Ugly hacky code-duplication finder.

test.cpp

#include <iostream>
#include <fstream>
#include <map>
#include <set>
#include <vector>
#include <algorithm>

struct line {
	std::string file;
	size_t line_number;
	std::string text;
	line(std::string f, size_t l, std::string t) : file(f), line_number(l), text(t) {}
};

int main(int argc, char * * argv) {

	size_t min_match_length = 30;

	std::map<std::string, std::vector<size_t>> m;
	std::vector<line> v;

	for (int i = 1; i < argc; ++i) {
		std::string fn = argv[i];
		std::ifstream f{fn};
		std::string s;
		size_t l = 0;
		while (std::getline(f, s)) {
			++l;
			s.erase(std::remove_if(s.begin(), s.end(), [](char c) { return std::isspace(c); }), s.end());
			if (!s.empty()) v.emplace_back(fn, l, s);
		}
	}

	for (size_t i = 0; i < v.size(); ++i) {
		auto const & s = v[i].text;
		auto & o = m[s];
		bool found_match = false;
		for (size_t j : o) {
			size_t m = s.size();
			size_t n = 1;
			while (v[i+n].text == v[j+n].text) {
				m += v[i+n].text.size();
				++n;
			}
			if (m >= min_match_length) {
				found_match = true;
				std::cout << v[i].file << ":" << v[i].line_number << ": Duplicate of ... " << std::endl;
				std::cout << v[j].file << ":" << v[j].line_number << ": ... this." << std::endl;
				i += n;
				break;
			}
		}
		if (!found_match) o.push_back(i);
	}
}
/*
Some duplicated shit to test with:
	for (size_t i = 0; i < v.size(); ++i) {
		auto const & s = v[i].text;
		auto & o = m[s];
		bool found_match = false;
		for (size_t j : o) {
			size_t m = s.size();
			size_t n = 1;
			while (v[i+n].text == v[j+n].text) {
				m += v[i+n].text.size();
				++n;
			}
for (size_t i = 0; i < v.size(); ++i) {
	auto const & s = v[i].text;
	auto & o = m[s];
	bool found_match = false;
	for (size_t j : o) {
*/