Reading, fix writing, monocommit

18 files changed, 1347 insertions, 639 deletions

diff --git a/Cargo.toml b/Cargo.toml
index f4ffb22..ae6962b 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -12,6 +12,8 @@ criterion = "0.3"
 rand = "0.7.3"
 
 [dependencies]
+weezl = "0.1.5"
+owo-colors = "2.0.0"
 
 [[bench]]
 name = "lzw_encode"
diff --git a/src/block/colortable.rs b/src/block/colortable.rs
index 97b428f..da9458c 100644
--- a/src/block/colortable.rs
+++ b/src/block/colortable.rs
@@ -1,67 +1,82 @@
-use std::ops::Deref;
 pub use crate::Color;
+use std::{
+    convert::{TryFrom, TryInto},
+    ops::Deref,
+};
 
 pub struct ColorTable {
-	table: Vec<Color>
+    table: Vec<Color>,
 }
 
 impl ColorTable {
-	pub fn new() -> Self {
-		Self {
-			table: vec![]
-		}
-	}
+    pub fn new() -> Self {
+        Self { table: vec![] }
+    }
 
-	/// Returns the number of colors in the color table as used by the packed
-	/// fields in the Logical Screen Descriptor and Image Descriptor. You can
-	/// get the actual size with the [`len`](struct.ColorTable.html#method.len) method.
-	pub fn packed_len(&self) -> u8 {
-		((self.table.len() as f32).log2().ceil() - 1f32) as u8
-	}
+    /// Returns the number of colors in the color table as used by the packed
+    /// fields in the Logical Screen Descriptor and Image Descriptor. You can
+    /// get the actual size with the [`len`](struct.ColorTable.html#method.len) method.
+    pub fn packed_len(&self) -> u8 {
+        ((self.table.len() as f32).log2().ceil() - 1f32) as u8
+    }
 
-	/// Returns the number of items in the table
-	pub fn len(&self) -> usize {
-		self.table.len()
-	}
+    /// Returns the number of items in the table
+    pub fn len(&self) -> usize {
+        self.table.len()
+    }
 
-	/// Pushes a color on to the end of the table
-	pub fn push(&mut self, color: Color) {
-		self.table.push(color);
-	}
+    /// Pushes a color on to the end of the table
+    pub fn push(&mut self, color: Color) {
+        self.table.push(color);
+    }
 }
 
 impl Deref for ColorTable {
-	type Target = [Color];
+    type Target = [Color];
 
-	fn deref(&self) -> &Self::Target {
-		&self.table
-	}
+    fn deref(&self) -> &Self::Target {
+        &self.table
+    }
 }
 
 impl From<Vec<Color>> for ColorTable {
-	fn from(table: Vec<Color>) -> Self{
-		ColorTable {
-			table
-		}
-	}
+    fn from(table: Vec<Color>) -> Self {
+        ColorTable { table }
+    }
 }
 
 impl From<&ColorTable> for Box<[u8]> {
-	fn from(table: &ColorTable) -> Self {
-		let mut vec = vec![];
+    fn from(table: &ColorTable) -> Self {
+        let mut vec = vec![];
 
-		for color in table.iter() {
-			vec.extend_from_slice(&[color.r, color.g, color.b]);
-		}
+        for color in table.iter() {
+            vec.extend_from_slice(&[color.r, color.g, color.b]);
+        }
 
-		let packed_len = 2u8.pow(table.packed_len() as u32 + 1);
-		let padding = (packed_len as usize - table.len()) * 3;
-		if padding > 0 {
-			vec.extend_from_slice(&vec![0; padding]);
-		}
+        let packed_len = 2usize.pow(table.packed_len() as u32 + 1);
+        let padding = (packed_len as usize - table.len()) * 3;
+        if padding > 0 {
+            vec.extend_from_slice(&vec![0; padding]);
+        }
 
