Refactor arc parsing and add internal tests for it

src/ddr/arc.rs

@@ -1,5 +1,6 @@
 use std::collections::HashMap;
 use std::convert::TryInto;
+use std::default::Default;
 use std::io;
 use std::io::prelude::*;
 use std::io::Cursor;
@@ -7,6 +8,7 @@ use std::num;
 use std::path::PathBuf;
 
 use byteorder::{ReadBytesExt, LE};
+use derive_more::Deref;
 use konami_lz77::decompress;
 use log::{debug, info, trace, warn};
 use thiserror::Error;
@@ -29,38 +31,80 @@ pub enum Error {
     MiniParserError(#[from] mini_parser::MiniParserError),
 }
 
-#[derive(Debug)]
+type Result<T> = std::result::Result<T, Error>;
+
+#[derive(Debug, Default, PartialEq)]
 struct CueEntry {
-    name_offset: usize,
+    path_offset: usize,
     data_offset: usize,
     decompressed_size: usize,
     compressed_size: usize,
 }
 
 impl CueEntry {
-    fn parse(data: &[u8]) -> Result<Self, Error> {
+    fn parse(data: &[u8]) -> Result<Self> {
         let mut cursor = Cursor::new(data);
 
-        let name_offset = cursor.read_u32::<LE>()?.try_into()?;
+        let path_offset = cursor.read_u32::<LE>()?.try_into()?;
         let data_offset = cursor.read_u32::<LE>()?.try_into()?;
         let decompressed_size = cursor.read_u32::<LE>()?.try_into()?;
         let compressed_size = cursor.read_u32::<LE>()?.try_into()?;
 
         Ok(Self {
-            name_offset,
+            path_offset,
             data_offset,
             decompressed_size,
             compressed_size,
         })
     }
+
+    fn parse_path(&self, data: &[u8]) -> Result<PathBuf> {
+        Ok(PathBuf::from(
+            String::from_utf8_lossy(
+                &mini_parser::get_slice_range(data, self.path_offset..data.len())?
+                    .iter()
+                    .take_while(|byte| **byte != 0)
+                    .cloned()
+                    .collect::<Vec<u8>>(),
+            )
+            .into_owned(),
+        ))
+    }
 }
 
-pub struct ARC {
+#[derive(Debug, Deref, PartialEq)]
-    pub files: HashMap<PathBuf, Vec<u8>>,
+struct Cue(HashMap<PathBuf, CueEntry>);
+
+impl Cue {
+    fn parse(data: &[u8], arc_data: &[u8]) -> Result<Self> {
+        let mut cue = HashMap::new();
+
+        for chunk in data.chunks(4 * 4) {
+            let entry = CueEntry::parse(chunk)?;
+            let path = entry.parse_path(arc_data)?;
+            trace!(
+                "Found cue entry with path {} at {} (size {})",
+                path.display(),
+                entry.data_offset,
+                entry.decompressed_size,
+            );
+            cue.insert(path, entry);
         }
 
-impl ARC {
+        Ok(Self(cue))
-    pub fn parse(data: &[u8]) -> Result<Self, Error> {
+    }
+}
+
+#[derive(Debug, PartialEq)]
+pub struct ARC<'a> {
+    data: &'a [u8],
+    file_count: u32,
+    version: u32,
+    cue: Cue,
+}
+
+impl<'a> ARC<'a> {
+    pub fn parse(data: &'a [u8]) -> Result<Self> {
         let mut cursor = Cursor::new(data);
 
         let magic = cursor.read_u32::<LE>()?;
@@ -82,33 +126,40 @@ impl ARC {
 
         let _compression = cursor.read_u32::<LE>()?;
 
-        let mut cue = Vec::new();
+        let mut cue_data = vec![0u8; (4 * 4 * file_count).try_into().unwrap()];
-        cursor
+        cursor.read_exact(&mut cue_data)?;
-            .take((4 * 4 * file_count).into())
+        let cue = Cue::parse(&cue_data, &data)?;
-            .read_to_end(&mut cue)?;
-        let cue: Vec<CueEntry> = cue
-            .chunks(4 * 4)
-            .map(CueEntry::parse)
-            .collect::<Result<_, _>>()?;
 
-        let mut files = HashMap::new();
+        info!("ARC archive has {} files", cue.len());
 
-        for entry in cue {
+        Ok(Self {
-            let path = PathBuf::from(
+            data,
-                String::from_utf8_lossy(
+            file_count,
-                    &mini_parser::get_slice_range(data, entry.name_offset..data.len())?
+            version,
-                        .iter()
+            cue,
-                        .take_while(|byte| **byte != 0)
+        })
-                        .cloned()
+    }
-                        .collect::<Vec<u8>>(),
-                )
-                .into_owned(),
-            );
 
