diff --git a/src/storage/file.rs b/src/storage/file.rs
index 3007f6d3..0d0df446 100644
--- a/src/storage/file.rs
+++ b/src/storage/file.rs
@@ -1,3 +1,8 @@
+use std::error::Error;
+use std::fmt::{Debug, Display, Formatter};
+use std::fmt;
+
+#[derive(Debug)]
 pub enum FileHeaderSpec {
     Null,
     Bool,
@@ -9,6 +14,7 @@ pub enum FileHeaderSpec {
     Array { allowed_types: Box<Vec<FileHeaderSpec>> },
 }
 
+#[derive(Debug)]
 pub enum FileHeaderData {
     Null,
     Bool(bool),
@@ -25,3 +31,120 @@ pub trait FileData : Sized {
     fn get_abbrev(&self) -> String;
 }
 
+impl Display for FileHeaderSpec {
+
+    fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
+        match self {
+            &FileHeaderSpec::Null       => write!(fmt, "NULL"),
+            &FileHeaderSpec::Bool       => write!(fmt, "Bool"),
+            &FileHeaderSpec::Integer    => write!(fmt, "Integer"),
+            &FileHeaderSpec::UInteger   => write!(fmt, "UInteger"),
+            &FileHeaderSpec::Float      => write!(fmt, "Float"),
+            &FileHeaderSpec::Text       => write!(fmt, "Text"),
+            &FileHeaderSpec::Key{name: ref n, value_type: ref vt} => {
+                write!(fmt, "Key({:?}) -> {:?}", n, vt)
+            }
+            &FileHeaderSpec::Array{allowed_types: ref at}  => {
+                write!(fmt, "Array({:?})", at)
+            }
+        }
+    }
+
+}
+
+pub struct MatchError<'a> {
+    summary: String,
+    expected: &'a FileHeaderSpec,
+    found: &'a FileHeaderData
+}
+
+impl<'a> MatchError<'a> {
+
+    pub fn new(s: String,
+               ex: &'a FileHeaderSpec,
+               found: &'a FileHeaderData) -> MatchError<'a> {
+        MatchError {
+            summary: s,
+            expected: ex,
+            found: found,
+        }
+    }
+
+    pub fn format(&self) -> String {
+        format!("MatchError: {:?}\nExpected: {:?}\nFound: {:?}\n",
+               self.summary, self.expected, self.found)
+    }
+}
+
+impl<'a> Error for MatchError<'a> {
+
+    fn description(&self) -> &str {
+        &self.summary[..]
+    }
+
+    fn cause(&self) -> Option<&Error> {
+        None
+    }
+
+}
+
+impl<'a> Debug for MatchError<'a> {
+
+    fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
+        write!(fmt, "{}", self.format());
+        Ok(())
+    }
+
+}
+
+impl<'a> Display for MatchError<'a> {
+
+    fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
+        write!(fmt, "{}", self.format());
+        Ok(())
+    }
+
+}
+
+pub fn match_header_spec<'a>(spec: &'a FileHeaderSpec, data: &'a FileHeaderData)
+    -> Option<MatchError<'a>>
+{
+    match (spec, data) {
+        (&FileHeaderSpec::Null,     &FileHeaderData::Null)           => { }
+        (&FileHeaderSpec::Bool,     &FileHeaderData::Bool(_))        => { }
+        (&FileHeaderSpec::Integer,  &FileHeaderData::Integer(_))     => { }
+        (&FileHeaderSpec::UInteger, &FileHeaderData::UInteger(_))    => { }
+        (&FileHeaderSpec::Float,    &FileHeaderData::Float(_))       => { }
+        (&FileHeaderSpec::Text,     &FileHeaderData::Text(_))        => { }
+
+        (
+            &FileHeaderSpec::Key{name: ref kname, value_type: ref vtype},
+            &FileHeaderData::Key{name: ref n, value: ref val}
+        ) => {
+            if kname != n {
+                // error
+            }
+            return match_header_spec(&*vtype, &*val);
+        }
+
+        (
+            &FileHeaderSpec::Array{allowed_types: ref vtypes},
+            &FileHeaderData::Array{values: ref vs}
+        ) => {
+            for (t, v) in vtypes.iter().zip(vs.iter()) {
+                let res = match_header_spec(t, v);
+                if res.is_some() {
+                    return res;
+                }
+            }
+        }
+
+        (k, v) => {
+            return Some(MatchError::new(String::from("Expected type does not match found type"),
+                                 k, v
+                                 ))
+        }
+    }
+    None
+}
+