-		vec.into_boxed_slice()
-	}
+        vec.into_boxed_slice()
+    }
 }
 
-//TODO: TryFrom Vec<u8> (must be multiple of 3 len) and From Vec<Color>
\ No newline at end of file
+//TODO: TryFrom Vec<u8> (must be multiple of 3 len) and From Vec<Color>
+impl TryFrom<&[u8]> for ColorTable {
+    type Error = ();
+
+    fn try_from(value: &[u8]) -> Result<Self, Self::Error> {
+        if value.len() % 3 != 0 {
+            return Err(());
+        } else {
+            Ok(Self {
+                table: value
+                    .chunks(3)
+                    .map(|slice| Color::from(TryInto::<[u8; 3]>::try_into(slice).unwrap()))
+                    .collect::<Vec<Color>>(),
+            })
+        }
+    }
+}
diff --git a/src/block/extension/application.rs b/src/block/extension/application.rs
new file mode 100644
index 0000000..b3516d8
--- /dev/null
+++ b/src/block/extension/application.rs
@@ -0,0 +1,15 @@
+pub struct Application {
+    pub(crate) identifier: String, // max len 8
+    pub(crate) authentication_code: [u8; 3],
+    pub(crate) data: Vec<u8>,
+}
+
+impl Application {
+    pub fn identifier(&self) -> &str {
+        &self.identifier
+    }
+
+    pub fn authentication_code(&self) -> &[u8] {
+        &self.authentication_code
+    }
+}
diff --git a/src/block/extension/graphiccontrol.rs b/src/block/extension/graphiccontrol.rs
index 46f44fa..0d4edd1 100644
--- a/src/block/extension/graphiccontrol.rs
+++ b/src/block/extension/graphiccontrol.rs
@@ -1,59 +1,86 @@
+use std::convert::TryInto;
+
+#[derive(Clone, Debug)]
 pub struct GraphicControl {
-	pub(crate) packed: u8,
-	pub(crate) delay_time: u16,
-	pub(crate) transparency_index: u8
+    pub(crate) packed: u8,
+    pub(crate) delay_time: u16,
+    pub(crate) transparency_index: u8,
 }
 
 impl GraphicControl {
-	pub fn new(disposal_method: DisposalMethod, user_input_flag: bool, transparency_flag: bool, delay_time: u16, transparency_index: u8) -> Self {
-		let mut ret = Self {
-			packed: 0,
-			delay_time,
-			transparency_index
-		};
-
-		ret.disposal_method(disposal_method);
-		ret.user_input(user_input_flag);
-		ret.transparency(transparency_flag);
-
-		ret
-	}
-
-	pub fn disposal_method(&mut self, method: DisposalMethod) {
-		match method {
-			DisposalMethod::Clear => self.packed &= 0b111_000_1_1,
-			DisposalMethod::DoNotDispose => self.packed |= 0b000_100_0_0,
-			DisposalMethod::RestoreBackground => self.packed |= 0b000_010_0_0,
-			DisposalMethod::RestorePrevious => self.packed |= 0b000_110_0_0
-		};
-	}
-
-	pub fn user_input(&mut self, flag: bool) {
-		if flag {
-			self.packed |= 0b000_000_1_0;
-		} else {
-			self.packed &= 0b111_111_0_1;
-		}
-	}
-
-	pub fn transparency(&mut self, flag: bool) {
-		if flag {
-			self.packed |= 0b000_000_0_1;
-		} else {
-			self.packed &= 0b111_111_1_0;
-		}
-	}
-
-	pub fn delay_time(&mut self, hundreths: u16) {
-		self.delay_time = hundreths;
-	}
-
-	//TODO: Transparency index setter
+    pub fn new(
+        disposal_method: DisposalMethod,
+        user_input_flag: bool,
+        transparency_flag: bool,
+        delay_time: u16,
+        transparency_index: u8,
+    ) -> Self {
+        let mut ret = Self {
+            packed: 0,
+            delay_time,
+            transparency_index,
+        };
+
+        ret.disposal_method(disposal_method);
+        ret.user_input(user_input_flag);
+        ret.transparency(transparency_flag);
+
+        ret
+    }
+
+    pub fn disposal_method(&mut self, method: DisposalMethod) {
+        match method {
+            DisposalMethod::Clear => self.packed &= 0b111_000_1_1,
+            DisposalMethod::DoNotDispose => self.packed |= 0b000_100_0_0,
+            DisposalMethod::RestoreBackground => self.packed |= 0b000_010_0_0,
+            DisposalMethod::RestorePrevious => self.packed |= 0b000_110_0_0,
+        };
+    }
+
+    pub fn user_input(&mut self, flag: bool) {
+        if flag {
+            self.packed |= 0b000_000_1_0;
+        } else {
+            self.packed &= 0b111_111_0_1;
+        }
+    }
+
+    pub fn transparency(&mut self, flag: bool) {
+        if flag {
+            self.packed |= 0b000_000_0_1;
+        } else {
+            self.packed &= 0b111_111_1_0;
+        }
+    }
+
+    pub fn delay_time(&self) -> u16 {
+        self.delay_time
+    }
+
+    pub fn delay_time_mut(&mut self) -> &mut u16 {
+        &mut self.delay_time
+    }
+
+    //TODO: Transparency index setter
+}
+
+impl From<[u8; 4]> for GraphicControl {
+    fn from(arr: [u8; 4]) -> Self {
+        let packed = arr[0];
+        let delay_time = u16::from_le_bytes(arr[1..3].try_into().unwrap());
+        let transparency_index = arr[3];
+
+        Self {
+            packed,
+            delay_time,
+            transparency_index,
+        }
+    }
 }
 
 pub enum DisposalMethod {
-	Clear,
-	DoNotDispose,
-	RestoreBackground,
-	RestorePrevious
-}
\ No newline at end of file
+    Clear,
+    DoNotDispose,
+    RestoreBackground,
+    RestorePrevious,
+}
diff --git a/src/block/extension/mod.rs b/src/block/extension/mod.rs
index 66a39b0..d0e57c6 100644
--- a/src/block/extension/mod.rs
+++ b/src/block/extension/mod.rs
@@ -1,39 +1,43 @@
+mod application;
 mod graphiccontrol;
 
 pub use graphiccontrol::{DisposalMethod, GraphicControl};
 
