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#include <sdsl/suffix_arrays.hpp>
#include <string>
#include <iostream>
#include <algorithm>
#include <iomanip>
using namespace sdsl;
using namespace std;
int main(int argc, char** argv)
{
if (argc < 2) {
cout << "Usage " << argv[0] << " text_file [max_locations] [post_context] [pre_context]" << endl;
cout << " This program constructs a very compact FM-index" << endl;
cout << " which supports count, locate, and extract queries." << endl;
cout << " text_file Original text file." << endl;
cout << " max_locations Maximal number of location to report." <<endl;
cout << " post_context Maximal length of the reported post-context." << endl;
cout << " pre_context Maximal length of the pre-context." << endl;
return 1;
}
size_t max_locations = 5;
size_t post_context = 10;
size_t pre_context = 10;
if (argc >= 3) {
max_locations = atoi(argv[2]);
}
if (argc >= 4) {
post_context = atoi(argv[3]);
}
if (argc >= 5) {
pre_context = atoi(argv[4]);
}
string index_suffix = ".fm9";
string index_file = string(argv[1])+index_suffix;
csa_wt<wt_huff<rrr_vector<127> >, 512, 1024> fm_index;
if (!load_from_file(fm_index, index_file)) {
ifstream in(argv[1]);
if (!in) {
cout << "ERROR: File " << argv[1] << " does not exist. Exit." << endl;
return 1;
}
cout << "No index "<<index_file<< " located. Building index now." << endl;
construct(fm_index, argv[1], 1); // generate index
store_to_file(fm_index, index_file); // save it
}
cout << "Index construction complete, index requires " << size_in_mega_bytes(fm_index) << " MiB." << endl;
cout << "Input search terms and press Ctrl-D to exit." << endl;
string prompt = "\e[0;32m>\e[0m ";
cout << prompt;
string query;
while (getline(cin, query)) {
size_t m = query.size();
size_t occs = sdsl::count(fm_index, query.begin(), query.end());
cout << "# of occurrences: " << occs << endl;
if (occs > 0) {
cout << "Location and context of first occurrences: " << endl;
auto locations = locate(fm_index, query.begin(), query.begin()+m);
sort(locations.begin(), locations.end());
for (size_t i = 0, pre_extract = pre_context, post_extract = post_context; i < min(occs, max_locations); ++i) {
cout << setw(8) << locations[i] << ": ";
if (pre_extract > locations[i]) {
pre_extract = locations[i];
}
if (locations[i]+m+ post_extract > fm_index.size()) {
post_extract = fm_index.size()-locations[i]-m;
}
auto s = extract(fm_index, locations[i]-pre_extract, locations[i]+m+ post_extract-1);
string pre = s.substr(0, pre_extract);
s = s.substr(pre_extract);
if (pre.find_last_of('\n') != string::npos) {
pre = pre.substr(pre.find_last_of('\n')+1);
}
cout << pre;
cout << "\e[1;31m";
cout << s.substr(0, m);
cout << "\e[0m";
string context = s.substr(m);
cout << context.substr(0, context.find_first_of('\n')) << endl;
}
}
cout << prompt;
}
cout << endl;
}
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