Writer implementation

creaet_frame_buffer() interface has been moved to WaveFmt

src/audio_frame_reader.rs

@@ -62,13 +62,6 @@ impl<R: Read + Seek> AudioFrameReader<R> {
         Ok( (seek_result - self.start) / self.format.block_alignment as u64 )
     }
 
-    /// Create a frame buffer sized to hold frames of the reader
-    /// 
-    /// This is a conveneince method that creates a `Vec<i32>` with
-    /// as many elements as there are channels in the underlying stream. 
-    pub fn create_frame_buffer(&self) -> Vec<i32> {
-        vec![0i32; self.format.channel_count as usize]
-    }
 
     /// Read a frame
     /// 

src/audio_frame_writer.rs

@@ -0,0 +1,46 @@
+use std::io::{Write,Seek};
+
+use super::wavewriter::WaveWriter;
+use super::errors::Error;
+use super::fmt::WaveFmt;
+
+use byteorder::LittleEndian;
+use byteorder::WriteBytesExt;
+
+pub struct AudioFrameWriter<W: Write + Seek> {
+    inner : W,
+    form_size : u64,
+    data_size : u64,
+    format: WaveFmt
+}
+
+impl<W: Write + Seek> AudioFrameWriter<W> {
+    pub fn make(wave_writer : WaveWriter<W>) -> Self {
+        Self { 
+            inner: wave_writer.inner, 
+            form_size: wave_writer.form_size,
+            data_size: 0u64,
+            format : wave_writer.format
+        }
+    }
+
+    pub fn write_integer_frame(&mut self, buffer: &mut [i32]) -> Result<u64, Error> {
+        assert!(buffer.len() as u16 == self.format.channel_count, 
+            "write_integer_frame was called with a mis-sized buffer, expected {}, was {}", 
+            self.format.channel_count, buffer.len());
+
+            let framed_bits_per_sample = self.format.block_alignment * 8 / self.format.channel_count;
+
+            for n in 0..(self.format.channel_count as usize) {
+                match (self.format.bits_per_sample, framed_bits_per_sample) {
+                    (0..=8,8) => self.inner.write_u8(buffer[n] as u8 + 0x80_u8)?, // EBU 3285 §A2.2
+                    (9..=16,16) => self.inner.write_i16::<LittleEndian>(buffer[n] as i16)?,
+                    (10..=24,24) => self.inner.write_i24::<LittleEndian>(buffer[n])?,
+                    (25..=32,32) => self.inner.write_i32::<LittleEndian>(buffer[n])?,
+                    (b,_)=> panic!("Unrecognized integer format, bits per sample {}, channels {}, block_alignment {}", 
+                        b, self.format.channel_count, self.format.block_alignment)
+                }
+            }
+            Ok( 1 )
+    }
+}

src/fmt.rs

@@ -212,6 +212,15 @@ impl WaveFmt {
         CommonFormat::make( self.tag, self.extended_format.map(|ext| ext.type_guid))
     }
 
+    /// Create a frame buffer sized to hold frames for a reader or writer
+    /// 
+    /// This is a conveneince method that creates a `Vec<i32>` with
+    /// as many elements as there are channels in the underlying stream. 
+    pub fn create_frame_buffer(&self) -> Vec<i32> {
+        vec![0i32; self.channel_count as usize]
+    }
+
+
     /// Channel descriptors for each channel.
     pub fn channels(&self) -> Vec<ChannelDescriptor> {
         match self.channel_count {

src/lib.rs

@@ -112,6 +112,7 @@ mod common_format;
 mod parser;
 
 mod audio_frame_reader;
+mod audio_frame_writer;
 mod list_form;
 
 mod chunks;

src/wavereader.rs

@@ -28,7 +28,7 @@ use std::io::{Read, Seek};
  * assert_eq!(format.channel_count, 1);
  * 
  * let mut frame_reader = r.audio_frame_reader().unwrap();
- * let mut buffer = frame_reader.create_frame_buffer();
+ * let mut buffer = format.create_frame_buffer();
  * 
  * let read = frame_reader.read_integer_frame(&mut buffer).unwrap();
  * 

src/wavewriter.rs

@@ -4,17 +4,18 @@ use std::io::Cursor;
 
 use super::errors::Error;
 use super::chunks::{WriteBWaveChunks};
-use super::bext::Bext;
 use super::fmt::{WaveFmt};
-use super::fourcc::{FourCC, RIFF_SIG, WAVE_SIG, FMT__SIG, JUNK_SIG, BEXT_SIG, DATA_SIG, WriteFourCC};
+use super::fourcc::{FourCC, RIFF_SIG, WAVE_SIG, FMT__SIG, JUNK_SIG, BEXT_SIG, DATA_SIG, FLLR_SIG, WriteFourCC};
+use super::audio_frame_writer::AudioFrameWriter;
 
 use byteorder::LittleEndian;
 use byteorder::WriteBytesExt;
 
 /// This isn't working yet, do not use.
 pub struct WaveWriter<W> where W: Write + Seek {
-    inner : W,
-    form_size : u64
+    pub inner : W,
+    pub form_size : u64,
+    pub format : WaveFmt
 }
 
 impl WaveWriter<File> {
@@ -27,7 +28,7 @@ impl WaveWriter<File> {
 impl<W: Write + Seek> WaveWriter<W> {
     /// Wrap a `Write` struct with a wavewriter.
     fn new(inner : W, format: WaveFmt) -> Result<Self,Error> {
-        let mut retval = Self { inner, form_size : 0 };
+        let mut retval = Self { inner, form_size : 0 , format: format};
         retval.inner.seek(SeekFrom::Start(0))?;
         retval.inner.write_fourcc(RIFF_SIG)?;
         retval.inner.write_u32::<LittleEndian>(0)?;
@@ -43,6 +44,30 @@ impl<W: Write + Seek> WaveWriter<W> {
         return self.inner;
     }
 
+    /// Return an AudioFrameWriter, consuming the reader.
+    fn audio_frame_writer(mut self) -> Result<AudioFrameWriter<W>, Error> {
+
+        let framing = 0x4000;
+        self.append_data_framing_chunk(framing)?;
+
+        self.inner.write_fourcc(DATA_SIG)?;
+        self.inner.write_u32::<LittleEndian>(0u32)?;
+        self.update_form_size(8)?;
+
+        Ok( AudioFrameWriter::make(self) )
+    }
+
+    fn append_data_framing_chunk(&mut self, framing: u64) -> Result<(), Error> {
+        let current_length = self.inner.seek(SeekFrom::End(0))?;
+        let size_to_add = (current_length % framing) - 8;
+        let chunk_size_to_add = size_to_add - 8;
+
+        let buf = vec![ 0u8; chunk_size_to_add as usize];
+        self.append_chunk(FLLR_SIG, &buf)?;
+
+        Ok( () )
+    }
+
     /// Append data as a new chunk to the wave file.
     fn append_chunk(&mut self, ident: FourCC, data: &[u8]) -> Result<(),Error> {
         assert!(data.len() < (u32::MAX as usize),