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Refactoring: add copy_raw_audio()

master
Matteo Cypriani 4 years ago
parent
commit
6ee363064b
1 changed files with 27 additions and 9 deletions
  1. +27
    -9
      src/raw_audio.rs

+ 27
- 9
src/raw_audio.rs View File

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


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