reorders packets in pcap file

#include <stdint.h>
#include <iostream>
#include <sstream>

typedef struct pcap_hdr_s {
        uint32_t magic_number;   /* magic number */
        uint16_t version_major;  /* major version number */
        uint16_t version_minor;  /* minor version number */
        int32_t  thiszone;       /* GMT to local correction */
        uint32_t sigfigs;        /* accuracy of timestamps */
        uint32_t snaplen;        /* max length of captured packets, in octets */
        uint32_t network;        /* data link type */
} pcap_hdr_t;

typedef struct pcaprec_hdr_s {
        uint32_t ts_sec;         /* timestamp seconds */
        uint32_t ts_usec;        /* timestamp microseconds */
        uint32_t incl_len;       /* number of octets of packet saved in file */
        uint32_t orig_len;       /* actual length of packet */
} pcaprec_hdr_t;


std::istream& operator>>(std::istream& istr, const pcaprec_hdr_t& t) {
	istr.read(( char*) &t, sizeof(pcaprec_hdr_t));
	return istr;
}


std::ostream& operator<<(std::ostream& istr, const pcaprec_hdr_t& t) {
	istr.write((const char*) &t, sizeof(pcaprec_hdr_t));
	return istr;
}

std::istream& operator>>(std::istream& istr, const pcap_hdr_t& t) {
	istr.read(( char*) &t, sizeof(pcap_hdr_t));
	return istr;
}


std::ostream& operator<<(std::ostream& istr, const pcap_hdr_t& t) {
	istr.write((const char*) &t, sizeof(pcap_hdr_t));
	return istr;
}


void grab_record(std::istream& istr, std::ostream& ostr, const pcaprec_hdr_t& rec)	{

	ostr << rec;

	char* buffer = new char[ rec.incl_len ];

	istr.read(buffer, rec.incl_len);
	ostr.write(buffer, rec.incl_len);

	delete[] buffer;

}

int main(int argc , const char** argv) {

	if (argc != 3) {
		std::cerr << "wrong number of args\n";
		return 1;
	}

	int first_packet = std::atoi(argv[1]);
	int second_packet = std::atoi(argv[2]);

	if (first_packet >= second_packet) {
		std::cerr << "packets are wrong\n";
		return 1;
	}

	pcap_hdr_t header;
	pcaprec_hdr_t record;

	pcaprec_hdr_t record1;
	pcaprec_hdr_t record2;
	


	std::cin >> header;
	std::cout << header;

	int current_packet=0;

	std::ostringstream ostrstr;

	while (std::cin >> record) {

		if (current_packet == second_packet ) {

			std::cerr << "swapping packets\n";
			grab_record(std::cin , std::cout, record);
			std::cout << ostrstr.str();
			

		} else if (current_packet >= first_packet && current_packet < second_packet) {

			std::cerr << "diverting packets\n";
			grab_record(std::cin , ostrstr, record);

		} else {

			std::cerr << "transferring packets\n";
			grab_record(std::cin , std::cout, record);


		}

		current_packet++;
	}


	return 0;
}