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// Copyright 2017 Lyndon Brown
//
// This file is part of the PulseAudio Rust language binding.
//
// Licensed under the MIT license or the Apache license (version 2.0), at your option. You may not
// copy, modify, or distribute this file except in compliance with said license. You can find copies
// of these licenses either in the LICENSE-MIT and LICENSE-APACHE files, or alternatively at
// <http://opensource.org/licenses/MIT> and <http://www.apache.org/licenses/LICENSE-2.0>
// respectively.
//
// Portions of documentation are copied from the LGPL 2.1+ licensed PulseAudio C headers on a
// fair-use basis, as discussed in the overall project readme (available in the git repository).
//! Constants and routines for handing channel mapping.
//!
//! # Overview
//!
//! Channel maps provide a way to associate channels in a stream with a specific speaker position.
//! This relieves applications of having to make sure their channel order is identical to the final
//! output.
//!
//! # Initialisation
//!
//! A channel map consists of an array of [`Position`] values, one for each channel. This array is
//! stored together with a channel count in a [`Map`] structure.
//!
//! Before filling the structure, the application must initialise it using [`Map::init()`]. There
//! are also a number of convenience functions for standard channel mappings:
//!
//! * [`Map::init_mono()`]: Create a channel map with only mono audio.
//! * [`Map::init_stereo()`]: Create a standard stereo mapping.
//! * [`Map::init_auto()`]: Create a standard channel map for a specific number of channels.
//! * [`Map::init_extend()`]: Similar to [`Map::init_auto()`] but synthesize a channel map if no
//! predefined one is known for the specified number of channels.
use std::borrow::{Borrow, BorrowMut};
use std::ffi::{CStr, CString};
use std::borrow::Cow;
use num_derive::{FromPrimitive, ToPrimitive};
use crate::sample;
pub use capi::pa_channel_map_def_t as MapDef;
/// A mask of channel positions.
pub type PositionMask = capi::channelmap::pa_channel_position_mask_t;
/// Position mask covering all positions.
pub const POSITION_MASK_ALL: PositionMask = 0xffffffffffffffffu64;
/// A list of channel labels.
///
/// Note, certain aliases, specifically `Left`, `Right`, `Center` and `Subwoofer`, available in the
/// equivalent C enum are not provided here, since Rust does not allow aliases.
#[repr(C)]
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
#[derive(FromPrimitive, ToPrimitive)]
pub enum Position {
/* NOTE: This enum’s variants and variant values **must** remain identical to the `sys` crate
(C API) equivalent */
/// Invalid.
Invalid = -1,
/// Mono.
Mono = 0,
/// Apple, Dolby call this ‘Left’.
FrontLeft,
/// Apple, Dolby call this ‘Right’.
FrontRight,
/// Apple, Dolby call this ‘Center’.
FrontCenter,
/// Microsoft calls this ‘Back Center’, Apple calls this ‘Center Surround’,
/// Dolby calls this ‘Surround Rear Center’.
RearCenter,
/// Microsoft calls this ‘Back Left’, Apple calls this ‘Left Surround’,
/// Dolby calls this ‘Surround Rear Left’.
RearLeft,
/// Microsoft calls this ‘Back Right’, Apple calls this ‘Right Surround’,
/// Dolby calls this ‘Surround Rear Right’.
RearRight,
/// Aka subwoofer. Microsoft calls this ‘Low Frequency’,
/// Apple calls this ‘LFEScreen’.
Lfe,
/// Apple, Dolby call this ‘Left Center’.
FrontLeftOfCenter,
/// Apple, Dolby call this ‘Right Center’.
FrontRightOfCenter,
/// Apple calls this ‘Left Surround Direct’,
/// Dolby calls this ‘Surround Left’.
SideLeft,
/// Apple calls this ‘Right Surround Direct’,
/// Dolby calls this ‘Surround Right’.
SideRight,
/// Auxillary 0.
Aux0,
/// Auxillary 1.
Aux1,
/// Auxillary 2.
Aux2,
/// Auxillary 3.
Aux3,
/// Auxillary 4.
Aux4,
/// Auxillary 5.
Aux5,
/// Auxillary 6.
Aux6,
/// Auxillary 7.
Aux7,
/// Auxillary 8.
Aux8,
/// Auxillary 9.
Aux9,
/// Auxillary 10.
Aux10,
/// Auxillary 11.
Aux11,
/// Auxillary 12.
Aux12,
/// Auxillary 13.
Aux13,
/// Auxillary 14.
Aux14,
/// Auxillary 15.
