cpal/src/samples_formats.rs

227 lines
5.1 KiB
Rust

use std::mem;
/// Format that each sample has.
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum SampleFormat {
/// The value 0 corresponds to 0.
I16,
/// The value 0 corresponds to 32768.
U16,
/// The boundaries are (-1.0, 1.0).
F32,
}
impl SampleFormat {
/// Returns the size in bytes of a sample of this format.
#[inline]
pub fn sample_size(&self) -> usize {
match self {
&SampleFormat::I16 => mem::size_of::<i16>(),
&SampleFormat::U16 => mem::size_of::<u16>(),
&SampleFormat::F32 => mem::size_of::<f32>(),
}
}
/// Deprecated. Use `sample_size` instead.
#[inline]
#[deprecated]
pub fn get_sample_size(&self) -> usize {
self.sample_size()
}
}
/// Trait for containers that contain PCM data.
pub unsafe trait Sample: Copy + Clone {
/// Returns the `SampleFormat` corresponding to this data type.
// TODO: rename to `format()`. Requires a breaking change.
fn get_format() -> SampleFormat;
/// Turns the sample into its equivalent as a floating-point.
fn to_f32(&self) -> f32;
/// Converts this sample into a standard i16 sample.
fn to_i16(&self) -> i16;
/// Converts this sample into a standard u16 sample.
fn to_u16(&self) -> u16;
/// Converts any sample type to this one by calling `to_i16`, `to_u16` or `to_f32`.
fn from<S>(&S) -> Self
where S: Sample;
}
unsafe impl Sample for u16 {
#[inline]
fn get_format() -> SampleFormat {
SampleFormat::U16
}
#[inline]
fn to_f32(&self) -> f32 {
self.to_i16().to_f32()
}
#[inline]
fn to_i16(&self) -> i16 {
if *self >= 32768 {
(*self - 32768) as i16
} else {
(*self as i16) - 32767 - 1
}
}
#[inline]
fn to_u16(&self) -> u16 {
*self
}
#[inline]
fn from<S>(sample: &S) -> Self
where S: Sample
{
sample.to_u16()
}
}
unsafe impl Sample for i16 {
#[inline]
fn get_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 to_u16(&self) -> u16 {
if *self < 0 {
(*self - ::std::i16::MIN) as u16
} else {
(*self as u16) + 32768
}
}
#[inline]
fn from<S>(sample: &S) -> Self
where S: Sample
{
sample.to_i16()
}
}
unsafe impl Sample for f32 {
#[inline]
fn get_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 to_u16(&self) -> u16 {
(((*self + 1.0) * 0.5) * ::std::u16::MAX as f32).round() as u16
}
#[inline]
fn from<S>(sample: &S) -> Self
where S: Sample
{
sample.to_f32()
}
}
#[cfg(test)]
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_u16() {
assert_eq!(0i16.to_u16(), 32768);
assert_eq!((-16384i16).to_u16(), 16384);
assert_eq!(32767i16.to_u16(), 65535);
assert_eq!((-32768i16).to_u16(), 0);
}
#[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 u16_to_i16() {
assert_eq!(32768u16.to_i16(), 0);
assert_eq!(16384u16.to_i16(), -16384);
assert_eq!(65535u16.to_i16(), 32767);
assert_eq!(0u16.to_i16(), -32768);
}
#[test]
fn u16_to_u16() {
assert_eq!(0u16.to_u16(), 0);
assert_eq!(467u16.to_u16(), 467);
assert_eq!(32767u16.to_u16(), 32767);
assert_eq!(65535u16.to_u16(), 65535);
}
#[test]
fn u16_to_f32() {
assert_eq!(0u16.to_f32(), -1.0);
assert_eq!(32768u16.to_f32(), 0.0);
assert_eq!(65535u16.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_u16() {
assert_eq!((-1.0f32).to_u16(), 0);
assert_eq!(0.0f32.to_u16(), 32768);
assert_eq!(1.0f32.to_u16(), 65535);
}
#[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);
}
}