diff --git a/src/file.rs b/src/file.rs
index d9ebb14..f3a2473 100644
--- a/src/file.rs
+++ b/src/file.rs
@@ -1,8 +1,9 @@
 //file format "sniff"
 
+use binrw::{binrw, BinReaderExt};
+
 pub enum Error{
-	InvalidMagic,
-	InvalidVersion,
+	InvalidHeader(binrw::Error),
 	UnexpectedEOF,
 }
 
@@ -33,13 +34,19 @@ for block_id in 0..num_blocks{
 //each block is compressed with zstd or gz or something
 
 */
+#[binrw]
+#[brw(little)]
 #[derive(Clone,Copy)]
 pub(crate) enum FourCC{
+	#[brw(magic=b"SNFM")]
 	Map,
+	#[brw(magic=b"SNFB")]
 	Bot,
+	#[brw(magic=b"SNFD")]
 	Demo,
 }
-
+#[binrw]
+#[brw(little)]
 struct Header{
 	/// Type of file
 	fourcc:FourCC,
@@ -49,25 +56,23 @@ struct Header{
 	priming:u64,
 	/// uuid for this file
 	resource:u128,
+	#[bw(try_calc(u64::try_from(block_location.len())))]
+	block_count:u64,
+	#[br(count=block_count)]
+	block_location:Vec<u64>,
 }
 
-pub(crate) struct BlockLayout{
-	count:u64,
-	location:Vec<u64>,
-}
 
 pub(crate) struct File{
 	header:Header,
-	block_layout:BlockLayout,
 	//reference to the data
 }
 
 impl File{
-	pub(crate) fn new<R:std::io::Read+std::io::Seek>(input:R)->Result<Self,Error>{
-		Self{
-			header:input.read_le()?,
-			block_layout:input.read_le()?,
-		}
+	pub(crate) fn new<R:BinReaderExt>(mut input:R)->Result<Self,Error>{
+		Ok(Self{
+			header:input.read_le().map_err(|e|Error::InvalidHeader(e))?,
+		})
 	}
 	pub(crate) fn read_block(&mut self,block_id:u64)->Result<Vec<u8>,Error>{
 		Err(Error::UnexpectedEOF)
diff --git a/src/lib.rs b/src/lib.rs
index 2777453..6ea292d 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,4 +1,4 @@
-use std::io::Read;
+use binrw::BinReaderExt;
 
 pub mod file;
 pub mod map;
@@ -19,30 +19,30 @@ pub enum SNF{
 	Demo(demo::StreamableDemo),
 }
 
-pub fn read_snf<R:Read>(input:R)->Result<SNF,Error>{
-	let file=file::File::read(input).map_err(|e|Error::Header(e))?;
+pub fn read_snf<R:BinReaderExt>(input:R)->Result<SNF,Error>{
+	let file=file::File::new(input).map_err(|e|Error::Header(e))?;
 	Ok(match file.fourcc(){
 		file::FourCC::Map=>SNF::Map(map::StreamableMap::new(file).map_err(|e|Error::Map(e))?),
 		file::FourCC::Bot=>SNF::Bot(bot::StreamableBot::new(file).map_err(|e|Error::Bot(e))?),
 		file::FourCC::Demo=>SNF::Demo(demo::StreamableDemo::new(file).map_err(|e|Error::Demo(e))?),
 	})
 }
-pub fn read_map<R:Read>(input:R)->Result<map::StreamableMap,Error>{
-	let file=file::File::read(input).map_err(|e|Error::Header(e))?;
+pub fn read_map<R:BinReaderExt>(input:R)->Result<map::StreamableMap,Error>{
+	let file=file::File::new(input).map_err(|e|Error::Header(e))?;
 	match file.fourcc(){
 		file::FourCC::Map=>Ok(map::StreamableMap::new(file).map_err(|e|Error::Map(e))?),
 		_=>Err(Error::UnexpectedFourCC)
 	}
 }
-pub fn read_bot<R:Read>(input:R)->Result<bot::StreamableBot,Error>{
-	let file=file::File::read(input).map_err(|e|Error::Header(e))?;
+pub fn read_bot<R:BinReaderExt>(input:R)->Result<bot::StreamableBot,Error>{
+	let file=file::File::new(input).map_err(|e|Error::Header(e))?;
 	match file.fourcc(){
 		file::FourCC::Bot=>Ok(bot::StreamableBot::new(file).map_err(|e|Error::Bot(e))?),
 		_=>Err(Error::UnexpectedFourCC)
 	}
 }
-pub fn read_demo<R:Read>(input:R)->Result<demo::StreamableDemo,Error>{
-	let file=file::File::read(input).map_err(|e|Error::Header(e))?;
+pub fn read_demo<R:BinReaderExt>(input:R)->Result<demo::StreamableDemo,Error>{
+	let file=file::File::new(input).map_err(|e|Error::Header(e))?;
 	match file.fourcc(){
 		file::FourCC::Demo=>Ok(demo::StreamableDemo::new(file).map_err(|e|Error::Demo(e))?),
 		_=>Err(Error::UnexpectedFourCC)