A leg workout machine for homes.

I call it KneeCruncher.

catchupzone updated view

 

Catcup.zone (some html/js/php related work I am doing)

 

SQL injection flaw and how to fix it at DB itself

 

One simple example is 

Select * from Users where email = '$email' ;

Here $email could be substituted with an "OR" getting a positive result for the condition check.

$email could be ' OR '1'='1 (including the single quotes), making this a valid SQL Statement. 

However, In DB we could add a SQL Command template for the SQL statement, and if the template doesn't match then the SQL statement doesn't get executed. 

email_value = web_input;

db->connection(""" , '"", 5000);

db->set_statement (" Select * from Users where email = '"+ email_value +" ';");

db->set_valid_template( " select * from Users where email = '%'; "); 

// where % represents a value that is added dynamically. 

if( db->is_injected() ){

    //SQL injection detected

    //return error.

} else {

    //SQL injection not detected

    // continue on here ...

}

Instead of fixing this in a website (backend pages) this could be fixed in the DB parser level itself, making one of the security vulnerabilities fixed.

Or, something like this can be done.

db->check_sql( email_value ) 

//0 - not sql

//1 - partial sql statement

//2 - full sql statement

Both of these methods wouldn't require a db query to be done.

I had to put it out there

 

Power of 2 : Updated

 Here is the correct algorithm, basically it wasn't taking 1 as input properly.

#include <iostream>

#include <thread>

#include <chrono>

using namespace std;

uint64_t powerxxx(int x, int n) {

if (n <= 0) {

if (n == 0)

return 1;

else

    return 0;

}

int modval = n & 0x01;

if (modval == 1)

n--;

int count = (n >> 1);

int powertwo = x*x;

uint64_t power = 1;

while (count > 0)

{

power *= powertwo;

count--;

}

if (modval == 1)

power *= x;

return power;

}

int main()

{

auto start = std::chrono::system_clock::now();

uint64_t p = pow(3, 33);

auto end = std::chrono::system_clock::now();

std::chrono::duration<long double> diff = end - start;

std::cout << "power = " << p << ": " << diff.count() << " s\n";

start = std::chrono::system_clock::now();

p = powerxxx(3, 33);

end = std::chrono::system_clock::now();

diff = end - start;

std::cout <<"power = "<<p <<": " << diff.count() << " s\n";

return 0;

}

Power of 2 : :)

This is a new algorithm to calculate pow(x, n), where it calculates nth power of x. According to Chrono it is faster than the system pow(x,n).

#include <iostream>

#include <chrono>

using namespace std;

uint64_t powerxxx(int x, int n) {

int count  = 0;

int modval = n & 0x01;

if (modval == 1)

n = n - 1;

if (n == 0)

return 1;

else if (n < 0)

return 0;

count = (n >> 1);

int powertwo = x*x;

uint64_t power = 1;

while (count > 0)

{

power *= powertwo;

count--;

}

if (modval == 1)

power *= x;

return power;

}

int main()

{

auto start = std::chrono::system_clock::now();

uint64_t p = pow(3, 33);

auto end = std::chrono::system_clock::now();

std::chrono::duration<double> diff = end - start;

std::cout << "power = " << p << ": " << diff.count() << " s\n";

start = std::chrono::system_clock::now();

p = powerxxx(3, 33);

end = std::chrono::system_clock::now();

diff = end - start;

std::cout <<"power = "<<p <<": " << diff.count() << " s\n";

    return 0;

}