+		for (size_t i = 0; i < loops; i++) {
+			std::cout << "i " << i << "\n";
+			test2CharDocAdds(1337+i);
+			std::cout << std::string(40, '-') << "\n";
+		}
+	}
+
+	std::cout << std::string(40, '=') << "\n";
+
+	{
+		std::cout << "testChange1:\n";
+		for (size_t i = 0; i < loops; i++) {
+			std::cout << "i " << i << "\n";
+			testChange1(1337+i);
+			std::cout << std::string(40, '-') << "\n";
+		}
+	}
+
+	std::cout << std::string(40, '=') << "\n";
+
+	{
+		std::cout << "testBugSame:\n";
+		testBugSame();
+	}
+
+	std::cout << std::string(40, '=') << "\n";
+
+	{
+		std::cout << "testBugDoubleDel:\n";
+		testBugDoubleDel();
+	}
+
+	std::cout << std::string(40, '=') << "\n";
+
+	{
+		std::cout << "testBugSameDel:\n";
+		testBugSameDel();
+	}
+
+	std::cout << std::string(40, '=') << "\n";
+
+	{
+		std::cout << "testBugSameDel2:\n";
+		testBugSameDel2();
+	}
+
+	std::cout << std::string(40, '=') << "\n";
+
+	{
+		std::cout << "testMulti1:\n";
+		testMulti1();
+	}
+
+	std::cout << std::string(40, '=') << "\n";
+
+	{
+		std::cout << "testPaste1:\n";
+		testPaste1();
+	}
+
+	std::cout << std::string(40, '=') << "\n";
+
+	{
+		std::cout << "testPaste2:\n";
+		testPaste2();
+	}
+
+	return 0;
+}
+