diff --git a/src/fot/decoder.rs b/src/fot/decoder.rs
index 2800a1c..41990e5 100644
--- a/src/fot/decoder.rs
+++ b/src/fot/decoder.rs
@@ -4,7 +4,7 @@ use super::raw::Raw;
 
 pub trait Decoder: Sized {
     fn decode(raw: &Raw, offset: usize, size: usize) -> Result<Self>;
-    fn encode(&self) -> Raw;
+    fn encode(&self) -> Result<Raw>;
     fn get_enc_size(&self) -> usize;
 }
 
@@ -17,10 +17,10 @@ impl Decoder for String {
         }
     }
 
-    fn encode(&self) -> Raw {
+    fn encode(&self) -> Result<Raw> {
         let mut str = self.as_bytes().to_vec();
         str.push(0);
-        Raw { offset: 0, size: str.len(), mem: str}
+        Ok(Raw { offset: 0, size: str.len(), mem: str})
     }
 
     fn get_enc_size(&self) -> usize {
diff --git a/src/fot/fstring.rs b/src/fot/fstring.rs
index be9789a..97ad53c 100644
--- a/src/fot/fstring.rs
+++ b/src/fot/fstring.rs
@@ -38,21 +38,21 @@ impl Decoder for FString {
         }
     }
 
-    fn encode(&self) -> Raw {
+    fn encode(&self) -> Result<Raw> {
         let mut buf = vec![0u8; 4];
         let mut wdr = Cursor::new(&mut buf[..]);
         if self.encoding == FStringEncoding::ANSI {
-            let _ = wdr.write_u32::<LittleEndian>(self.str.len() as u32 ^ (1<<31));
+            wdr.write_u32::<LittleEndian>(self.str.len() as u32 ^ (1<<31))?;
             buf.append(&mut self.str.clone().into_bytes());
         } else { // WCS2
             let (chars, _, _) = WINDOWS_1251.encode(self.str.as_str());
-            let _ = wdr.write_u32::<LittleEndian>(chars.len() as u32 | (1<<31));
+            wdr.write_u32::<LittleEndian>(chars.len() as u32 | (1<<31))?;
             for &c in chars.iter() {
                 buf.push(c);
                 buf.push(0);
             }
         };
-        Raw { offset: 0, size: buf.len(), mem: buf }
+        Ok(Raw { offset: 0, size: buf.len(), mem: buf })
     }
 
     fn get_enc_size(&self) -> usize {
diff --git a/src/fot/save.rs b/src/fot/save.rs
index 7c930d6..154288d 100644
--- a/src/fot/save.rs
+++ b/src/fot/save.rs
@@ -52,7 +52,7 @@ impl Save {
 
     pub fn save(&self, path: &Path) -> Result<()> {
         self.raw.assemble_file(path, vec![
-            self.world.encode()
+            self.world.encode()?
         ])?;
 
         Ok(())
diff --git a/src/fot/tag.rs b/src/fot/tag.rs
index 5f9dab2..955651e 100644
--- a/src/fot/tag.rs
+++ b/src/fot/tag.rs
@@ -15,11 +15,11 @@ impl Decoder for Tag {
         Ok(Tag {name, version})
     }
 
-    fn encode(&self) -> Raw {
-        Raw::join(0, self.get_enc_size(), &mut [
-            self.name.encode(),
-            self.version.encode()
-        ])
+    fn encode(&self) -> Result<Raw> {
+        Ok(Raw::join(0, self.get_enc_size(), &mut [
+            self.name.encode()?,
+            self.version.encode()?
+        ]))
     }
 
     fn get_enc_size(&self) -> usize {
diff --git a/src/fot/world.rs b/src/fot/world.rs
index e200800..71e3848 100644
--- a/src/fot/world.rs
+++ b/src/fot/world.rs
@@ -45,7 +45,7 @@ impl Decoder for World {
         Ok(World { tag, uncompressed_size, data: Raw { offset, size, mem: data } })
     }
 
-    fn encode(&self) -> Raw {
+    fn encode(&self) -> Result<Raw> {
         let mut hdr = [0u8; 8];
         {
             let mut wdr = Cursor::new(&mut hdr[..]);
@@ -54,11 +54,11 @@ impl Decoder for World {
         }
         let data = deflate_bytes_zlib(&self.data.mem);
 
-        Raw::join(self.data.offset, self.data.size, &mut [
-            self.tag.encode(),
+        Ok(Raw::join(self.data.offset, self.data.size, &mut [
+            self.tag.encode()?,
             Raw { offset: Self::WORLD_TAG_LEN, size: 8, mem: hdr.to_vec()},
             Raw { offset: Self::WORLD_HDR_LEN, size: data.len(), mem: data}
-        ])
+        ]))
     }
 
     fn get_enc_size(&self) -> usize {