Merge pull request #44 from vswarte/fix/remove-padding-bytes-from-bdt…

…-entry-reader-output

Remove padding bytes from DvdBnd entry reader output

crates/dvdbnd/src/lib.rs

@@ -154,7 +154,17 @@ impl DvdBnd {
                 #[cfg(unix)]
                 let _ = mmap.advise(memmap2::Advice::Sequential);
 
-                Ok(DvdBndEntryReader::new(mmap.make_read_only()?))
+                // DCXes dont have an unpadded size set
+                let effective_file_size = if entry.file_size != 0 {
+                    entry.file_size
+                } else {
+                    entry.file_size_with_padding
+                } as usize;
+
+                Ok(DvdBndEntryReader::new(
+                    mmap.make_read_only()?,
+                    effective_file_size,
+                ))
             }
             None => Err(DvdBndEntryError::NotFound),
         }

crates/dvdbnd/src/reader.rs

@@ -5,18 +5,25 @@ use memmap2::Mmap;
 pub struct DvdBndEntryReader {
     mmap: Mmap,
     position: usize,
+    length: usize,
 }
 
 impl DvdBndEntryReader {
-    pub fn new(mmap: Mmap) -> Self {
-        Self { mmap, position: 0 }
+    pub fn new(mmap: Mmap, length: usize) -> Self {
+        Self {
+            mmap,
+            position: 0,
+            length,
+        }
     }
 
     pub fn data(&self) -> &[u8] {
-        &self.mmap[..]
+        &self.mmap[..self.length]
     }
 }
 
+// Do we really need this? With the length being a thing now to deal with the
+// padding on the output this conversion is no longer lossless.
 impl From<DvdBndEntryReader> for Mmap {
     fn from(value: DvdBndEntryReader) -> Self {
         value.mmap
@@ -25,7 +32,7 @@ impl From<DvdBndEntryReader> for Mmap {
 
 impl Read for DvdBndEntryReader {
     fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
-        let mut data = &self.mmap[self.position..];
+        let mut data = &self.data()[self.position..];
         let read = data.read(buf)?;
 
         self.position += read;
@@ -38,12 +45,12 @@ impl Seek for DvdBndEntryReader {
     fn seek(&mut self, pos: SeekFrom) -> std::io::Result<u64> {
         let new_pos = match pos {
             SeekFrom::Start(start_offset) => Some(start_offset as usize),
-            SeekFrom::End(end_offset) => self.mmap.len().checked_add_signed(end_offset as isize),
+            SeekFrom::End(end_offset) => self.data().len().checked_add_signed(end_offset as isize),
             SeekFrom::Current(offset) => self.position.checked_add_signed(offset as isize),
         }
         .ok_or(Error::other("invalid seek offset"))?;
 
-        if new_pos < self.mmap.len() {
+        if new_pos < self.data().len() {
             self.position = new_pos;
             Ok(self.position as u64)
         } else {