Writer implementation

creaet_frame_buffer() interface has been moved to WaveFmt

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 )
+    }
+}