Properly write 'version needed' in local file header

'version made by' was used instead of version needed by accident.

Resolves #72

src/types.rs

@@ -79,6 +79,14 @@ impl ZipFileData {
                 path
             })
     }
+
+    pub fn version_needed(&self) -> u16 {
+        match self.compression_method {
+            #[cfg(feature = "bzip2")]
+            ::compression::CompressionMethod::Bzip2 => 46,
+            _ => 20,
+        }
+    }
 }
 
 #[cfg(test)]

src/write.rs

@@ -424,8 +424,7 @@ fn write_local_file_header<T: Write>(writer: &mut T, file: &ZipFileData) -> ZipR
     // local file header signature
     try!(writer.write_u32::<LittleEndian>(spec::LOCAL_FILE_HEADER_SIGNATURE));
     // version needed to extract
-    let version_made_by = (file.system as u16) << 8 | (file.version_made_by as u16);
-    try!(writer.write_u16::<LittleEndian>(version_made_by));
+    try!(writer.write_u16::<LittleEndian>(file.version_needed()));
     // general purpose bit flag
     let flag = if !file.file_name.is_ascii() { 1u16 << 11 } else { 0 };
     try!(writer.write_u16::<LittleEndian>(flag));
@@ -472,7 +471,7 @@ fn write_central_directory_header<T: Write>(writer: &mut T, file: &ZipFileData)
     let version_made_by = (file.system as u16) << 8 | (file.version_made_by as u16);
     try!(writer.write_u16::<LittleEndian>(version_made_by));
     // version needed to extract
-    try!(writer.write_u16::<LittleEndian>(20));
+    try!(writer.write_u16::<LittleEndian>(file.version_needed()));
     // general puprose bit flag
     let flag = if !file.file_name.is_ascii() { 1u16 << 11 } else { 0 };
     try!(writer.write_u16::<LittleEndian>(flag));