Aux15,
/// Auxillary 16.
Aux16,
/// Auxillary 17.
Aux17,
/// Auxillary 18.
Aux18,
/// Auxillary 19.
Aux19,
/// Auxillary 20.
Aux20,
/// Auxillary 21.
Aux21,
/// Auxillary 22.
Aux22,
/// Auxillary 23.
Aux23,
/// Auxillary 24.
Aux24,
/// Auxillary 25.
Aux25,
/// Auxillary 26.
Aux26,
/// Auxillary 27.
Aux27,
/// Auxillary 28.
Aux28,
/// Auxillary 29.
Aux29,
/// Auxillary 30.
Aux30,
/// Auxillary 31.
Aux31,
/// Apple calls this ‘Top Center Surround’.
TopCenter,
/// Apple calls this ‘Vertical Height Left’.
TopFrontLeft,
/// Apple calls this ‘Vertical Height Right’.
TopFrontRight,
/// Apple calls this ‘Vertical Height Center’.
TopFrontCenter,
/// Microsoft and Apple call this ‘Top Back Left’.
TopRearLeft,
/// Microsoft and Apple call this ‘Top Back Right’.
TopRearRight,
/// Microsoft and Apple call this ‘Top Back Center’.
TopRearCenter,
}
impl Default for Position {
#[inline(always)]
fn default() -> Self {
Position::Invalid
}
}
/// Check is equal to `sys` equivalent
#[test]
fn pos_compare_capi() {
assert_eq!(std::mem::size_of::<Position>(), std::mem::size_of::<capi::pa_channel_position_t>());
assert_eq!(std::mem::align_of::<Position>(), std::mem::align_of::<capi::pa_channel_position_t>());
// Check order and value of variants match
// No point checking conversions in both directions since both are a transmute
assert_eq!(Position::Invalid, Position::from(capi::pa_channel_position_t::Invalid));
assert_eq!(Position::Mono, Position::from(capi::pa_channel_position_t::Mono));
assert_eq!(Position::FrontLeft, Position::from(capi::pa_channel_position_t::FrontLeft));
assert_eq!(Position::FrontRight, Position::from(capi::pa_channel_position_t::FrontRight));
assert_eq!(Position::FrontCenter, Position::from(capi::pa_channel_position_t::FrontCenter));
assert_eq!(Position::RearCenter, Position::from(capi::pa_channel_position_t::RearCenter));
assert_eq!(Position::RearLeft, Position::from(capi::pa_channel_position_t::RearLeft));
assert_eq!(Position::RearRight, Position::from(capi::pa_channel_position_t::RearRight));
assert_eq!(Position::Lfe, Position::from(capi::pa_channel_position_t::Lfe));
assert_eq!(Position::FrontLeftOfCenter, Position::from(capi::pa_channel_position_t::FrontLeftOfCenter));
assert_eq!(Position::FrontRightOfCenter, Position::from(capi::pa_channel_position_t::FrontRightOfCenter));
assert_eq!(Position::SideLeft, Position::from(capi::pa_channel_position_t::SideLeft));
assert_eq!(Position::SideRight, Position::from(capi::pa_channel_position_t::SideRight));
assert_eq!(Position::Aux0, Position::from(capi::pa_channel_position_t::Aux0));
assert_eq!(Position::Aux1, Position::from(capi::pa_channel_position_t::Aux1));
assert_eq!(Position::Aux2, Position::from(capi::pa_channel_position_t::Aux2));
assert_eq!(Position::Aux3, Position::from(capi::pa_channel_position_t::Aux3));
assert_eq!(Position::Aux4, Position::from(capi::pa_channel_position_t::Aux4));
assert_eq!(Position::Aux5, Position::from(capi::pa_channel_position_t::Aux5));
assert_eq!(Position::Aux6, Position::from(capi::pa_channel_position_t::Aux6));
assert_eq!(Position::Aux7, Position::from(capi::pa_channel_position_t::Aux7));
assert_eq!(Position::Aux8, Position::from(capi::pa_channel_position_t::Aux8));
assert_eq!(Position::Aux9, Position::from(capi::pa_channel_position_t::Aux9));
assert_eq!(Position::Aux10, Position::from(capi::pa_channel_position_t::Aux10));
assert_eq!(Position::Aux11, Position::from(capi::pa_channel_position_t::Aux11));
assert_eq!(Position::Aux12, Position::from(capi::pa_channel_position_t::Aux12));
assert_eq!(Position::Aux13, Position::from(capi::pa_channel_position_t::Aux13));
assert_eq!(Position::Aux14, Position::from(capi::pa_channel_position_t::Aux14));
assert_eq!(Position::Aux15, Position::from(capi::pa_channel_position_t::Aux15));
assert_eq!(Position::Aux16, Position::from(capi::pa_channel_position_t::Aux16));
assert_eq!(Position::Aux17, Position::from(capi::pa_channel_position_t::Aux17));