+pub use self::application::Application;
+
 pub enum Extension {
-	GraphicControl(GraphicControl),
-	Looping(u16)
-	// Comment
-	// Plain Text
-	// Generic Application
+    GraphicControl(GraphicControl),
+    Looping(u16),
+    Comment(Vec<u8>), // Plain Text
+    Application(Application),
 }
 
 impl From<&Extension> for Box<[u8]> {
-	fn from(ext: &Extension) -> Self {
-		let mut vec = vec![];
-		vec.push(0x21); // Push the extension introducer
+    fn from(ext: &Extension) -> Self {
+        let mut vec = vec![];
+        vec.push(0x21); // Push the extension introducer
 
-		match ext {
-			Extension::GraphicControl(gc) => {
-				vec.push(0xF9); // Graphic control label
-				vec.push(0x04); // Block size for this extension is always 4
-				vec.push(gc.packed);
-				vec.extend_from_slice(&gc.delay_time.to_le_bytes());
-				vec.push(gc.transparency_index);
-			},
-			Extension::Looping(count) => {
-				vec.push(0xFF); // Application extension label
-				vec.push(0x0B); // 11 bytes in this block
-				vec.extend_from_slice(b"NETSCAPE2.0"); // App. ident. and "auth code"
-				vec.push(0x03); // Sub-block length
-				vec.push(0x01); // Identifies netscape looping extension
-				vec.extend_from_slice(&count.to_le_bytes());
-			} 
-		}
+        match ext {
+            Extension::GraphicControl(gc) => {
+                vec.push(0xF9); // Graphic control label
+                vec.push(0x04); // Block size for this extension is always 4
+                vec.push(gc.packed);
+                vec.extend_from_slice(&gc.delay_time.to_le_bytes());
+                vec.push(gc.transparency_index);
+            }
+            Extension::Looping(count) => {
+                vec.push(0xFF); // Application extension label
+                vec.push(0x0B); // 11 bytes in this block
+                vec.extend_from_slice(b"NETSCAPE2.0"); // App. ident. and "auth code"
+                vec.push(0x03); // Sub-block length
+                vec.push(0x01); // Identifies netscape looping extension
+                vec.extend_from_slice(&count.to_le_bytes());
+            }
+            Extension::Comment(_) => todo!(),
+            Extension::Application(_) => todo!(),
+        }
 
-		vec.push(0x00); // Zero-length data block indicates end of extension
-		vec.into_boxed_slice()
-	}
-}
\ No newline at end of file
+        vec.push(0x00); // Zero-length data block indicates end of extension
+        vec.into_boxed_slice()
+    }
+}
diff --git a/src/block/imagedescriptor.rs b/src/block/imagedescriptor.rs
index c911baa..415bee7 100644
--- a/src/block/imagedescriptor.rs
+++ b/src/block/imagedescriptor.rs
@@ -1,45 +1,73 @@
+use std::convert::TryInto;
+
 pub struct ImageDescriptor {
-	// Image Seperator 0x2C is the first byte //
-	pub left: u16,
-	pub top: u16,
-	pub width: u16,
-	pub height: u16,
-	pub packed: u8
+    // Image Seperator 0x2C is the first byte //
+    pub left: u16,
+    pub top: u16,
+    pub width: u16,
+    pub height: u16,
+    pub packed: u8,
 }
 
 impl ImageDescriptor {
-	pub fn color_table_present(&mut self, is_present: bool) {
-		if is_present {
-			self.packed |= 0b1000_0000;
-		} else {
-			self.packed &= 0b0111_1111;
-		}
-	}
-
-	pub fn color_table_size(&mut self, size: u8) {
-		// GCT size is calulated by raising two to this number plus one,
-		// so we have to work backwards.
-		let size = (size as f32).log2().ceil() - 1f32;
-		self.packed |= size as u8;
-	}
-
-	//TODO: Setter for sort flag in packed field
-	//TODO: Setter for interlace flag in packed field
+    pub fn set_color_table_present(&mut self, is_present: bool) {
+        if is_present {
+            self.packed |= 0b1000_0000;
+        } else {
+            self.packed &= 0b0111_1111;
+        }
+    }
+
+    pub fn set_color_table_size(&mut self, size: u8) {
+        // GCT size is calulated by raising two to this number plus one,
+        // so we have to work backwards.
+        let size = (size as f32).log2().ceil() - 1f32;
+        self.packed |= size as u8;
+    }
+
+    //TODO: Setter for sort flag in packed field
+    //TODO: Setter for interlace flag in packed field
+
+    pub fn color_table_present(&self) -> bool {
+        self.packed & 0b1000_0000 != 0
+    }
+
+    pub fn color_table_size(&self) -> usize {
+        crate::packed_to_color_table_length(self.packed & 0b0000_0111)
+    }
 }
 
