int main()
{
std::vector<int> v = {1,2,3,4,5,6,7,8,9,10};
std::vector<int> v2 = functional_map(square, v);
for (int y : v2)
{
std::cout << y << " ";
}
}
void get_top(map<unsigned int,Metadata> &metadatas,vector<string> &arguments)
{
//This function takes two arguments. The first is the n-gram number, and the second is the number of results to display.
if(arguments.size() != 2)
{
cerr<<"search_inverted_index: Please give two arguments, where the first is the number of words in the n-gram and the second is the number of results to display."<<endl;
exit(-1);
}
unsigned int ngramsize = atoi(arguments[0].c_str());
if(!ngramsize)
{
cerr<<"search_inverted_index: Please give a valid non-zero number for the n-gram size as the first argument."<<endl;
exit(-1);
}
unsigned int num_to_display = atoi(arguments[1].c_str());
if(!num_to_display)
{
cerr<<"search_inverted_index: Please give a valid number for the n of n-gram that you want to search for as the second argument." <<endl;
exit(-1);
}
auto relevant_metadata_itr = metadatas.find(ngramsize);
if(relevant_metadata_itr == metadatas.end())
{
cerr<<"search_inverted_index: No metadata for "<<ngramsize<<"-grams found"<<endl;
exit(-1);
}
Metadata &relevant_metadata = relevant_metadata_itr->second;
vector<unsigned int> what_were_looking_for;
for(size_t i= 0; i< ngramsize; i++)
what_were_looking_for.push_back(i);
function<string(unsigned int)> unsigned_to_string = [](unsigned int in) -> string { return to_string(in);};
string index_specification = join(functional_map(what_were_looking_for,unsigned_to_string),"_");
string frequency_index_filename = relevant_metadata.output_folder_name + "/by_" + index_specification + "/0.out";
string inverted_frequency_index_filename = relevant_metadata.output_folder_name + "/inverted_by_" + index_specification;
if(find(relevant_metadata.inverted_indices.begin(), relevant_metadata.inverted_indices.end(),what_were_looking_for) == relevant_metadata.inverted_indices.end())
{
cerr<<"get_top: Did not find inverted index for the specified n"<<endl;
exit(-1);
}
ifstream inverted_frequency_index_file(inverted_frequency_index_filename.c_str());
if(!inverted_frequency_index_file)
{
cerr<<"get_top:"<<"Unable to open index file "<<inverted_frequency_index_filename<<endl;
exit(-1);
}
int frequency_index_fd = open(frequency_index_filename.c_str(),O_RDONLY);
if(frequency_index_fd < 0)
{
cerr<<"get_top: Could not open file"<<frequency_index_filename<<endl;
exit(-1);
}
off_t frequency_index_file_size = lseek(frequency_index_fd, 0 , SEEK_END);
void* mmaped_frequency_index = mmap(NULL,frequency_index_file_size,PROT_READ,MAP_SHARED,frequency_index_fd,0);
if(mmaped_frequency_index == (void*) -1)
{
cerr<<"get_top: Could not mmap file"<<frequency_index_filename<<endl;
exit(-1);
}
cerr<<"N-gram\tFrequency"<<endl;
string currentline;
//TODO: Possible write it out if we reach EOF too soon.
for(size_t i = 0; i< num_to_display && getline(inverted_frequency_index_file,currentline);i++)
{
const char* to_work_with = currentline.c_str();
char* endptr;
long long frequency = strtoll(to_work_with,&endptr, 16);
to_work_with = endptr;
to_work_with++;//Get rid of the "space" character in between.
off_t address = strtoll(to_work_with, &endptr, 16);
auto this_ngram = getNGramAtAddress(address,mmaped_frequency_index,frequency_index_file_size);
cout<<join(this_ngram.first,"\t")<<"\t"<<this_ngram.second<<endl;
if(frequency != this_ngram.second)
{
cerr<<"get_top: Frequencies in inverted index by frequency do not match frequency of n-grams in the indexes by n-gram, probably one of the two indexes is out of date, exiting.."<<endl;
munmap(mmaped_frequency_index,frequency_index_file_size);
close(frequency_index_fd);
}
}
munmap(mmaped_frequency_index,frequency_index_file_size);
close(frequency_index_fd);
}
