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pub mod system;
use std::time::SystemTime;
use super::flag::Flag;
pub const RAND_MAX: usize = 32767;
#[derive(Copy, Clone, Debug)]
pub struct BaseRand {
seed: usize,
function: Flag,
}
impl BaseRand {
pub fn new() -> Self {
BaseRand {
seed: time_get(),
function: Flag::On(0),
}
}
pub fn srand(&mut self, seed: usize) {
self.seed = seed;
}
pub fn set_function(&mut self, style: &str) {
match style {
"pmrand" => self.function = Flag::On(1),
"basic" => self.function = Flag::On(0),
_ => self.function = Flag::new(),
}
}
pub fn lazy_srand(&mut self) {
self.srand(time_get());
}
pub fn rand(&mut self) -> usize {
let func = self.function;
let mut _seed = self.seed;
let mut result = 0;
if let Flag::On(e) = func {
match e {
0 => result = basic(&mut _seed),
1 => result = pmrand(&mut _seed),
_ => result = lazy(&mut _seed),
}
} else {
result = lazy(&mut _seed);
}
self.srand(_seed);
result
}
pub fn get_seed(&self) -> usize {
self.seed
}
}
impl Default for BaseRand {
fn default() -> Self {
Self::new()
}
}
fn basic(seed: &mut usize) -> usize {
let mut _seed = *seed as u32;
_seed = (((_seed as u64 * 1103515245) as u32) as u64 + 12345) as u32;
*seed = _seed as usize;
(_seed as usize) >> 16 & RAND_MAX
}
fn lazy(seed: &mut usize) -> usize {
_pmrand(seed, 16807)
}
fn pmrand(seed: &mut usize) -> usize {
_pmrand(seed, 48271)
}
fn _pmrand(seed: &mut usize, a: u64) -> usize {
let mut _seed = *seed as u64;
let m: u64 = 2147483647;
let q = m / a;
let r = m % a;
let hi = _seed / q;
let lo = _seed % q;
let test = a * lo - r * hi;
if test > 0 {
_seed = test;
} else {
_seed = test + m;
}
_seed %= RAND_MAX as u64;
*seed = _seed as usize;
_seed as usize
}
#[doc(hidden)]
fn time_get() -> usize {
let foo_string = format!("{:?}", SystemTime::now());
let mut seed: usize = 0;
let mut flag = Flag::new();
for num in foo_string.chars() {
match num {
e @ '0'...'9' => {
flag.on(None);
seed = seed * 10 + (e as u8 - 48) as usize;
if seed >= usize::max_value() / 10 - 10 {
break;
}
}
_ => {
if flag.is_on() {
break;
}
}
}
}
seed
}