gstreamer-audio: Add AudioCapsBuilder

gstreamer-audio/src/caps.rs

@@ -0,0 +1,140 @@
+use crate::{AudioFormat, AudioLayout};
+use gst::prelude::*;
+use gst::Caps;
+use std::ops::Bound::*;
+use std::ops::RangeBounds;
+
+pub struct AudioCapsBuilder<T> {
+    builder: gst::caps::Builder<T>,
+}
+
+impl AudioCapsBuilder<gst::caps::NoFeature> {
+    pub fn new() -> Self {
+        let builder = Caps::builder("audio/x-raw");
+        AudioCapsBuilder { builder }
+    }
+
+    pub fn any_features(self) -> AudioCapsBuilder<gst::caps::HasFeatures> {
+        AudioCapsBuilder {
+            builder: self.builder.any_features(),
+        }
+    }
+
+    pub fn features(self, features: &[&str]) -> AudioCapsBuilder<gst::caps::HasFeatures> {
+        AudioCapsBuilder {
+            builder: self.builder.features(features),
+        }
+    }
+}
+
+impl Default for AudioCapsBuilder<gst::caps::NoFeature> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl<T> AudioCapsBuilder<T> {
+    pub fn format(self, format: AudioFormat) -> Self {
+        Self {
+            builder: self.builder.field("format", format.to_str()),
+        }
+    }
+
+    pub fn format_list(self, formats: impl IntoIterator<Item = AudioFormat>) -> Self {
+        Self {
+            builder: self.builder.field(
+                "format",
+                gst::List::new(formats.into_iter().map(|f| f.to_str())),
+            ),
+        }
+    }
+
+    pub fn rate(self, rate: i32) -> Self {
+        Self {
+            builder: self.builder.field("rate", rate),
+        }
+    }
+
+    pub fn rate_range(self, rates: impl RangeBounds<i32>) -> Self {
+        let (start, end) = range_bounds_i32_start_end(rates);
+        let gst_rates = gst::IntRange::<i32>::new(start, end);
+        Self {
+            builder: self.builder.field("rate", gst_rates),
+        }
+    }
+
+    pub fn rate_list(self, rates: impl IntoIterator<Item = i32>) -> Self {
+        Self {
+            builder: self.builder.field("rate", gst::List::new(rates)),
+        }
+    }
+
+    pub fn channels(self, channels: i32) -> Self {
+        Self {
+            builder: self.builder.field("channels", channels),
+        }
+    }
+
+    pub fn channels_range(self, channels: impl RangeBounds<i32>) -> Self {
+        let (start, end) = range_bounds_i32_start_end(channels);
+        let gst_channels: gst::IntRange<i32> = gst::IntRange::new(start, end);
+        Self {
+            builder: self.builder.field("channels", gst_channels),
+        }
+    }
+
+    pub fn channels_list(self, channels: impl IntoIterator<Item = i32>) -> Self {
+        Self {
+            builder: self.builder.field("channels", gst::List::new(channels)),
+        }
+    }
+
+    pub fn layout(self, layout: AudioLayout) -> Self {
+        Self {
+            builder: self.builder.field("layout", layout_str(layout)),
+        }
+    }
+
+    pub fn layout_list(self, layouts: impl IntoIterator<Item = AudioLayout>) -> Self {
+        Self {
+            builder: self.builder.field(
+                "layout",
+                gst::List::new(layouts.into_iter().map(layout_str)),
+            ),
+        }
+    }
+
+    pub fn field<V: ToSendValue + Sync>(self, name: &str, value: V) -> Self {
+        Self {
+            builder: self.builder.field(name, value),
+        }
+    }
+
+    pub fn build(self) -> gst::Caps {
+        self.builder.build()
+    }
+}
+
+fn range_bounds_i32_start_end(range: impl RangeBounds<i32>) -> (i32, i32) {
+    skip_assert_initialized!();
+    let start = match range.start_bound() {
+        Unbounded => 1,
+        Excluded(n) => n + 1,
+        Included(n) => *n,
+    };
+    let end = match range.end_bound() {
+        Unbounded => i32::MAX,
+        Excluded(n) => n - 1,
+        Included(n) => *n,
+    };
+    (start, end)
+}
+
+fn layout_str(layout: AudioLayout) -> &'static str {
+    skip_assert_initialized!();
+    match layout {
+        crate::AudioLayout::Interleaved => "interleaved",
+        crate::AudioLayout::NonInterleaved => "non-interleaved",
+        crate::AudioLayout::__Unknown(_) => "unknown",
+    }
+}

gstreamer-audio/src/lib.rs

@@ -36,6 +36,9 @@ macro_rules! skip_assert_initialized {
 mod auto;
 pub use crate::auto::*;
 
+mod caps;
+pub use crate::caps::AudioCapsBuilder;
+
 #[cfg(feature = "ser_de")]
 mod flag_serde;