78 lines
2.3 KiB
Rust
78 lines
2.3 KiB
Rust
//! Module to extract the raw audio data from an NRG image file.
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use std::fs::File;
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use std::io::{Seek, SeekFrom, Read, Write};
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use ::error::NrgError;
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use ::metadata::metadata::NrgMetadata;
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/// Extracts the raw audio data from an NRG image.
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///
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/// - `in_fd` is the handler to the NRG image file.
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/// - `image_name` is the name of the input NRG file.
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/// - `metadata` is the metadata extracted from `image_name` by
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/// nrgrip::metadata.
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///
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/// The output file's name is derived from `image_name`.
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pub fn extract_nrg_raw_audio(in_fd: &mut File,
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image_name: &String,
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metadata: &NrgMetadata)
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-> Result<(), NrgError> {
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let skip_bytes = get_daox_track1_index1(metadata);
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try!(in_fd.seek(SeekFrom::Start(skip_bytes)));
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let file_name = make_output_file_name(image_name);
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let mut out_fd = try!(File::create(file_name));
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let mut cur_offset = skip_bytes;
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while cur_offset < metadata.chunk_offset {
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let mut audio_buf = [0u8; 2352];
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let mut nbytes = try!(in_fd.read(&mut audio_buf));
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if nbytes != 2352 {
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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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nbytes = try!(out_fd.write(&audio_buf));
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if nbytes != 2352 {
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return Err(NrgError::AudioWriteError);
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}
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}
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assert_eq!(cur_offset, metadata.chunk_offset);
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Ok(())
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}
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/// Returns the index1 of the first DAOX track in `metadata`, or 0 if there are
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/// no DAOX tracks.
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fn get_daox_track1_index1(metadata: &NrgMetadata) -> u64 {
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if metadata.daox_chunk.is_none() {
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return 0;
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}
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let daox_tracks = &metadata.daox_chunk.as_ref().unwrap().tracks;
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if daox_tracks.is_empty() {
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return 0;
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}
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return daox_tracks[0].index1;
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}
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/// Generates the output file's name from the NRG image's name.
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///
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/// If `image_name`'s extension is `.nrg` (case-insensitive), the name will be
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/// the same as `image_name` with a `.raw` extension instead of `.nrg`.
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/// Otherwise, it will be `image_name.raw`.
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fn make_output_file_name(image_name: &String) -> String {
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let mut name = image_name.clone();
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if name.to_lowercase().ends_with(".nrg") {
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let newlen = name.len() - 4;
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name.truncate(newlen);
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}
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name.push_str(".raw");
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name
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}
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