From c93ffcff6c84eeaae88407a5c5840f1c104b66c8 Mon Sep 17 00:00:00 2001
From: Pierre Krieger <pierre.krieger1708@gmail.com>
Date: Sun, 27 Sep 2015 13:00:17 +0200
Subject: [PATCH] Add Voice::get_period()

---
 Cargo.toml          |  2 +-
 src/alsa/mod.rs     | 21 +++++++++++++++------
 src/lib.rs          | 10 ++++++++++
 src/null/mod.rs     |  5 +++++
 src/wasapi/voice.rs |  5 +++++
 5 files changed, 36 insertions(+), 7 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index e7e12e6..27830ce 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 
 name = "cpal"
-version = "0.2.5"
+version = "0.2.6"
 authors = ["Pierre Krieger <pierre.krieger1708@gmail.com>"]
 description = "Cross-platform audio playing library in pure Rust."
 repository = "https://github.com/tomaka/cpal"
diff --git a/src/alsa/mod.rs b/src/alsa/mod.rs
index dd1b8a5..dca18df 100644
--- a/src/alsa/mod.rs
+++ b/src/alsa/mod.rs
@@ -174,6 +174,7 @@ pub struct Voice {
     channel: Mutex<*mut alsa::snd_pcm_t>,
     num_channels: u16,
     buffer_len: usize,      // number of samples that can fit in the buffer
+    period_len: usize,      // minimum number of samples to put in the buffer
 }
 
 pub struct Buffer<'a, T> {
@@ -232,18 +233,21 @@ impl Voice {
 
             check_errors(alsa::snd_pcm_prepare(playback_handle)).unwrap();
 
-            let buffer_len = {
-                let mut dummy = mem::uninitialized();
-                let mut val = mem::uninitialized();
-                check_errors(alsa::snd_pcm_get_params(playback_handle, &mut val, &mut dummy)).unwrap();
-                assert!(val != 0);
-                val as usize * format.channels.len()
+            let (buffer_len, period_len) = {
+                let mut buffer = mem::uninitialized();
+                let mut period = mem::uninitialized();
+                check_errors(alsa::snd_pcm_get_params(playback_handle, &mut buffer, &mut period)).unwrap();
+                assert!(buffer != 0);
+                let buffer = buffer as usize * format.channels.len();
+                let period = period as usize * format.channels.len();
+                (buffer, period)
             };
 
             Ok(Voice {
                 channel: Mutex::new(playback_handle),
                 num_channels: format.channels.len() as u16,
                 buffer_len: buffer_len,
+                period_len: period_len,
             })
         }
     }
@@ -283,6 +287,11 @@ impl Voice {
         unimplemented!()
     }
 
+    #[inline]
+    pub fn get_period(&self) -> usize {
+        self.period_len
+    }
+
     pub fn get_pending_samples(&self) -> usize {
         let available = {
             let channel = self.channel.lock().unwrap();
diff --git a/src/lib.rs b/src/lib.rs
index df40aff..2bfd356 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -324,6 +324,16 @@ impl Voice {
         self.format().data_type
     }
 
+    /// Returns the minimum number of samples that should be put in a buffer before it is
+    /// processable by the audio output.
+    ///
+    /// If you put less than this value in the buffer, the buffer will not be processed and you
+    /// risk an underrun.
+    #[inline]
+    pub fn get_period(&self) -> usize {
+        self.voice.get_period()
+    }
+
     /// Adds some PCM data to the voice's buffer.
     ///
     /// This function indirectly returns a `Buffer` object that must be filled with the audio data.
diff --git a/src/null/mod.rs b/src/null/mod.rs
index 0021a18..c8f6d37 100644
--- a/src/null/mod.rs
+++ b/src/null/mod.rs
@@ -72,6 +72,11 @@ impl Voice {
     pub fn pause(&mut self) {
     }
 
+    #[inline]
+    pub fn get_period(&self) -> usize {
+        0
+    }
+
     #[inline]
     pub fn get_pending_samples(&self) -> usize {
         unreachable!()
diff --git a/src/wasapi/voice.rs b/src/wasapi/voice.rs
index 802d4d2..bcadf47 100644
--- a/src/wasapi/voice.rs
+++ b/src/wasapi/voice.rs
@@ -193,6 +193,11 @@ impl Voice {
         }
     }
 
+    #[inline]
+    pub fn get_period(&self) -> usize {
+        0
+    }
+
     pub fn get_pending_samples(&self) -> usize {
         unsafe {
             let mut padding = mem::uninitialized();