From 2e7495162841e9038b47622ba745e8830db4a2f8 Mon Sep 17 00:00:00 2001
From: Matteo Cypriani <mcy@lm7.fr>
Date: Tue, 6 Dec 2016 21:10:38 -0500
Subject: [PATCH] Audio data extraction

---
 src/cue_sheet/mod.rs |  5 ++-
 src/error.rs         |  8 +++++
 src/lib.rs           |  1 +
 src/main.rs          |  9 ++++++
 src/raw_audio.rs     | 77 ++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 99 insertions(+), 1 deletion(-)
 create mode 100644 src/raw_audio.rs

diff --git a/src/cue_sheet/mod.rs b/src/cue_sheet/mod.rs
index 25c3dc3..7a0091b 100644
--- a/src/cue_sheet/mod.rs
+++ b/src/cue_sheet/mod.rs
@@ -10,7 +10,10 @@ use ::metadata::cuex::NrgCuexTrack;
 
 /// Writes the cue sheet for `image_name` into a file.
 ///
-/// `metadata` is the metadata extracted from `image_name` by nrgrip::metadata.
+/// - `image_name` is the name of the input NRG file.
+/// - `metadata` is the metadata extracted from `image_name` by
+///    nrgrip::metadata.
+///
 /// The output file's name is derived from `image_name`.
 pub fn write_cue_sheet(image_name: &String, metadata: &NrgMetadata)
                        -> Result<(), NrgError> {
diff --git a/src/error.rs b/src/error.rs
index c16ac81..d2a51fc 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -12,6 +12,8 @@ pub enum NrgError {
     NrgFormatV1,
     NrgChunkId,
     NoNrgCue,
+    AudioReadError,
+    AudioWriteError
 }
 
 impl fmt::Display for NrgError {
@@ -22,6 +24,8 @@ impl fmt::Display for NrgError {
             NrgError::NrgFormatV1 => write!(f, "NRG v1 format is not handled."),
             NrgError::NrgChunkId => write!(f, "NRG chunk ID unknown."),
             NrgError::NoNrgCue => write!(f, "NRG cue sheet chunk absent."),
+            NrgError::AudioReadError => write!(f, "Error reading raw audio."),
+            NrgError::AudioWriteError => write!(f, "Error writing raw audio."),
         }
     }
 }
@@ -34,6 +38,8 @@ impl Error for NrgError {
             NrgError::NrgFormatV1 => "NRG format v1",
             NrgError::NrgChunkId => "NRG chunk ID",
             NrgError::NoNrgCue => "No NRG cue",
+            NrgError::AudioReadError => "Audio read error",
+            NrgError::AudioWriteError => "Audio write error",
         }
     }
 
@@ -44,6 +50,8 @@ impl Error for NrgError {
             NrgError::NrgFormatV1 => None,
             NrgError::NrgChunkId => None,
             NrgError::NoNrgCue => None,
+            NrgError::AudioReadError => None,
+            NrgError::AudioWriteError => None,
         }
     }
 }
diff --git a/src/lib.rs b/src/lib.rs
index b19f5a1..4b8c12e 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -3,3 +3,4 @@
 pub mod error;
 pub mod metadata;
 pub mod cue_sheet;
+pub mod raw_audio;
diff --git a/src/main.rs b/src/main.rs
index f6aaf57..1652755 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -48,8 +48,17 @@ fn main() {
     println!("\n{}", metadata);
 
     // Read and write the cue sheet
+    println!("\nNow extracting cue sheet...");
     if let Err(err) = nrgrip::cue_sheet::write_cue_sheet(&img_name, &metadata) {
         println!("Error writing cue sheet: {}", err.to_string());
         process::exit(1);
     }
+
+    // Extract raw audio data
+    println!("Now extracting raw audio data...");
+    if let Err(err) = nrgrip::raw_audio::extract_nrg_raw_audio(
+        &mut fd, &img_name, &metadata) {
+        println!("Error extracting raw audio data: {}", err.to_string());
+    }
+    println!("OK!");
 }
diff --git a/src/raw_audio.rs b/src/raw_audio.rs
new file mode 100644
index 0000000..846a87d
--- /dev/null
+++ b/src/raw_audio.rs
@@ -0,0 +1,77 @@
+//! Module to extract the raw audio data from an NRG image file.
+
+use std::fs::File;
+use std::io::{Seek, SeekFrom, Read, Write};
+
+use ::error::NrgError;
+use ::metadata::metadata::NrgMetadata;
+
+
+/// Extracts the raw audio data from an NRG image.
+///
+/// - `in_fd` is the handler to the NRG image file.
+/// - `image_name` is the name of the input NRG file.
+/// - `metadata` is the metadata extracted from `image_name` by
+///    nrgrip::metadata.
+///
+/// The output file's name is derived from `image_name`.
+pub fn extract_nrg_raw_audio(in_fd: &mut File,
+                             image_name: &String,
+                             metadata: &NrgMetadata)
+                             -> Result<(), NrgError> {
+    let skip_bytes = get_daox_track1_index1(metadata);
+
+    try!(in_fd.seek(SeekFrom::Start(skip_bytes)));
+
+    let file_name = make_output_file_name(image_name);
+    let mut out_fd = try!(File::create(file_name));
+
+    let mut cur_offset = skip_bytes;
+    while cur_offset < metadata.chunk_offset {
+        let mut audio_buf = [0u8; 2352];
+
+        let mut nbytes = try!(in_fd.read(&mut audio_buf));
+        if nbytes != 2352 {
+            return Err(NrgError::AudioReadError);
+        }
+        cur_offset += nbytes as u64;
+
+        nbytes = try!(out_fd.write(&audio_buf));
+        if nbytes != 2352 {
+            return Err(NrgError::AudioWriteError);
+        }
+    }
+
+    assert_eq!(cur_offset, metadata.chunk_offset);
+    Ok(())
+}
+
+
+/// Returns the index1 of the first DAOX track in `metadata`, or 0 if there are
+/// no DAOX tracks.
+fn get_daox_track1_index1(metadata: &NrgMetadata) -> u64 {
+    if metadata.daox_chunk.is_none() {
+        return 0;
+    }
+    let daox_tracks = &metadata.daox_chunk.as_ref().unwrap().tracks;
+    if daox_tracks.is_empty() {
+        return 0;
+    }
+    return daox_tracks[0].index1;
+}
+
+
+/// Generates the output file's name from the NRG image's name.
+///
+/// If `image_name`'s extension is `.nrg` (case-insensitive), the name will be
+/// the same as `image_name` with a `.raw` extension instead of `.nrg`.
+/// Otherwise, it will be `image_name.raw`.
+fn make_output_file_name(image_name: &String) -> String {
+    let mut name = image_name.clone();
+    if name.to_lowercase().ends_with(".nrg") {
+        let newlen = name.len() - 4;
+        name.truncate(newlen);
+    }
+    name.push_str(".raw");
+    name
+}