1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145

// Augmented Audio: Audio libraries and applications
// Copyright (c) 2022 Pedro Tacla Yamada
//
// The MIT License (MIT)
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//! Provides a basic mechanism for defining float parameters and modifying them
//! through introspection at runtime.

use std::convert::TryFrom;

use audio_garbage_collector::{make_shared, Shared};

/// A shared reference to a boxed generic handle
pub type AudioProcessorHandleRef = Shared<Box<dyn AudioProcessorHandle>>;

/// Build a shared reference to a boxed generic handle
pub fn make_handle_ref<T: AudioProcessorHandle + 'static>(v: T) -> AudioProcessorHandleRef {
    make_shared(Box::new(v))
}

/// A type which can create an `AudioProcessorHandleRef`
pub trait AudioProcessorHandleProvider {
    fn generic_handle(&self) -> AudioProcessorHandleRef;
}

/// An empty handle with no parameters
pub struct AudioProcessorEmptyHandle;

impl AudioProcessorHandle for AudioProcessorEmptyHandle {
    fn parameter_count(&self) -> usize {
        0
    }

    fn get_parameter_spec(&self, _index: usize) -> ParameterSpec {
        panic!("There are no parameter specs")
    }

    fn get_parameter(&self, _index: usize) -> Option<ParameterValue> {
        None
    }

    fn set_parameter(&self, _index: usize, _request: ParameterValue) {}
}

/// This trait can be implemented by AudioProcessor handles to provide runtime introspection on
/// the parameters that a processor provides.
pub trait AudioProcessorHandle: Send + Sync {
    /// This method should return the name of the processor. This may displayed in a GUI application
    /// as the effect/instrument name.
    fn name(&self) -> String {
        "AudioProcessorHandle::name can be set at the processor handle with a name for the handle"
            .to_string()
    }

    /// Should return the number of parameters.
    fn parameter_count(&self) -> usize;

    /// After finding the number of parameters a callee will get `ParameterSpec` declarations
    /// giving more metadata about this parameter.
    fn get_parameter_spec(&self, index: usize) -> ParameterSpec;

    /// Should return the value for the parameter at this index
    fn get_parameter(&self, index: usize) -> Option<ParameterValue>;

    /// Should set the value for the parameter at this index
    fn set_parameter(&self, index: usize, request: ParameterValue);
}

/// A runtime typed parameter value
#[derive(PartialEq, Clone, Debug)]
pub enum ParameterValue {
    Float { value: f32 },
}

impl From<f32> for ParameterValue {
    fn from(value: f32) -> Self {
        Self::Float { value }
    }
}

impl TryFrom<ParameterValue> for f32 {
    type Error = ();

    fn try_from(value: ParameterValue) -> Result<Self, Self::Error> {
        let ParameterValue::Float { value } = value;
        Ok(value)
    }
}

#[derive(Debug, Clone)]
pub struct FloatType {
    pub range: (f32, f32),
    pub step: Option<f32>,
}

#[derive(Debug, Clone)]
pub enum ParameterType {
    Float(FloatType),
}

impl ParameterType {
    pub fn float(&self) -> Option<&FloatType> {
        let ParameterType::Float(inner) = self;
        Some(inner)
    }
}

/// Meta-data around a parameter. A GUI application may use this information to display
/// the label around the parameter and decide what type of control to render to modify it.
#[derive(Debug, Clone)]
pub struct ParameterSpec {
    name: String,
    ty: ParameterType,
}

impl ParameterSpec {
    pub fn new(name: String, ty: ParameterType) -> Self {
        ParameterSpec { name, ty }
    }

    pub fn name(&self) -> &str {
        &self.name
    }

    pub fn ty(&self) -> &ParameterType {
        &self.ty
    }
}