use std::mem;
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum SampleFormat {
I16,
F32,
}
pub unsafe trait Sample: Copy + Clone {
const FORMAT: SampleFormat;
fn to_f32(&self) -> f32;
fn to_i16(&self) -> i16;
fn from<S>(sample: &S) -> Self
where
S: Sample;
}
unsafe impl Sample for i16 {
const FORMAT: SampleFormat = SampleFormat::I16;
#[inline]
fn to_f32(&self) -> f32 {
if *self < 0 {
*self as f32 / -(::std::i16::MIN as f32)
} else {
*self as f32 / ::std::i16::MAX as f32
}
}
#[inline]
fn to_i16(&self) -> i16 {
*self
}
#[inline]
fn from<S>(sample: &S) -> Self
where
S: Sample,
{
sample.to_i16()
}
}
unsafe impl Sample for f32 {
const FORMAT: SampleFormat = SampleFormat::F32;
#[inline]
fn to_f32(&self) -> f32 {
*self
}
#[inline]
fn to_i16(&self) -> i16 {
if *self >= 0.0 {
(*self * ::std::i16::MAX as f32) as i16
} else {
(-*self * ::std::i16::MIN as f32) as i16
}
}
#[inline]
fn from<S>(sample: &S) -> Self
where
S: Sample,
{
sample.to_f32()
}
}
#[cfg(test)]
#[allow(clippy::float_cmp)]
mod test {
use super::Sample;
#[test]
fn i16_to_i16() {
assert_eq!(0i16.to_i16(), 0);
assert_eq!((-467i16).to_i16(), -467);
assert_eq!(32767i16.to_i16(), 32767);
assert_eq!((-32768i16).to_i16(), -32768);
}
#[test]
fn i16_to_f32() {
assert_eq!(0i16.to_f32(), 0.0);
assert_eq!((-16384i16).to_f32(), -0.5);
assert_eq!(32767i16.to_f32(), 1.0);
assert_eq!((-32768i16).to_f32(), -1.0);
}
#[test]
fn f32_to_i16() {
assert_eq!(0.0f32.to_i16(), 0);
assert_eq!((-0.5f32).to_i16(), ::std::i16::MIN / 2);
assert_eq!(1.0f32.to_i16(), ::std::i16::MAX);
assert_eq!((-1.0f32).to_i16(), ::std::i16::MIN);
}
#[test]
fn f32_to_f32() {
assert_eq!(0.1f32.to_f32(), 0.1);
assert_eq!((-0.7f32).to_f32(), -0.7);
assert_eq!(1.0f32.to_f32(), 1.0);
}
}