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83 lines
1.3 KiB
83 lines
1.3 KiB
extern crate getrandom;
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use getrandom::*;
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn it_works() {
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let mut f: f64 = 0.0;
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assert_eq!(sample(&mut f as *mut f64), 1);
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}
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#[test]
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fn bytes_works() {
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let mut buf: [u8; 16] = [0; 16];
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assert_eq!(bytes(&mut buf[0] as *mut u8, 16), 1);
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}
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}
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fn get<T: Default>() -> Result<T, Error>
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{
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let mut value: T = Default::default();
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unsafe {
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let mut slice = std::slice::from_raw_parts_mut(&mut value as *mut T as *mut u8, std::mem::size_of::<T>());
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populate(&mut slice)?;
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}
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Ok(value)
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}
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fn double() -> Result<f64, Error>
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{
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let long: i64 = get::<i64>()?;
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Ok( ((long & ((1i64 << 53) - 1)) as f64) * (1_f64 / ((1_i64 << 53) as f64)))
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}
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fn populate(mut value: &mut [u8]) -> Result<(), Error>
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{
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getrandom(&mut value)?;
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Ok(())
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}
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#[no_mangle]
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pub extern "C" fn sample(value: *mut f64) -> i32
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{
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match std::panic::catch_unwind(|| {
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unsafe {
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match double() {
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Ok(x) => *value = x,
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Err(_) => return 0,
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}
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}
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1
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}) {
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Ok(v) => v,
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Err(_) => 0,
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}
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}
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#[no_mangle]
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pub extern "C" fn bytes(value: *mut u8, size: i32) -> i32
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{
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let mut buf: &mut [u8];
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if size < 0 {
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return 0
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}
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unsafe {
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buf = std::slice::from_raw_parts_mut(value, size as usize);
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}
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match getrandom(&mut buf) {
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Ok(_) => 1,
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Err(_) => 0,
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}
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}
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