 impl From<&ImageDescriptor> for Box<[u8]> {
-	fn from(desc: &ImageDescriptor) -> Self {
-		let mut vec = vec![];
-
-		vec.push(0x2C); // Image Seperator
-		vec.extend_from_slice(&desc.left.to_le_bytes());
-		vec.extend_from_slice(&desc.top.to_le_bytes());
-		vec.extend_from_slice(&desc.width.to_le_bytes());
-		vec.extend_from_slice(&desc.height.to_le_bytes());
-		vec.push(desc.packed);
-
-		vec.into_boxed_slice()
-	}
+    fn from(desc: &ImageDescriptor) -> Self {
+        let mut vec = vec![];
+
+        vec.push(0x2C); // Image Seperator
+        vec.extend_from_slice(&desc.left.to_le_bytes());
+        vec.extend_from_slice(&desc.top.to_le_bytes());
+        vec.extend_from_slice(&desc.width.to_le_bytes());
+        vec.extend_from_slice(&desc.height.to_le_bytes());
+        vec.push(desc.packed);
+
+        vec.into_boxed_slice()
+    }
+}
+
+impl From<[u8; 9]> for ImageDescriptor {
+    fn from(arr: [u8; 9]) -> Self {
+        let left = u16::from_le_bytes(arr[0..2].try_into().unwrap());
+        let top = u16::from_le_bytes(arr[2..4].try_into().unwrap());
+        let width = u16::from_le_bytes(arr[4..6].try_into().unwrap());
+        let height = u16::from_le_bytes(arr[6..8].try_into().unwrap());
+        let packed = arr[8];
+
+        Self {
+            left,
+            top,
+            width,
+            height,
+            packed,
+        }
+    }
 }
 
-//TODO: Impl to allow changing the packed field easier
\ No newline at end of file
+//TODO: Impl to allow changing the packed field easier
diff --git a/src/block/indexedimage.rs b/src/block/indexedimage.rs
index ae2da06..52be3d5 100644
--- a/src/block/indexedimage.rs
+++ b/src/block/indexedimage.rs
@@ -1,45 +1,54 @@
-use crate::LZW;
+use std::convert::TryFrom;
+
 use super::{ColorTable, ImageDescriptor};
+use crate::LZW;
 
 pub struct IndexedImage {
-	pub image_descriptor: ImageDescriptor,
-	pub local_color_table: Option<ColorTable>,
-	pub indicies: Vec<u8>
+    pub image_descriptor: ImageDescriptor,
+    pub local_color_table: Option<ColorTable>,
+    pub indicies: Vec<u8>,
 }
 
 impl IndexedImage {
-	pub fn as_boxed_slice(&self, minimum_code_size: u8) -> Box<[u8]> {
-		let mut out = vec![];
-
-		let mut boxed: Box<[u8]> = (&self.image_descriptor).into();
-		out.extend_from_slice(&*boxed);
-
-		// Get the mcs while we write out the color table
-		let mut mcs = if let Some(lct) = &self.local_color_table {
-			boxed = lct.into();
-			out.extend_from_slice(&*boxed);
-
-			lct.packed_len()
-		} else {
-			minimum_code_size
-		};
-
-		if mcs < 2 {
-			mcs = 2; // Must be true: 0 <= mcs <= 8
-		}
-
-		// First write out the MCS
-		out.push(mcs);
-
-		let compressed = LZW::encode(mcs, &self.indicies);
-		
-		for chunk in compressed.chunks(255) {
-			out.push(chunk.len() as u8);
-			out.extend_from_slice(chunk);
-		}
-		// Data block length 0 to indicate an end
-		out.push(0x00);
-
-		out.into_boxed_slice()
-	}
-}
\ No newline at end of file
+    pub fn as_boxed_slice(&self, minimum_code_size: u8) -> Box<[u8]> {
+        let mut out = vec![];
+
+        let mut boxed: Box<[u8]> = (&self.image_descriptor).into();
+        out.extend_from_slice(&*boxed);
+
+        // Get the mcs while we write out the color table
+        let mut mcs = if let Some(lct) = &self.local_color_table {
+            boxed = lct.into();
+            out.extend_from_slice(&*boxed);
+
+            lct.packed_len()
+        } else {
+            minimum_code_size + 1
+        };
+
+        if mcs < 2 {
+            mcs = 2; // Must be true: 0 <= mcs <= 8
+        }
+
+        // First write out the MCS
+        out.push(mcs);
+
+        let compressed = LZW::encode(mcs, &self.indicies);
+
+        for chunk in compressed.chunks(255) {
+            out.push(chunk.len() as u8);
+            out.extend_from_slice(chunk);
+        }
+        // Data block length 0 to indicate an end
+        out.push(0x00);
+
+        out.into_boxed_slice()
+    }
+}
+
+pub struct BlockedImage {
+    pub image_descriptor: ImageDescriptor,
+    pub local_color_table: Option<ColorTable>,
+    pub lzw_minimum_code_size: u8,
+    pub blocks: Vec<Vec<u8>>,
+}
diff --git a/src/block/mod.rs b/src/block/mod.rs
index 38b10ea..e3136bf 100644
--- a/src/block/mod.rs
+++ b/src/block/mod.rs
@@ -1,17 +1,19 @@
 mod colortable;
 pub mod extension;
-mod indexedimage;
 mod imagedescriptor;
+mod indexedimage;
 mod screendescriptor;
 mod version;
 