assert_eq!(Position::Aux18, Position::from(capi::pa_channel_position_t::Aux18));
assert_eq!(Position::Aux19, Position::from(capi::pa_channel_position_t::Aux19));
assert_eq!(Position::Aux20, Position::from(capi::pa_channel_position_t::Aux20));
assert_eq!(Position::Aux21, Position::from(capi::pa_channel_position_t::Aux21));
assert_eq!(Position::Aux22, Position::from(capi::pa_channel_position_t::Aux22));
assert_eq!(Position::Aux23, Position::from(capi::pa_channel_position_t::Aux23));
assert_eq!(Position::Aux24, Position::from(capi::pa_channel_position_t::Aux24));
assert_eq!(Position::Aux25, Position::from(capi::pa_channel_position_t::Aux25));
assert_eq!(Position::Aux26, Position::from(capi::pa_channel_position_t::Aux26));
assert_eq!(Position::Aux27, Position::from(capi::pa_channel_position_t::Aux27));
assert_eq!(Position::Aux28, Position::from(capi::pa_channel_position_t::Aux28));
assert_eq!(Position::Aux29, Position::from(capi::pa_channel_position_t::Aux29));
assert_eq!(Position::Aux30, Position::from(capi::pa_channel_position_t::Aux30));
assert_eq!(Position::Aux31, Position::from(capi::pa_channel_position_t::Aux31));
assert_eq!(Position::TopCenter, Position::from(capi::pa_channel_position_t::TopCenter));
assert_eq!(Position::TopFrontLeft, Position::from(capi::pa_channel_position_t::TopFrontLeft));
assert_eq!(Position::TopFrontRight, Position::from(capi::pa_channel_position_t::TopFrontRight));
assert_eq!(Position::TopFrontCenter, Position::from(capi::pa_channel_position_t::TopFrontCenter));
assert_eq!(Position::TopRearLeft, Position::from(capi::pa_channel_position_t::TopRearLeft));
assert_eq!(Position::TopRearRight, Position::from(capi::pa_channel_position_t::TopRearRight));
assert_eq!(Position::TopRearCenter, Position::from(capi::pa_channel_position_t::TopRearCenter));
}
impl From<Position> for capi::pa_channel_position_t {
#[inline]
fn from(p: Position) -> Self {
unsafe { std::mem::transmute(p) }
}
}
impl From<capi::pa_channel_position_t> for Position {
#[inline]
fn from(p: capi::pa_channel_position_t) -> Self {
unsafe { std::mem::transmute(p) }
}
}
/// A channel map which can be used to attach labels to specific channels of a stream.
///
/// These values are relevant for conversion and mixing of streams.
#[repr(C)]
#[derive(Debug, Copy, Clone)]
pub struct Map {
/* NOTE: This struct must be directly usable by the C API, thus same attributes/layout/etc */
/// Number of channels mapped.
channels: u8,
/// Channel labels.
map: [Position; Self::CHANNELS_MAX as usize],
}
impl Borrow<[Position]> for Map {
fn borrow(&self) -> &[Position] {
&self.map[..self.channels as usize]
}
}
impl BorrowMut<[Position]> for Map {
fn borrow_mut(&mut self) -> &mut [Position] {
&mut self.map[..self.channels as usize]
}
}
/// Test size is equal to `sys` equivalent
#[test]
fn map_compare_capi() {
assert_eq!(std::mem::size_of::<Map>(), std::mem::size_of::<capi::pa_channel_map>());
assert_eq!(std::mem::align_of::<Map>(), std::mem::align_of::<capi::pa_channel_map>());
}
impl AsRef<capi::pa_channel_map> for Map {
#[inline]
fn as_ref(&self) -> &capi::pa_channel_map {
unsafe { &*(self as *const Self as *const capi::pa_channel_map) }
}
}
impl AsMut<capi::pa_channel_map> for Map {
#[inline]
fn as_mut(&mut self) -> &mut capi::pa_channel_map {
unsafe { &mut *(self as *mut Self as *mut capi::pa_channel_map) }
}
}
impl AsRef<Map> for capi::pa_channel_map {
#[inline]
fn as_ref(&self) -> &Map {
unsafe { &*(self as *const Self as *const Map) }
}
}
impl From<capi::pa_channel_map> for Map {
#[inline]
fn from(m: capi::pa_channel_map) -> Self {
unsafe { std::mem::transmute(m) }
}
}
impl Default for Map {
fn default() -> Self {
Self { channels: 0, map: [Position::Invalid; Self::CHANNELS_MAX as usize] }
}
}
impl PartialEq for Map {
#[inline]
fn eq(&self, other: &Self) -> bool {
unsafe { capi::pa_channel_map_equal(self.as_ref(), other.as_ref()) == 1 }
}
}
impl Position {
/// Makes a bit mask from a channel position.
