CounterDB

A Solution to durably store your counts. For example number of likes/dislikes on a post.

Its time complexity is O(1).

Single header only C++ file for storing and retrieving numbers.

It does this without increasing the file size, as its not append only DB. Which also means it can be slower on simultaneous writes to an index. Well if your task is just to store likes/dislikes counts, than it must not be much of a problem. As reads are done more than writes for such cases.

Usage example:

#include "counterDB/counterDB.hpp"

using namespace counterDB;
    
int main(int argc, const char** argv) {
    //create DB file : and maximum number of counter supported
    auto db = new CounterDB("./db/test1.db",10);

    //To check how many index have been issued so far.
    auto c = db->maxIndexIssued();
    unsigned long long t = 1;
    if(c==0){
        t = db->issueAnIndex();
    }
    
    db->increment(t);

    std::cout << "Count: " << db->read(t)<< std::endl;

    //Don't call it frequently. 
    //If you want greater durability, but it should be DO called. 
    //Though OS does sync it automatically.
    db->sync();

    delete db;
    return 0;
}

Notes:

1. To get maximum speed: Use a cache layer and pass bigger increments in one go using unsigned long long increment(unsigned long long index, unsigned long long increment=1).
2. An index can count upto maximum value of unsigned long long. So if you wanted higher counts than that, than you must use more than one index and sum them later using some custom logic.