 pub use colortable::ColorTable;
-pub use indexedimage::IndexedImage;
 pub use imagedescriptor::ImageDescriptor;
+pub use indexedimage::BlockedImage;
+pub use indexedimage::IndexedImage;
 pub use screendescriptor::ScreenDescriptor;
 pub use version::Version;
 
 pub enum Block {
-	IndexedImage(IndexedImage),
-	Extension(extension::Extension)
-}
\ No newline at end of file
+    IndexedImage(IndexedImage),
+    BlockedImage(BlockedImage),
+    Extension(extension::Extension),
+}
diff --git a/src/block/screendescriptor.rs b/src/block/screendescriptor.rs
index d53d252..ff70896 100644
--- a/src/block/screendescriptor.rs
+++ b/src/block/screendescriptor.rs
@@ -1,40 +1,69 @@
+use std::convert::TryInto;
+
 pub struct ScreenDescriptor {
-	pub width: u16,
-	pub height: u16,
-	pub packed: u8,
-	pub background_color_index: u8,
-	pub pixel_aspect_ratio: u8
+    pub width: u16,
+    pub height: u16,
+    pub packed: u8,
+    pub background_color_index: u8,
+    pub pixel_aspect_ratio: u8,
 }
 
 impl ScreenDescriptor {
-	pub fn color_table_present(&mut self, is_present: bool) {
-		if is_present {
-			self.packed |= 0b1000_0000;
-		} else {
-			self.packed &= 0b0111_1111;
-		}
-	}
-
-	pub fn color_table_size(&mut self, size: u8) {
-		// GCT size is calulated by raising two to this number plus one,
-		// so we have to work backwards.
-		let size = (size as f32).log2().ceil() - 1f32;
-		self.packed |= size as u8;
-	}
-
-	//TODO: Setter for sort flag in packed field
-	//TODO: Setter for color resolution in packed field
+    pub fn set_color_table_present(&mut self, is_present: bool) {
+        if is_present {
+            self.packed |= 0b1000_0000;
+        } else {
+            self.packed &= 0b0111_1111;
+        }
+    }
+
+    pub fn set_color_table_size(&mut self, size: u8) {
+        println!("scts: {}", size);
+        // GCT size is calulated by raising two to this number plus one,
+        // so we have to work backwards.
+        let size = (size as f32).log2().ceil() - 1f32;
+        self.packed |= size as u8;
+    }
+
+    //TODO: Setter for sort flag in packed field
+    //TODO: Setter for color resolution in packed field
+
+    pub fn color_table_present(&self) -> bool {
+        self.packed & 0b1000_0000 != 0
+    }
+
+    pub fn color_table_len(&self) -> usize {
+        crate::packed_to_color_table_length(self.packed & 0b0000_0111)
+    }
 }
 
 impl From<&ScreenDescriptor> for Box<[u8]> {
-	fn from(lsd: &ScreenDescriptor) -> Self {
-		let mut vec = vec![];
-		vec.extend_from_slice(&lsd.width.to_le_bytes());
-		vec.extend_from_slice(&lsd.height.to_le_bytes());
-		vec.push(lsd.packed);
-		vec.push(lsd.background_color_index);
-		vec.push(lsd.pixel_aspect_ratio);
-
-		vec.into_boxed_slice()
-	}
-}
\ No newline at end of file
+    fn from(lsd: &ScreenDescriptor) -> Self {
+        let mut vec = vec![];
+        vec.extend_from_slice(&lsd.width.to_le_bytes());
+        vec.extend_from_slice(&lsd.height.to_le_bytes());
+        vec.push(lsd.packed);
+        vec.push(lsd.background_color_index);
+        vec.push(lsd.pixel_aspect_ratio);
+
+        vec.into_boxed_slice()
+    }
+}
+
+impl From<[u8; 7]> for ScreenDescriptor {
+    fn from(arr: [u8; 7]) -> Self {
+        let width = u16::from_le_bytes(arr[0..2].try_into().unwrap());
+        let height = u16::from_le_bytes(arr[2..4].try_into().unwrap());
+        let packed = arr[4];
+        let background_color_index = arr[5];
+        let pixel_aspect_ratio = arr[6];
+
+        Self {
+            width,
+            height,
+            packed,
+            background_color_index,
+            pixel_aspect_ratio,
+        }
+    }
+}
diff --git a/src/block/version.rs b/src/block/version.rs
index a5d688d..b785f27 100644
--- a/src/block/version.rs
+++ b/src/block/version.rs
@@ -1,13 +1,24 @@
+use std::fmt;
+
 pub enum Version {
-	Gif87a,
-	Gif89a
+    Gif87a,
+    Gif89a,
 }
 
