mirror of
https://github.com/Green-Sky/crdt_tests.git
synced 2024-11-14 18:13:01 +01:00
284 lines
7.3 KiB
C++
284 lines
7.3 KiB
C++
#pragma once
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#include "./list.hpp"
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#include <optional>
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#include <variant>
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#include <vector>
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#include <iostream> // debug
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namespace GreenCRDT {
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template<typename AgentType>
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struct TextDocument {
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// TODO: determine if char is the best
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using ListType = List<char, AgentType>;
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using Op = std::variant<typename ListType::OpAdd, typename ListType::OpDel>;
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struct Cursor {
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AgentType who;
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typename ListType::ListID pos;
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};
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AgentType local_agent;
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ListType state;
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[[nodiscard]] std::string getText(void) const {
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std::string text;
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for (const auto& it : state.list) {
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if (it.value.has_value()) {
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text += it.value.value();
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}
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}
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return text;
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}
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bool apply(const Op& op) {
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if(std::holds_alternative<typename ListType::OpAdd>(op)) {
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const auto& add_op = std::get<typename ListType::OpAdd>(op);
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//std::cout << "a:" << add_op.id.id << " s:" << add_op.id.seq << " v:" << add_op.value << "\n";
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return state.add(add_op.id, add_op.value, add_op.parent_left, add_op.parent_right);
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} else if (std::holds_alternative<typename ListType::OpDel>(op)) {
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const auto& del_op = std::get<typename ListType::OpDel>(op);
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return state.del(del_op.id);
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} else {
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assert(false);
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}
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}
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bool apply(const std::vector<Op>& ops) {
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for (const auto& op : ops) {
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if (!apply(op)) {
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// this is not ideal, since we might have applyed some, and dont report which/howmany
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return false;
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}
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}
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return true;
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}
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static std::vector<Op> text2adds(
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const AgentType& agent, uint64_t seq, // seq is the first seq
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std::optional<typename ListType::ListID> parent_left,
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std::optional<typename ListType::ListID> parent_right,
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std::string_view text
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) {
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std::vector<Op> ops;
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for (size_t i = 0; i < text.size(); i++) {
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typename ListType::ListID new_id {agent, seq++};
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ops.emplace_back(typename ListType::OpAdd{
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new_id,
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parent_left,
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parent_right,
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text[i]
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});
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parent_left = new_id;
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}
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return ops;
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}
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// adds in tast with specified parents
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// returns generated ops
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std::vector<Op> addText(
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std::optional<typename ListType::ListID> parent_left,
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std::optional<typename ListType::ListID> parent_right,
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std::string_view text
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) {
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// TODO: look up typesystem and fix (move? decltype?)
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std::vector<Op> ops = text2adds(
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local_agent, state.last_seen_seq.count(local_agent) ? state.last_seen_seq[local_agent]+1u : 0u,
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parent_left,
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parent_right,
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text
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);
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// TODO: make this better
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// and apply
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for (const auto& op : ops) {
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if(std::holds_alternative<typename ListType::OpAdd>(op)) {
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const auto& add_op = std::get<typename ListType::OpAdd>(op);
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//std::cout << "a:" << add_op.id.id << " s:" << add_op.id.seq << " v:" << add_op.value << "\n";
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bool r = state.add(add_op.id, add_op.value, add_op.parent_left, add_op.parent_right);
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assert(r);
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} else if (std::holds_alternative<typename ListType::OpDel>(op)) {
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const auto& del_op = std::get<typename ListType::OpDel>(op);
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state.del(del_op.id);
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} else {
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assert(false);
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}
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}
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return ops; // TODO: move?
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}
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// deletes everything in range [first, last)
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// returns generated ops
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std::vector<Op> delRange(
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std::optional<typename ListType::ListID> left,
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std::optional<typename ListType::ListID> right
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) {
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size_t first_idx = 0;
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if (left.has_value()) {
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auto res = state.findIdx(left.value());
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if (!res.has_value()) {
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assert(false && "cant find left");
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return {};
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}
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first_idx = res.value();
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}
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size_t last_idx = state.list.size();
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if (right.has_value()) {
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auto res = state.findIdx(right.value());
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if (!res.has_value()) {
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assert(false && "cant find right");
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return {};
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}
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last_idx = res.value();
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}
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std::vector<Op> ops;
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for (size_t i = first_idx; i < last_idx; i++) {
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ops.emplace_back(typename ListType::OpDel{
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state.list[i].id
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});
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// TODO: do delets get a seq?????