-            trace!("Found entry with path {}", path.display());
+    pub fn has_file(&self, path: &PathBuf) -> bool {
+        self.cue.get(path).is_some()
+    }
+
+    pub fn file_paths(&self) -> Vec<&PathBuf> {
+        self.cue.keys().collect()
+    }
+
+    /// Gets a single file from the archive.
+    ///
+    /// Returns `Ok(None)` when the file does not exist and returns an error when the file could
+    /// not be read.
+    pub fn get_file(&self, path: &PathBuf) -> Result<Option<Vec<u8>>> {
+        let entry = match self.cue.get(path) {
+            Some(entry) => entry,
+            None => return Ok(None),
+        };
 
         let data = mini_parser::get_slice_range(
-                data,
+            self.data,
             entry.data_offset..entry.data_offset + entry.compressed_size,
         )?;
 
@@ -128,16 +179,85 @@ impl ARC {
         }
 
         debug!(
-                "Processed entry with path {} and length {}",
+            "Got file with path {} and length {}",
             path.display(),
             data.len()
         );
 
-            files.insert(path, data);
+        Ok(Some(data))
+    }
 }
 
-        info!("Processed {} files", files.len());
+#[cfg(test)]
+mod tests {
+    use super::*;
 
-        Ok(Self { files })
+    #[test]
+    fn test_cue_entry_parse() {
+        assert_eq!(
+            CueEntry::parse(b"\xa0\x00\x00\x00\xc0\x01\x00\x00\x5c\x04\x00\x00\x2d\x02\x00\x00")
+                .unwrap(),
+            CueEntry {
+                path_offset: 160,
+                data_offset: 448,
+                decompressed_size: 1116,
+                compressed_size: 557,
+            }
+        );
+    }
+
+    #[quickcheck]
+    fn test_cue_entry_parse_size(data: Vec<u8>) -> bool {
+        let cue_entry = CueEntry::parse(&data);
+        if dbg!(data.len()) >= 16 {
+            cue_entry.is_ok()
+        } else {
+            cue_entry.is_err()
+        }
+    }
+
+    #[test]
+    fn test_cue_entry_parse_path() {
+        let cue_entry = CueEntry {
+            path_offset: 7,
+            ..Default::default()
+        };
+        cue_entry.parse_path(b"").unwrap_err();
+        let path = cue_entry
+            .parse_path(b"1234567test/file/name\0after path")
+            .unwrap();
+        assert_eq!(path, PathBuf::from("test/file/name"));
+    }
+
+    #[test]
+    fn test_parse_cue() {
+        // only path_offset is required to have a useful value to test the cue
+        #[rustfmt::skip]
+        let cue = Cue::parse(&[
+            0x02, 0x00, 0x00, 0x00, // first file (path offset 2)
+            0x00, 0x00, 0x00, 0x00,
+            0x00, 0x00, 0x00, 0x00,
+            0x00, 0x00, 0x00, 0x00,
+            0x0f, 0x00, 0x00, 0x00, // second file (path offset 15)
+            0x00, 0x00, 0x00, 0x00,
+            0x00, 0x00, 0x00, 0x00,
+            0x00, 0x00, 0x00, 0x00,
+        ], b"abpath/to/file\0other/file\0z").unwrap();
+        let mut expected_cue = HashMap::new();
+        expected_cue.insert(
+            PathBuf::from("path/to/file"),
+            CueEntry {
+                path_offset: 2,
+                ..Default::default()
+            },
+        );
+        expected_cue.insert(
+            PathBuf::from("other/file"),
+            CueEntry {
+                path_offset: 15,
+                ..Default::default()
+            },
+        );
+        assert_eq!(cue, Cue(expected_cue));
     }
 }

src/ddr/musicdb.rs

@@ -78,8 +78,7 @@ impl MusicDB {
         let arc = arc::ARC::parse(&data)?;
 
         let musicdb_data = arc
-            .files
+            .get_file(&PathBuf::from("data/gamedata/musicdb.xml"))?
-            .get(&PathBuf::from("data/gamedata/musicdb.xml"))
             .ok_or(Error::NotInArchive)?;
 
         Self::parse(&String::from_utf8(musicdb_data.to_vec())?).map_err(|err| err.into())

src/main.rs

@@ -306,19 +306,23 @@ fn main() -> Result<()> {
                 .with_context(|| format!("failed to read ARC file {}", &opts.file.display()))?;
             let arc = ARC::parse(&arc_data).context("failed to parse ARC file")?;
 
-            let files = match opts.single_file {
+            let files = match &opts.single_file {
-                Some(path) => match arc.files.get(&path) {
+                Some(path) => {
-                    Some(_) => vec![path],
+                    if arc.has_file(&path) {
-                    None => return Err(anyhow!("File “{}” not found in archive", path.display())),
+                        vec![path]
-                },
+                    } else {
-                None => arc.files.keys().cloned().collect(),
+                        return Err(anyhow!("File “{}” not found in archive", path.display()));
+                    }
+                }
+                None => arc.file_paths(),
             };
 
-            for (path, data) in arc.files.iter() {
+            for path in arc.file_paths() {
                 if files.contains(&path) {
                     if opts.list_files {
                         println!("{}", path.display());
                     } else {
+                        let data = arc.get_file(path)?.unwrap();
                         info!("Writing {}", path.display());
                         if let Some(parent) = path.parent() {
                             fs::create_dir_all(parent)?;