 impl From<&Version> for &[u8] {
-	fn from(version: &Version) -> Self {
-		match version {
-			Version::Gif87a => b"GIF87a",
-			Version::Gif89a => b"GIF89a"
-		}
-	}
-}
\ No newline at end of file
+    fn from(version: &Version) -> Self {
+        match version {
+            Version::Gif87a => b"GIF87a",
+            Version::Gif89a => b"GIF89a",
+        }
+    }
+}
+
+impl fmt::Display for Version {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Version::Gif87a => write!(f, "GIF87a"),
+            Version::Gif89a => write!(f, "GIF89a"),
+        }
+    }
+}
diff --git a/src/color.rs b/src/color.rs
index dc134ef..764acaf 100644
--- a/src/color.rs
+++ b/src/color.rs
@@ -1,11 +1,22 @@
+#[derive(Copy, Clone, Debug)]
 pub struct Color {
-	pub r: u8,
-	pub g: u8,
-	pub b: u8
+    pub r: u8,
+    pub g: u8,
+    pub b: u8,
 }
 
 impl Color {
-	pub fn new(r: u8, g: u8, b: u8) -> Self {
-		Self { r, g, b }
-	}
-}
\ No newline at end of file
+    pub fn new(r: u8, g: u8, b: u8) -> Self {
+        Self { r, g, b }
+    }
+}
+
+impl From<[u8; 3]> for Color {
+    fn from(arr: [u8; 3]) -> Self {
+        Self {
+            r: arr[0],
+            g: arr[1],
+            b: arr[2],
+        }
+    }
+}
diff --git a/src/gif.rs b/src/gif.rs
index e6ad70f..90564fc 100644
--- a/src/gif.rs
+++ b/src/gif.rs
@@ -1,126 +1,241 @@
-use crate::block::{Block, ColorTable, extension::Extension, ScreenDescriptor, Version};
+use crate::block::{extension::Extension, Block, ColorTable, ScreenDescriptor, Version};
 pub struct Gif {
-	pub header: Version,
-	pub screen_descriptor: ScreenDescriptor,
-	pub global_color_table: Option<ColorTable>,
-	pub blocks: Vec<Block>
-	// Trailer at the end of this struct is 0x3B //
+    pub header: Version,
+    pub screen_descriptor: ScreenDescriptor,
+    pub global_color_table: Option<ColorTable>,
+    pub blocks: Vec<Block>, // Trailer at the end of this struct is 0x3B //
 }
 
 impl Gif {
-	pub fn to_vec(&self) -> Vec<u8> {
-		let mut out = vec![];
-
-		out.extend_from_slice((&self.header).into());
-		
-		let mut boxed: Box<[u8]> = (&self.screen_descriptor).into();
-		out.extend_from_slice(&*boxed);
-
-		// While we output the color table, grab it's length to use when
-		// outputting the image, or 0 if we don't have a GCT
-		let mcs = if let Some(gct) = &self.global_color_table {
-			boxed = gct.into();
-			out.extend_from_slice(&*boxed);
-
-			gct.packed_len()
-		} else {
-			0
-		};
-
-		for block in self.blocks.iter() {
-			match block {
-				Block::IndexedImage(image) => {
-					boxed = image.as_boxed_slice(mcs);
-					out.extend_from_slice(&*boxed);
-				},
-				Block::Extension(ext) => {
-					boxed = ext.into();
-					out.extend_from_slice(&*boxed);
-				}
-			}
-		}
-
-		// Write Trailer
-		out.push(0x3B);
-
-		out
-	}
+    pub fn to_vec(&self) -> Vec<u8> {
+        let mut out = vec![];
+
+        out.extend_from_slice((&self.header).into());
+
+        let mut boxed: Box<[u8]> = (&self.screen_descriptor).into();
+        out.extend_from_slice(&*boxed);
+
+        // While we output the color table, grab it's length to use when
+        // outputting the image, or 0 if we don't have a GCT
+        let mcs = if let Some(gct) = &self.global_color_table {
+            boxed = gct.into();
+            out.extend_from_slice(&*boxed);
+
+            gct.packed_len()
+        } else {
+            0
+        };
+
+        for block in self.blocks.iter() {
+            match block {
+                Block::IndexedImage(image) => {
+                    boxed = image.as_boxed_slice(mcs);
+                    out.extend_from_slice(&*boxed);
+                }
+                Block::BlockedImage(_) => unreachable!(),
+                Block::Extension(ext) => {
+                    boxed = ext.into();
+                    out.extend_from_slice(&*boxed);
+                }
+            }
+        }
+
+        // Write Trailer
+        out.push(0x3B);
+
+        out
+    }
 }
 
