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// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// https://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

//! The implementations of the `Uniform` distribution for integer types.

use {Rng};
use distributions::{Distribution, Uniform};

impl Distribution<isize> for Uniform {
    #[inline]
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> isize {
        rng.gen::<usize>() as isize
    }
}

impl Distribution<i8> for Uniform {
    #[inline]
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> i8 {
        rng.next_u32() as i8
    }
}

impl Distribution<i16> for Uniform {
    #[inline]
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> i16 {
        rng.next_u32() as i16
    }
}

impl Distribution<i32> for Uniform {
    #[inline]
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> i32 {
        rng.next_u32() as i32
    }
}

impl Distribution<i64> for Uniform {
    #[inline]
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> i64 {
        rng.next_u64() as i64
    }
}

#[cfg(feature = "i128_support")]
impl Distribution<i128> for Uniform {
    #[inline]
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> i128 {
        rng.gen::<u128>() as i128
    }
}

impl Distribution<usize> for Uniform {
    #[inline]
    #[cfg(any(target_pointer_width = "32", target_pointer_width = "16"))]
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> usize {
        rng.next_u32() as usize
    }

    #[inline]
    #[cfg(target_pointer_width = "64")]
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> usize {
        rng.next_u64() as usize
    }
}

impl Distribution<u8> for Uniform {
    #[inline]
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> u8 {
        rng.next_u32() as u8
    }
}

impl Distribution<u16> for Uniform {
    #[inline]
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> u16 {
        rng.next_u32() as u16
    }
}

impl Distribution<u32> for Uniform {
    #[inline]
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> u32 {
        rng.next_u32()
    }
}

impl Distribution<u64> for Uniform {
    #[inline]
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> u64 {
        rng.next_u64()
    }
}

#[cfg(feature = "i128_support")]
impl Distribution<u128> for Uniform {
    #[inline]
    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> u128 {
        // Use LE; we explicitly generate one value before the next.
        let x = rng.next_u64() as u128;
        let y = rng.next_u64() as u128;
        (y << 64) | x
    }
}


#[cfg(test)]
mod tests {
    use Rng;
    use distributions::{Uniform};
    
    #[test]
    fn test_integers() {
        let mut rng = ::test::rng(806);
        
        rng.sample::<isize, _>(Uniform);
        rng.sample::<i8, _>(Uniform);
        rng.sample::<i16, _>(Uniform);
        rng.sample::<i32, _>(Uniform);
        rng.sample::<i64, _>(Uniform);
        #[cfg(feature = "i128_support")]
        rng.sample::<i128, _>(Uniform);
        
        rng.sample::<usize, _>(Uniform);
        rng.sample::<u8, _>(Uniform);
        rng.sample::<u16, _>(Uniform);
        rng.sample::<u32, _>(Uniform);
        rng.sample::<u64, _>(Uniform);
        #[cfg(feature = "i128_support")]
        rng.sample::<u128, _>(Uniform);
    }
}