From c6dd2ad26bed4876500e0a8780e79b2edbfea9d3 Mon Sep 17 00:00:00 2001
From: Mathijs van de Nes <git@mathijs.vd-nes.nl>
Date: Wed, 17 Sep 2014 15:11:56 +0200
Subject: [PATCH] Update the local header instead of overwriting

---
 src/writer.rs      |  3 +--
 src/writer_spec.rs | 10 ++++++++++
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/writer.rs b/src/writer.rs
index 2b5f4d0b..8de35b4a 100644
--- a/src/writer.rs
+++ b/src/writer.rs
@@ -152,8 +152,7 @@ impl<W: Writer+Seek> ZipWriter<W>
         file.uncompressed_size = self.stats.bytes_written;
         file.compressed_size = try!(writer.tell()) - self.stats.start;
 
-        try!(writer.seek(file.header_start as i64, io::SeekSet));
-        try!(writer_spec::write_local_file_header(writer, file));
+        try!(writer_spec::update_local_file_header(writer, file));
         try!(writer.seek(0, io::SeekEnd));
         Ok(())
     }
diff --git a/src/writer_spec.rs b/src/writer_spec.rs
index 2dd8c82f..54bf2e2a 100644
--- a/src/writer_spec.rs
+++ b/src/writer_spec.rs
@@ -25,6 +25,16 @@ pub fn write_local_file_header<T: Writer>(writer: &mut T, file: &ZipFile) -> IoR
     Ok(())
 }
 
+pub fn update_local_file_header<T: Writer+Seek>(writer: &mut T, file: &ZipFile) -> IoResult<()>
+{
+    static CRC32_OFFSET : i64 = 14;
+    try!(writer.seek(file.header_start as i64 + CRC32_OFFSET, io::SeekSet));
+    try!(writer.write_le_u32(file.crc32));
+    try!(writer.write_le_u32(file.compressed_size as u32));
+    try!(writer.write_le_u32(file.uncompressed_size as u32));
+    Ok(())
+}
+
 pub fn write_central_directory_header<T: Writer>(writer: &mut T, file: &ZipFile) -> IoResult<()>
 {
     try!(writer.write_le_u32(spec::CENTRAL_DIRECTORY_HEADER_SIGNATURE));