diff --git a/extensions/removerepeat.cpp b/extensions/removerepeat.cpp
deleted file mode 100644
index 61d2ca1..0000000
--- a/extensions/removerepeat.cpp
+++ /dev/null
@@ -1,109 +0,0 @@
-#include "extension.h"
-
-void RemoveRepeatedSentences(std::wstring& sentence, uint64_t textNumber)
-{
-	static std::deque<Synchronized<std::vector<std::wstring>>> cache;
-	static std::mutex m;
-	m.lock();
-	if (textNumber + 1 > cache.size()) cache.resize(textNumber + 1);
-	auto prevSentences = cache.at(textNumber).Acquire();
-	m.unlock();
-	auto& inserted = prevSentences->emplace_back(sentence);
-	auto firstLocation = std::find(prevSentences->begin(), prevSentences->end(), sentence);
-	if (&*firstLocation != &inserted)
-	{
-		prevSentences->erase(firstLocation);
-		sentence.clear();
-	}
-	if (prevSentences->size() > 50) prevSentences->erase(prevSentences->begin());
-}
-
-void RemoveRepeatedChars(std::wstring& sentence)
-{
-	std::vector<int> repeatNumbers(sentence.size() + 1, 0);
-	int repeatNumber = 1;
-	wchar_t prevChar = L'\0';
-	for (auto nextChar : sentence)
-	{
-		if (nextChar == prevChar)
-		{
-			repeatNumber += 1;
-		}
-		else
-		{
-			prevChar = nextChar;
-			repeatNumbers.at(repeatNumber) += 1;
-			repeatNumber = 1;
-		}
-	}
-	if ((repeatNumber = std::distance(repeatNumbers.begin(), std::max_element(repeatNumbers.begin(), repeatNumbers.end()))) == 1) return;
-
-	std::wstring newSentence;
-	for (int i = 0; i < sentence.size();)
-	{
-		newSentence.push_back(sentence.at(i));
-		for (int j = i; j <= sentence.size(); ++j)
-		{
-			if (j == sentence.size() || sentence.at(i) != sentence.at(j))
-			{
-				i += (j - i) % repeatNumber == 0 ? repeatNumber : 1;
-				break;
-			}
-		}
-	}
-	sentence = newSentence;
-}
-
-void RemoveCyclicRepeats(std::wstring& sentence)
-{
-	if (sentence.size() > 15000) return; // this algorithm is O(N^3) so if N > 15000 it's extremely slow
-	auto data = std::make_unique<wchar_t[]>(sentence.size() + 1);
-	wcscpy_s(data.get(), sentence.size() + 1, sentence.c_str());
-	wchar_t* dataEnd = data.get() + sentence.size();
-	int skip = 0, count = 0;
-	for (wchar_t* end = dataEnd; end - data.get() > skip; --end)
-	{
-		std::swap(*end, *dataEnd);
-		int junkLength = end - data.get() - skip;
-		auto junkFound = wcsstr(sentence.c_str() + skip + junkLength, data.get() + skip);
-		std::swap(*end, *dataEnd);
-		if (junkFound)
-		{
-			if (count && junkLength < min(skip / count, 4)) break;
-			skip += junkLength;
-			count += 1;
-			end = dataEnd;
-		}
-	}
-	if (count && skip / count >= 3) sentence = data.get() + skip;
-}
-
-bool ProcessSentence(std::wstring& sentence, SentenceInfo sentenceInfo)
-{
-	if (sentenceInfo["text number"] == 0) return false;
-	RemoveRepeatedSentences(sentence, sentenceInfo["text number"]);
-	RemoveRepeatedChars(sentence);
-	RemoveCyclicRepeats(sentence);
-	return true;
-}
-
-TEST(
-	{
-		std::wstring repeatedChars = L"aaaaaaaaaaaabbbbbbcccdddaabbbcccddd";
-		RemoveRepeatedChars(repeatedChars);
-		assert(repeatedChars.find(L"aaaabbcd") == 0);
-
-		std::wstring cyclicRepeats = L"_abcde_abcdef_abcdefg_abcdefg_abcdefg_abcdefg_abcdefg";
-		std::wstring buildupRepeats = L"__a_ab_abc_abcd_abcde_abcdef_abcdefg";
-		RemoveCyclicRepeats(cyclicRepeats);
-		RemoveCyclicRepeats(buildupRepeats);
-		assert(cyclicRepeats == L"_abcdefg");
-		assert(buildupRepeats == L"_abcdefg");
-
-		std::wstring empty = L"", one = L" ", normal = L"This is a normal sentence. はい";
-		ProcessSentence(empty, { SentenceInfo::DUMMY });
-		ProcessSentence(one, { SentenceInfo::DUMMY });
-		ProcessSentence(normal, { SentenceInfo::DUMMY });
-		assert(empty == L"" && one == L" " && normal == L"This is a normal sentence. はい");
-	}
-);