 #[cfg(test)]
 pub mod gif {
-	use crate::Color;
-	use crate::writer::{GifBuilder, ImageBuilder};
-	use crate::block::extension::{DisposalMethod, GraphicControl};
-	use super::*;
-
-	#[test]
-	fn to_vec_gif87a() {
-		let gct = vec![
-			Color::new(1, 2, 3), Color::new(253, 254, 255)
-		];
-		let colortable = vec![
-			Color::new(0, 0, 0), Color::new(128, 0, 255)
-		];
-		let indicies = vec![0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0];
-
-		let expected_out = vec![
-			0x47, 0x49, 0x46, 0x38, 0x37, 0x61, // Version - GIF87a
-			0x04, 0x00, 0x04, 0x00, 0b1000_0000, 0x00, 0x00, // Logical Screen Descriptor
-			1, 2, 3, 253, 254, 255, // Global Color Table
-			0x2C, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00, 0x04, 0x00, 0b1000_0000, // Image Descriptor 1
-			0, 0, 0, 128, 0, 255, // Color Table
-			0x02, 0x05, 0x84, 0x1D, 0x81, 0x7A, 0x50, 0x00, // Image Data 1
-			0x2C, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00, 0x04, 0x00, 0b0000_0000, // Image Descriptor 2
-			0x02, 0x05, 0x84, 0x1D, 0x81, 0x7A, 0x50, 0x00, // Image Data 2
-			0x3B // Trailer
-		];
-
-		let actual_out = GifBuilder::new(Version::Gif87a, 4, 4)
-			.global_color_table(gct.into())
-			.image(ImageBuilder::new(4, 4)
-				.color_table(colortable.into())
-				.indicies(indicies.clone())
-			).image(ImageBuilder::new(4, 4)
-				.indicies(indicies)
-			).build().to_vec();
-
-		assert_eq!(actual_out, expected_out);
-	}
-
-	#[test]
-	fn to_vec_gif89a() {
-		let gct = vec![
-			Color::new(1, 2, 3), Color::new(253, 254, 255)
-		];
-		let colortable = vec![
-			Color::new(0, 0, 0), Color::new(128, 0, 255)
-		];
-		let indicies = vec![0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0];
-
-		let expected_out = vec![
-			0x47, 0x49, 0x46, 0x38, 0x37, 0x61, // Version - GIF87a
-			0x04, 0x00, 0x04, 0x00, 0b1000_0000, 0x00, 0x00, // Logical Screen Descriptor
-			1, 2, 3, 253, 254, 255, // Global Color Table
-			0x2C, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00, 0x04, 0x00, 0b1000_0000, // Image Descriptor 1
-			0, 0, 0, 128, 0, 255, // Color Table
-			0x02, 0x05, 0x84, 0x1D, 0x81, 0x7A, 0x50, 0x00, // Image Data 1
-			0x21, 0xF9, 0x04, 0b000_010_0_0, 0x40, 0x00, 0x00, 0x00, // Graphic Control Extension
-			0x2C, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00, 0x04, 0x00, 0b0000_0000, // Image Descriptor 2
-			0x02, 0x05, 0x84, 0x1D, 0x81, 0x7A, 0x50, 0x00, // Image Data 2
-			0x3B // Trailer
-		];
-
-		let actual_out = GifBuilder::new(Version::Gif87a, 4, 4)
-			.global_color_table(gct.into())
-			.image(ImageBuilder::new(4, 4)
-				.color_table(colortable.into())
-				.indicies(indicies.clone())
-			).extension(Extension::GraphicControl(GraphicControl::new(DisposalMethod::RestoreBackground, false, false, 64, 0)))
-			.image(ImageBuilder::new(4, 4)
-				.indicies(indicies)
-			).build().to_vec();
-
-		assert_eq!(actual_out, expected_out);
-	}
-}
\ No newline at end of file
+    use super::*;
+    use crate::block::extension::{DisposalMethod, GraphicControl};
+    use crate::writer::{GifBuilder, ImageBuilder};
+    use crate::Color;
+
+    #[test]
+    fn to_vec_gif87a() {
+        let gct = vec![Color::new(1, 2, 3), Color::new(253, 254, 255)];
+        let colortable = vec![Color::new(0, 0, 0), Color::new(128, 0, 255)];
+        let indicies = vec![0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0];
+
+        let expected_out = vec![
+            0x47,
+            0x49,
+            0x46,
+            0x38,
+            0x37,
+            0x61, // Version - GIF87a
+            0x04,
+            0x00,
+            0x04,
+            0x00,
+            0b1000_0000,
+            0x00,
+            0x00, // Logical Screen Descriptor
+            1,
+            2,
+            3,
+            253,
+            254,
+            255, // Global Color Table
+            0x2C,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x04,
+            0x00,
+            0x04,
+            0x00,
+            0b1000_0000, // Image Descriptor 1
+            0,
+            0,
+            0,
+            128,
+            0,
+            255, // Color Table
+            0x02,
+            0x05,
+            0x84,
+            0x1D,
+            0x81,
+            0x7A,
+            0x50,
+            0x00, // Image Data 1
