diff --git a/source/durandal/bin.rs b/source/durandal/bin.rs
index e5124a5..b2dc0aa 100644
--- a/source/durandal/bin.rs
+++ b/source/durandal/bin.rs
@@ -476,6 +476,22 @@ impl OptU16
          Some(n) => Some(n.get() - 1),
       }
    }
+
+   /// Return the memory representation of this integer as a byte array
+   /// in big-endian (network) byte order.
+   #[inline]
+   pub fn to_be_bytes(self) -> [u8; 2]
+   {
+      <Self as Into<u16>>::into(self).to_be_bytes()
+   }
+
+   /// Return the memory representation of this integer as a byte array
+   /// in little-endian byte order.
+   #[inline]
+   pub fn to_le_bytes(self) -> [u8; 2]
+   {
+      <Self as Into<u16>>::into(self).to_le_bytes()
+   }
 }
 
 impl fmt::Debug for OptU16
diff --git a/source/durandal/cksum.rs b/source/durandal/cksum.rs
index 7441ae7..08a359a 100644
--- a/source/durandal/cksum.rs
+++ b/source/durandal/cksum.rs
@@ -1,4 +1,4 @@
-//! Cyclic redundancy check function.
+//! Checksum functions.
 
 fn crc_accum(a: u32, _: u32) -> u32
 {
diff --git a/source/marathon/map.rs b/source/marathon/map.rs
index 2da456c..c02babe 100644
--- a/source/marathon/map.rs
+++ b/source/marathon/map.rs
@@ -20,6 +20,18 @@ pub fn read_lightfunc(b: &[u8]) -> ResultS<LightFunc>
    Ok(LightFunc{ftype, prd_nrm, prd_dta, val_nrm, val_dta})
 }
 
+/// Writes a `LightFunc` object.
+pub fn write_lightfunc(v: &LightFunc) -> Vec<u8>
+{
+   let mut o = Vec::with_capacity(14);
+   o.extend(&(v.ftype as u16).to_be_bytes());
+   o.extend(&v.prd_nrm.to_be_bytes());
+   o.extend(&v.prd_dta.to_be_bytes());
+   o.extend(&v.val_nrm.to_be_bytes());
+   o.extend(&v.val_dta.to_be_bytes());
+   o
+}
+
 /// Reads a `SideTex` object.
 pub fn read_sidetex(b: &[u8]) -> ResultS<SideTex>
 {
@@ -33,6 +45,15 @@ pub fn read_sidetex(b: &[u8]) -> ResultS<SideTex>
    Ok(SideTex{offs, tex_id})
 }
 
+/// Writes a `SideTex` object.
+pub fn write_sidetex(v: &SideTex) -> Vec<u8>
+{
+   let mut o = Vec::with_capacity(6);
+   o.extend(write_point(&v.offs));
+   o.extend(&v.tex_id.to_be_bytes());
+   o
+}
+
 /// Reads a `Point` object.
 pub fn read_point(b: &[u8]) -> ResultS<Point>
 {
@@ -46,6 +67,15 @@ pub fn read_point(b: &[u8]) -> ResultS<Point>
    Ok(Point{x, y})
 }
 
+/// Writes a `Point` object.
+pub fn write_point(v: &Point) -> Vec<u8>
+{
+   let mut o = Vec::with_capacity(4);
+   o.extend(&v.x.to_be_bytes());
+   o.extend(&v.y.to_be_bytes());
+   o
+}
+
 /// Reads a `Minf` chunk.
 pub fn read_minf(b: &[u8]) -> ResultS<Minf>
 {
@@ -65,6 +95,20 @@ pub fn read_minf(b: &[u8]) -> ResultS<Minf>
            entr_flags, level_name})
 }
 
+/// Writes a `Minf` chunk.
+pub fn write_minf(v: &Minf) -> Vec<u8>
+{
+   let mut o = Vec::with_capacity(4);
+   o.extend(&v.texture_id.to_be_bytes());
+   o.extend(&v.physics_id.to_be_bytes());
+   o.extend(&v.skypict_id.to_be_bytes());
+   o.extend(&v.miss_flags.bits().to_be_bytes());
+   o.extend(&v.envi_flags.bits().to_be_bytes());
+   o.extend(&pad_0(to_mac_roman(v.level_name), 66));
+   o.extend(&v.entr_flags.bits().to_be_bytes());
+   o
+}
+
 /// Reads an old `Minf` chunk.
 pub fn read_old_minf(b: &[u8]) -> ResultS<Minf>
 {