Refactoring: add copy_raw_audio()
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@ -41,8 +41,6 @@ pub fn extract_nrg_raw_audio(in_fd: &mut File,
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img_path: &String,
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metadata: &NrgMetadata)
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-> Result<(), NrgError> {
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const BUF_SIZE: usize = 1024 * 1024 * 4; // 4 MiB
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// Seek to the first audio byte
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let first_audio_byte = metadata.first_audio_byte();
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try!(in_fd.seek(SeekFrom::Start(first_audio_byte)));
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@ -54,16 +52,37 @@ pub fn extract_nrg_raw_audio(in_fd: &mut File,
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let audio_name = try!(make_output_file_name(img_path));
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let mut out_fd = try!(File::create(audio_name));
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// Copy the audio data
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let count = last_audio_byte - first_audio_byte;
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let bytes_copied = try!(copy_raw_audio(in_fd, &mut out_fd, count));
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assert_eq!(count, bytes_copied);
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Ok(())
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}
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/// Reads `count` bytes from `in_fd` and write them to `out_fd`.
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///
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/// The offsets of `in_fd` and `out_fd` are not reset prior to reading and
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/// writing.
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///
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/// Returns the number of bytes copied.
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fn copy_raw_audio(in_fd: &mut File, out_fd: &mut File, count: u64)
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-> Result<u64, NrgError> {
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// The buffer size (~4,6 MiB) is a multiple of the standard audio CD sector
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// size, i.e. 2352 bytes (it doesn't have to be, though).
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const BUF_SIZE: usize = 2352 * 1024 * 2;
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// Read/write audio data
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let mut cur_offset = first_audio_byte;
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while cur_offset + BUF_SIZE as u64 <= last_audio_byte {
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let mut bytes_read = 0;
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while bytes_read + BUF_SIZE as u64 <= count {
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let mut audio_buf = [0u8; BUF_SIZE];
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let mut nbytes = try!(in_fd.read(&mut audio_buf));
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if nbytes != BUF_SIZE {
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return Err(NrgError::AudioReadError);
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}
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cur_offset += nbytes as u64;
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bytes_read += nbytes as u64;
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nbytes = try!(out_fd.write(&audio_buf));
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if nbytes != BUF_SIZE {
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@ -72,20 +91,19 @@ pub fn extract_nrg_raw_audio(in_fd: &mut File,
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}
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// Read/write the last bytes
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let remaining: usize = (last_audio_byte - cur_offset) as usize;
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let remaining: usize = (count - bytes_read) as usize;
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let mut audio_buf = vec![0u8; remaining];
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let mut nbytes = try!(in_fd.read(&mut audio_buf));
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if nbytes != remaining {
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return Err(NrgError::AudioReadError);
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}
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cur_offset += nbytes as u64;
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bytes_read += nbytes as u64;
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nbytes = try!(out_fd.write(&audio_buf));
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if nbytes != remaining {
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return Err(NrgError::AudioWriteError);
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}
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assert_eq!(cur_offset, last_audio_byte);
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Ok(())
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Ok(bytes_read)
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}
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