104 lines
2.2 KiB
C++
104 lines
2.2 KiB
C++
#include <algorithm>
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#include <array>
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#include <cassert>
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#include <iostream>
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#include <list>
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#include <map>
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#include <regex>
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#include <set>
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#include <string>
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#include <tuple>
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struct Matcher
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{
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void add_rule(std::string const& s)
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{
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std::size_t len = 0;
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unsigned long id = std::stoul(s, &len);
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assert(s[len] == ':');
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++len;
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while (s[len] == ' ') {
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++len;
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}
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if (rules_.size() <= id) {
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rules_.resize(id + 1);
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}
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rules_[id] = s.substr(len);
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}
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void calculate_regex() { re_.assign("^" + expand_rule(0) + "$"); }
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bool does_match(std::string const& s) const { return std::regex_match(s, re_); }
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private:
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std::string expand_rule(std::size_t id)
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{
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std::string re;
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std::string const& rule = rules_[id];
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std::size_t pos = 0;
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bool needs_brackets = false;
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while (pos < rule.size()) {
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if (rule[pos] == ' ') {
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++pos;
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}
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else if (rule[pos] == '|') {
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re += "|";
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needs_brackets = true;
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++pos;
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}
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else if (rule[pos] == '"') {
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++pos;
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while (pos < rule.size() && rule[pos] != '"') {
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re += rule[pos];
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++pos;
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}
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assert(pos < rule.size());
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assert(rule[pos] == '"');
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++pos;
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}
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else if (std::isdigit(rule[pos])) {
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std::size_t len = 0;
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std::size_t subid = std::stoul(rule.substr(pos), &len);
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pos += len;
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re += expand_rule(subid);
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}
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else {
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assert(false);
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}
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}
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if (needs_brackets) {
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re = "(" + re + ")";
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}
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std::cout << "Rule " << id << " expands to: " << re << "\n";
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return re;
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}
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std::vector<std::string> rules_;
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std::regex re_;
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};
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int main(void)
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{
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std::string line;
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Matcher matcher;
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bool adding_rules = true;
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unsigned matches = 0;
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while (std::getline(std::cin, line)) {
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if (line.empty()) {
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adding_rules = false;
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matcher.calculate_regex();
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}
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else if (adding_rules) {
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matcher.add_rule(line);
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}
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else {
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bool m = matcher.does_match(line);
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std::cout << line << ": does " << (m ? "" : "not ") << "match\n";
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matches += m;
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}
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}
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std::cout << "Total number of matches: " << matches << "\n";
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return 0;
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} |