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state.del(state.list[i].id);
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}
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return ops;
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}
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// generates ops from the difference
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// note: rn it only creates 1 diff patch
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std::vector<Op> merge(std::string_view text) {
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// cases:
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// - [ ] text is empty
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// - [x] doc is empty (deep)
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// - [ ] doc is empty (shallow) // interesting?
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//
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// - [x] no changes -> change_start will go through to end
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//
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// not at start or end:
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// - [ ] single char added -> doc.start > doc.end && text.start == text.end -> emit add
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// - [ ] single char deleted -> doc.start == doc.end && text.start > text.end -> emit del
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// - [ ] single char replaced -> doc.start == doc.end && text.start == text.end -> emit del, emit add
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//
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// - [ ] 2 chars added(together) -> doc.start > doc.end && text.start < text.end -> emit 2add
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// - [ ] 2 chars deleted(together) -> doc.start < doc.end && text.start > text.end -> emit 2del
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// - [ ] 2 chars replaced(together) -> doc.start == doc.end && text.start == text.end -> emit 2del, 2add
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if (text.empty()) {
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if (state.list.empty()) {
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// no op
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return {};
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} else {
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// delete all
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return delRange(std::nullopt, std::nullopt);
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}
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}
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// text not empty
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if (state.list.empty()) {
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return addText(
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std::nullopt,
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std::nullopt,
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text
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);
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}
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// neither empty
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// find start and end of changes
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// start
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size_t list_start = 0;
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size_t text_start = 0;
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bool differ = false;
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for (; list_start < state.list.size() && text_start < text.size();) {
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// jump over tombstones
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if (!state.list[list_start].value.has_value()) {
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list_start++;
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continue;
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}
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if (state.list[list_start].value.value() != text[text_start]) {
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differ = true;
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break;
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}
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list_start++;
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text_start++;
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}
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// doc and text dont differ
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if (!differ && list_start == state.list.size() && text_start == text.size()) {
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return {};
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}
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std::cout << "list.size: " << state.list.size() << "(" << getText().size() << ")" << " text.size: " << text.size() << "\n";
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std::cout << "list_start: " << list_start << " text_start: " << text_start << "\n";
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// +1 so i can have unsigned
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size_t list_end = state.list.size();
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size_t text_end = text.size();
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for (; list_end > 0 && text_end > 0 && list_end >= list_start && text_end >= text_start;) {
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// jump over tombstones
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if (!state.list[list_end-1].value.has_value()) {
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list_end--;
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continue;
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}
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if (state.list[list_end-1].value.value() != text[text_end-1]) {
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break;
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}
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list_end--;
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text_end--;
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}
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std::cout << "list_end: " << list_end << " text_end: " << text_end << "\n";
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std::vector<Op> ops;
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// 1. clear range (del all list_start - list_end)
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if (list_start <= list_end && list_start < state.list.size()) {
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ops = delRange(
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state.list[list_start].id,
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list_end < state.list.size() ? std::make_optional(state.list[list_end].id) : std::nullopt
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);
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std::cout << "deleted: " << ops.size() << "\n";
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}
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std::cout << "text between: " << getText() << "\n";
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// 2. add range (add all text_start - text_end)
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if (text_start < text_end) {
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auto tmp_add_ops = addText(
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list_start == 0 ? std::nullopt : std::make_optional(state.list[list_start-1].id),
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list_start == state.list.size() ? std::nullopt :std::make_optional(state.list.at(list_start).id),
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text.substr(text_start, text_end-text_start)
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);
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std::cout << "added: " << tmp_add_ops.size() << "\n";
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ops.insert(ops.end(), tmp_add_ops.begin(), tmp_add_ops.end());
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}
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//assert(false && "implement me");
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return ops;
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}
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};
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} // GreenCRDT
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