pub const fn to_mask(self) -> PositionMask {
match self {
Position::Invalid => 0,
_ => (1 as PositionMask) << (self as PositionMask),
}
}
/// Gets a text label for the specified channel position.
pub fn to_string(pos: Self) -> Option<Cow<'static, str>> {
let ptr = unsafe { capi::pa_channel_position_to_string(pos.into()) };
match ptr.is_null() {
false => Some(unsafe { CStr::from_ptr(ptr).to_string_lossy() }),
true => None,
}
}
/// Gets a human readable text label for the specified channel position.
pub fn to_pretty_string(pos: Self) -> Option<String> {
let ptr = unsafe { capi::pa_channel_position_to_pretty_string(pos.into()) };
match ptr.is_null() {
false => Some(unsafe { CStr::from_ptr(ptr).to_string_lossy().into_owned() }),
true => None,
}
}
/// Creates a new instance from a string representation, as given by
/// [`to_string()`](Self::to_string).
pub fn from_string(s: &str) -> Self {
// Warning: New CStrings will be immediately freed if not bound to a variable, leading to
// as_ptr() giving dangling pointers!
let c_str = CString::new(s.clone()).unwrap();
unsafe { capi::pa_channel_position_from_string(c_str.as_ptr()).into() }
}
}
impl Map {
/// Maximum number of allowed channels.
pub const CHANNELS_MAX: u8 = capi::PA_CHANNELS_MAX;
/// Parses a channel position list or well-known mapping name into a channel map structure.
///
/// This turns the output of [`print()`](Self::print) and [`to_name()`](Self::to_name) back into
/// a `Map`.
pub fn new_from_string(s: &str) -> Result<Self, ()> {
// Warning: New CStrings will be immediately freed if not bound to a variable, leading to
// as_ptr() giving dangling pointers!
let c_str = CString::new(s.clone()).unwrap();
let mut map: Self = Self::default();
unsafe {
if capi::pa_channel_map_parse((&mut map).as_mut(), c_str.as_ptr()).is_null() {
return Err(());
}
}
Ok(map)
}
/// Initializes the specified channel map and returns a pointer to it.
///
/// The map will have a defined state but [`is_valid()`](Self::is_valid) will fail for it.
#[inline]
pub fn init(&mut self) -> &mut Self {
unsafe { capi::pa_channel_map_init(self.as_mut()) };
self
}
/// Initializes the specified channel map for monaural audio and returns a pointer to it.
#[inline]
pub fn init_mono(&mut self) -> &mut Self {
unsafe { capi::pa_channel_map_init_mono(self.as_mut()) };
self
}
/// Initializes the specified channel map for stereophonic audio and returns a pointer to it.
#[inline]
pub fn init_stereo(&mut self) -> &mut Self {
unsafe { capi::pa_channel_map_init_stereo(self.as_mut()) };
self
}
/// Initializes the specified channel map for the specified number of channels using default
/// labels and returns a pointer to it.
///
/// This call will fail (return `None`) if there is no default channel map known for this
/// specific number of channels and mapping.
pub fn init_auto(&mut self, channels: u8, def: MapDef) -> Option<&mut Self> {
debug_assert!(channels <= Self::CHANNELS_MAX);
unsafe {
if capi::pa_channel_map_init_auto(self.as_mut(), channels as u32, def).is_null() {
return None;
}
}
Some(self)
}
/// Similar to [`init_auto()`](Self::init_auto) but instead of failing if no default mapping is
/// known with the specified parameters it will synthesize a mapping based on a known mapping
/// with fewer channels and fill up the rest with AUX0...AUX31 channels.
pub fn init_extend(&mut self, channels: u8, def: MapDef) -> &mut Self {
debug_assert!(channels <= Self::CHANNELS_MAX);
unsafe { capi::pa_channel_map_init_extend(self.as_mut(), channels as u32, def) };
self
}
/// Checks whether or not the map is considered valid.
