xoshiro
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A pseudo random number generator
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# Xoshiro
[](https://badge.fury.io/js/xoshiro)
## What is this?
A pseudo-random-number-generator module implemented in N-API. [Here](http://prng.di.unimi.it/) is all about the algorithms.
## Requirements
- [CMake](http://www.cmake.org/download/)
- A proper C/C++ compiler toolchain of the given platform
- **Windows**:
- [Visual C++ Build Tools](https://visualstudio.microsoft.com/visual-cpp-build-tools/)
or a recent version of Visual C++ will do ([the free Community](https://www.visualstudio.com/products/visual-studio-community-vs) version works well)
- **Unix/Posix**:
- Clang or GCC
- Make
## Installation
Just run this command:
```shell script
npm install --save xoshiro
```
## Usage
```javascript
const xoshiro = require('xoshiro');
const crypto = require('crypto');
// create a PRNG with an algorithm and a seed
const seed = crypto.randomBytes(32);
const prng = xoshiro.create('256+', seed);
// generate a random unsigned 32-bit integer
console.log(prng.roll());
// store the current state
const s = prng.state
// generate a random number
const x = prng.roll()
// restore the state
prng.state = s
// generate a random number from the previous state
const y = prng.roll()
// and they should be equal
console.log(x === y) // -> true
```
### Supported algorithms
- `'256+'` __xoshiro256+__, requires the seed to be of at least 32 bytes
- `'256++'` __xoshiro256++__, requires the seed to be of at least 32 bytes
- `'256**'` __xoshiro256**__, requires the seed to be of at least 32 bytes
- `'512+'` __xoshiro512+__, requires the seed to be of at least 64 bytes
- `'512++'` __xoshiro512++__, requires the seed to be of at least 64 bytes
- `'512**'` __xoshiro512**__, requires the seed to be of at least 64 bytes
Note: In order to make it work, the seed used to initialize the PRNG should not be all 0's.