gistfile1.cc

/*
 * Rewritten from https://github.com/scanmem/scanmem/blob/d77b1713e548f6e26e62a3e146f852813bbee6d9/targetmem.h
 */

#include <iostream>
#include <vector>
#include <cstring>
#include <chrono>


using namespace std;
using namespace std::chrono;



/* Single match struct */
#pragma pack(push, 1)
struct byte_with_flags
{
    uint8_t byte;       // Remote process byte
    uint16_t flags;     // Flag
};
#pragma pack(pop)


class swath_t
{
public:
    uintptr_t base_address;             // Base remote address
    vector<byte_with_flags> data;       //

    explicit swath_t(uintptr_t base_address)
            : base_address(base_address) {
//        data.reserve(2096000000uL);
    }

    uintptr_t
    remote_get(size_t n) {
        return base_address + n;
    }

    uintptr_t
    remote_back() {
        return remote_get(data.size() - 1);
    }
};

vector<swath_t> swaths;

void add_element(const uintptr_t& remote_address) {
    // timestamp = high_resolution_clock::now();
    if (swaths.empty()) {
        swaths.emplace_back(100);
        cout<<"a"<<endl;
    }
    size_t remote_delta = remote_address - swaths.back().remote_back();
    size_t local_delta = remote_delta * sizeof(byte_with_flags);
    // seconds_total += duration_cast<duration<double>>(high_resolution_clock::now() - timestamp).count();


    if (local_delta >= sizeof(swath_t) + swaths.back().data.capacity() + sizeof(byte_with_flags)) {
        /// It is more memory-efficient to start a new swath
        swaths.emplace_back(remote_address);
        cout<<"b"<<endl;
    }
    else {
        /// It is more memory-efficient to write over the intervening space with null values
        while (remote_delta-- > 0) {
            swaths.back().data.push_back(byte_with_flags{0, 0});
            cout << "c" << endl;
        }
    }
    swaths.back().data.push_back(byte_with_flags{3, 2});
}


/* Entry point */
int
main()
{
    // Measure
    high_resolution_clock::time_point timestamp;

    size_t i;
    size_t i_count = 121065475;
    size_t remote_address = 0x100;

    timestamp = high_resolution_clock::now();
    for(i = 0; i < i_count; i++, remote_address++) {
        add_element(remote_address);
    }
    clog<<"Scan 1 done in: "<<duration_cast<duration<double>>(high_resolution_clock::now() - timestamp).count()<<endl;



    swaths.back().data.clear();
    swaths.back().data.shrink_to_fit();

    timestamp = high_resolution_clock::now();
    for(i = 0; i < i_count; i++, remote_address++) {
        swaths.back().data.push_back(byte_with_flags{3, 2});
    }
    clog<<"Scan 2 done in: "<<duration_cast<duration<double>>(high_resolution_clock::now() - timestamp).count()<<endl;



    swaths.back().data.clear();
    swaths.back().data.shrink_to_fit();
    swath_t &swaths_back = swaths.back();

    timestamp = high_resolution_clock::now();
    for(i = 0; i < i_count; i++, remote_address++) {
        swaths_back.data.push_back(byte_with_flags{3, 2});
    }
    clog<<"Scan 3 done in: "<<duration_cast<duration<double>>(high_resolution_clock::now() - timestamp).count()<<endl;



    swaths.back().data.clear();
    swaths.back().data.shrink_to_fit();
    vector<byte_with_flags> &swaths_back_data = swaths.back().data;

    timestamp = high_resolution_clock::now();
    for(i = 0; i < i_count; i++, remote_address++) {
        swaths_back_data.push_back(byte_with_flags{3, 2});
    }
    clog<<"Scan 4 done in: "<<duration_cast<duration<double>>(high_resolution_clock::now() - timestamp).count()<<endl;



    vector<byte_with_flags> data;

    timestamp = high_resolution_clock::now();
    for(i = 0; i < i_count; i++, remote_address++) {
        data.push_back(byte_with_flags{3, 2});
    }
    clog<<"Scan 5 done in: "<<duration_cast<duration<double>>(high_resolution_clock::now() - timestamp).count()<<endl;

    return 0;
}