#[inline]
pub fn is_valid(&self) -> bool {
unsafe { capi::pa_channel_map_valid(self.as_ref()) != 0 }
}
/// Gets the number of active channels.
#[inline]
pub const fn len(&self) -> u8 {
self.channels
}
/// Sets the number of active channels.
///
/// Positions for up to [`Self::CHANNELS_MAX`] channels can be held. This sets the portion of
/// the internal array considered “active” and thus available for reading/writing (i.e. when
/// borrowing `self` as a slice).
///
/// **Panics** if the number of channels specified is greater than [`Self::CHANNELS_MAX`].
#[inline]
pub fn set_len(&mut self, channels: u8) {
assert!(channels <= Self::CHANNELS_MAX);
self.channels = channels;
}
/// Gets an immutable slice of the set of “active” channels.
#[inline]
pub fn get(&self) -> &[Position] {
self.borrow()
}
/// Gets a mutable slice of the set of “active” channels.
#[inline]
pub fn get_mut(&mut self) -> &mut [Position] {
self.borrow_mut()
}
/// Makes a human readable string from the map.
pub fn print(&self) -> String {
const PRINT_MAX: usize = capi::PA_CHANNEL_MAP_SNPRINT_MAX;
let mut tmp = Vec::with_capacity(PRINT_MAX);
unsafe {
capi::pa_channel_map_snprint(tmp.as_mut_ptr(), PRINT_MAX, self.as_ref());
CStr::from_ptr(tmp.as_mut_ptr()).to_string_lossy().into_owned()
}
}
/// Checks whether or not the specified map is compatible with the specified sample spec.
#[inline]
pub fn is_compatible_with_sample_spec(&self, ss: &sample::Spec) -> bool {
unsafe { capi::pa_channel_map_compatible(self.as_ref(), ss.as_ref()) != 0 }
}
/// Checks whether every channel defined in `of` is also defined in self.
#[inline]
pub fn is_superset_of(&self, of: &Self) -> bool {
unsafe { capi::pa_channel_map_superset(self.as_ref(), of.as_ref()) != 0 }
}
/// Checks whether or not it makes sense to apply a volume “balance” with this mapping, i.e. if
/// there are left/right channels available.
#[inline]
pub fn can_balance(&self) -> bool {
unsafe { capi::pa_channel_map_can_balance(self.as_ref()) != 0 }
}
/// Checks whether or not it makes sense to apply a volume “fade” (i.e. “balance” between front
/// and rear) with this mapping, i.e. if there are front/rear channels available.
#[inline]
pub fn can_fade(&self) -> bool {
unsafe { capi::pa_channel_map_can_fade(self.as_ref()) != 0 }
}
/// Checks whether or not it makes sense to apply a volume “LFE balance” (i.e. “balance” between
/// LFE and non-LFE channels) with this mapping, i.e. if there are LFE and non-LFE channels
/// available.
#[inline]
#[cfg(any(doc, feature = "pa_v8"))]
#[cfg_attr(docsrs, doc(cfg(feature = "pa_v8")))]
pub fn can_lfe_balance(&self) -> bool {
unsafe { capi::pa_channel_map_can_lfe_balance(self.as_ref()) != 0 }
}
/// Tries to find a well-known channel mapping name for this channel mapping, i.e. “stereo”,
/// “surround-71” and so on. This name can be parsed with
/// [`new_from_string()`](Self::new_from_string).
pub fn to_name(&self) -> Option<Cow<'static, str>> {
let ptr = unsafe { capi::pa_channel_map_to_name(self.as_ref()) };
match ptr.is_null() {
false => Some(unsafe { CStr::from_ptr(ptr).to_string_lossy() }),
true => None,
}
}
/// Similar to [`to_name()`](Self::to_name), but returning prettier, human readable text labels,
/// i.e. “Stereo”, “Surround 7.1” and so on.
pub fn to_pretty_name(&self) -> Option<String> {
let ptr = unsafe { capi::pa_channel_map_to_pretty_name(self.as_ref()) };
match ptr.is_null() {
false => Some(unsafe { CStr::from_ptr(ptr).to_string_lossy().into_owned() }),
true => None,
}
}
/// Checks whether or not the specified channel position is available at least once in the map.
#[inline]
pub fn has_position(&self, p: Position) -> bool {
unsafe { capi::pa_channel_map_has_position(self.as_ref(), p.into()) != 0 }
}
/// Generates a bit mask from a map.
#[inline]
pub fn get_mask(&self) -> PositionMask {
unsafe { capi::pa_channel_map_mask(self.as_ref()) }
}
}