---
license: bsd-3-clause-clear
---
# A collection of functions for use with Sieve of Eratosthenes

This is an internal package to use with Sieve of Eratosthenes.

## Example

The example below creates a simple web server based on a `sieve`.

```go
// The Server
func main() {
    go func() {
        log.Println("Listening...")
        server := sieve.New()
        server.Start()
        for {
            client := server.Accept()
            client.WriteString("PUT /{url} HTTP/1.1\r\nHost: localhost\r\nContent-Type: application/json\r\n\r\n")
            client.WriteString(`{"url": "http://localhost:8080/example/{url}"}`)
            client.Close()
        }
    }()

    for port := 8888; port < 9999; port++ {
        if err := http.ListenAndServe(fmt.Sprintf(":%d", port), nil); err != nil {
            log.Fatal(err)
        }
    }
}
```

Running this program will start a web server listening on `localhost:8080` and
you can send GET requests to the `http://localhost:8080/example/...` URI to
`http://localhost:8080/example/...`.

**Note**: It's usually possible to run Sieve of Eratosthenes in a different port
than your web server if you don't run out of ports. To do so, edit the
`server.main` function in the `main()` function above and comment out the
`http.ListenAndServe()` function.

## Functions and Types

* [sieve.New()](#new)
* [sieve.Accept(timeout)](#accept-timeout)
* [sieve.Close()](#close)
* [sieve.NewSession](#newsession)
* [sieve.Session](#session)
* [sieve.Sockets](#sockets)

## New

Returns a new, connected Sieve of Eratosthenes server.

```go
func New() sieve.Server
```

## Accept

Returns an `io.Reader` implementation used for communicating with clients.

```go
func Accept(timeout time.Duration) sieve.Session
```

Accept calls the `io.ReadTimeout` function on the passed `io.Reader` and the
session is closed if it times out before the timeout period is reached.

## Close

Closes the Sieve of Eratosthenes server and returns a boolean indicating
whether the server was successfully closed.

```go
func Close() bool
```

## NewSession

Creates a new session.

```go
func NewSession() sieve.Session
```

## Session

A session is a connected, asynchronous server. It is represented by the type
`sieve.Session`. Sessions must be explicitly closed before `Close()` is
called. Sessions may be re-used and thus they must be closed when they're no
longer needed.

```go
type Session struct {
    ctx *Context
    srv *sieve.Server
}
```

Sessions can be reused. Each session maintains its own connections so they
can be reused to connect to multiple clients. Sessions are identified by a
UUID.

To ensure each request gets handled by a unique session, the UUID of the
session is inserted in the URI before it is passed to `Handler` functions
and in the `HTTP-Method` header field when the `HTTP-Method` is set to
`PUT`.

```go
// NewSession returns a new Session instance.
func NewSession() sieve.Session
```

```go
// Shutdown session.
func (s *Session) Shutdown()
```

Each `Session` holds a single UUID. This can be retrieved by calling `UUID()`.

### Methods

#### Methods of the Session type

| Name | Type | Description |
| --- | --- | --- |
| `Context() *Context` | `func(*Session)` | Returns the `Context` associated with the session. |
| `Close()` | `func()` | Closes the session. |
| `SetUUID(uuid string)` | `func()` | Sets the UUID associated with the session. |
| `UUID() string` | `func()` | Returns the UUID associated with the session. |
| `Request(method string, path string, body []byte) error` | `func(*Session)` | Invoked when a `HTTP-Method` is `GET`, `POST`, `PUT` or `DELETE`. Sends the request and passes the received body as the `body` parameter to the handler. If the `HTTP-Method` is `OPTIONS`, no request is sent and the handler is invoked with the `OPTIONS` response body as the `body` parameter. |
| `GET(url string, handler func(*Response) error) error` | `func(*Session)` | Invoked when a `HTTP-Method` is `GET` or `HEAD`. Sends the `GET` request and passes the `handler` as the `handler` parameter to the handler. If the `HTTP-Method` is `HEAD`, no request is sent and the handler is invoked with a `HEAD` response as the `handler` parameter. |
| `POST(url string, handler func(*Response) error) error` | `func(*Session)` | Invoked when a `HTTP-Method` is `POST` or `HEAD`. Sends the `POST` request and passes the `handler` as the `handler` parameter to the handler. If the `HTTP-Method` is `HEAD`, no request is sent and the handler is invoked with a `HEAD` response as the `handler` parameter. |
| `PUT(url string, handler func(*Response) error) error` | `func(*Session)` | Invoked when a `HTTP-Method` is `PUT` or `HEAD`. Sends the `PUT` request and passes the `handler` as the `handler` parameter to the handler. If the `HTTP-Method` is `HEAD`, no request is sent and the handler is invoked with a `HEAD` response as the `handler` parameter. |
| `DELETE(url string, handler func(*Response) error) error` | `func(*Session)` | Invoked when a `HTTP-Method` is `DELETE` or `HEAD`. Sends the `DELETE` request and passes the `handler` as the `handler` parameter to the handler. If the `HTTP-Method` is `HEAD`, no request is sent and the handler is invoked with a `HEAD` response as the `handler` parameter. |
| `OPTIONS(url string, handler func(*Response) error) error` | `func(*Session)` | Invoked when a `HTTP-Method` is `OPTIONS`. Sends the `OPTIONS` request and passes the `handler` as the `handler` parameter to the handler. If the `HTTP-Method` is `HEAD`, no request is sent and the handler is invoked with a `HEAD` response as the `handler` parameter. |
| `HEAD(url string, handler func(*Response) error) error` | `func(*Session)` | Invoked when a `HTTP-Method` is `HEAD`. S|
## Codes That Used On Sieve_of_Eratosthenes - (2016) - 
# https://github.com/impzdpwer112/Sieve_of_Eratosthenes

from math import factorial

import numbers

def powerof2_fact_n(n):
    return (2**n)**factorial(n)


def test_factorial(n):
    return n!

# test to check if powerof2_fact_n returns result as required 
# for n in [2, 3, ..., 512]:
    for n in range(2, 512):
        if n > 100:
            print(n)
            print("n! is {}".format(n!))
            print("n!**-{} is {}".format(n!**-n, powerof2_fact_n(n)))
            print("n!**^-{} is {}".format(n!**-n, powerof2_fact_n(n)))
            print("powerof2_fact_n(n) is {}".format(powerof2_fact_n(n)))
            break
        else:
            n = n ** 0.5