+            0x2C,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x04,
+            0x00,
+            0x04,
+            0x00,
+            0b0000_0000, // Image Descriptor 2
+            0x02,
+            0x05,
+            0x84,
+            0x1D,
+            0x81,
+            0x7A,
+            0x50,
+            0x00, // Image Data 2
+            0x3B, // Trailer
+        ];
+
+        let actual_out = GifBuilder::new(Version::Gif87a, 4, 4)
+            .global_color_table(gct.into())
+            .image(
+                ImageBuilder::new(4, 4)
+                    .color_table(colortable.into())
+                    .indicies(indicies.clone()),
+            )
+            .image(ImageBuilder::new(4, 4).indicies(indicies))
+            .build()
+            .to_vec();
+
+        assert_eq!(actual_out, expected_out);
+    }
+
+    #[test]
+    fn to_vec_gif89a() {
+        let gct = vec![Color::new(1, 2, 3), Color::new(253, 254, 255)];
+        let colortable = vec![Color::new(0, 0, 0), Color::new(128, 0, 255)];
+        let indicies = vec![0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0];
+
+        let expected_out = vec![
+            0x47,
+            0x49,
+            0x46,
+            0x38,
+            0x37,
+            0x61, // Version - GIF87a
+            0x04,
+            0x00,
+            0x04,
+            0x00,
+            0b1000_0000,
+            0x00,
+            0x00, // Logical Screen Descriptor
+            1,
+            2,
+            3,
+            253,
+            254,
+            255, // Global Color Table
+            0x2C,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x04,
+            0x00,
+            0x04,
+            0x00,
+            0b1000_0000, // Image Descriptor 1
+            0,
+            0,
+            0,
+            128,
+            0,
+            255, // Color Table
+            0x02,
+            0x05,
+            0x84,
+            0x1D,
+            0x81,
+            0x7A,
+            0x50,
+            0x00, // Image Data 1
+            0x21,
+            0xF9,
+            0x04,
+            0b000_010_0_0,
+            0x40,
+            0x00,
+            0x00,
+            0x00, // Graphic Control Extension
+            0x2C,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x04,
+            0x00,
+            0x04,
+            0x00,
+            0b0000_0000, // Image Descriptor 2
+            0x02,
+            0x05,
+            0x84,
+            0x1D,
+            0x81,
+            0x7A,
+            0x50,
+            0x00, // Image Data 2
+            0x3B, // Trailer
+        ];
+
+        let actual_out = GifBuilder::new(Version::Gif87a, 4, 4)
+            .global_color_table(gct.into())
+            .image(
+                ImageBuilder::new(4, 4)
+                    .color_table(colortable.into())
+                    .indicies(indicies.clone()),
+            )
+            .extension(Extension::GraphicControl(GraphicControl::new(
+                DisposalMethod::RestoreBackground,
+                false,
+                false,
+                64,
+                0,
+            )))
+            .image(ImageBuilder::new(4, 4).indicies(indicies))
+            .build()
+            .to_vec();
+
+        assert_eq!(actual_out, expected_out);
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
index 83b0b77..6c0203c 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -3,13 +3,20 @@ mod gif;
 mod lzw;
 
 pub mod block;
+pub mod reader;
 pub mod writer;
 
 pub use color::Color;
 pub use gif::Gif;
 pub use lzw::LZW;
 
+/// Perform the algorithm to get the length of a color table from
+/// the value of the packed field. The max value here is 256
+pub(crate) fn packed_to_color_table_length(packed: u8) -> usize {
+    2usize.pow(packed as u32 + 1)
+}
+
 //TODO: Be sure to check that fields in LSD and Img. Desc. that were reserved
 //in 87a aren't set if version is 87a, or that we return a warning, etc. Just
 //remember about this.
-//bottom of page 24 in 89a
\ No newline at end of file
+//bottom of page 24 in 89a
diff --git a/src/lzw.rs b/src/lzw.rs
index 1970617..053c5c4 100644
--- a/src/lzw.rs
+++ b/src/lzw.rs
@@ -2,174 +2,172 @@ use std::collections::HashMap;
 
 pub struct LZW {}
 impl LZW {
-	//TODO: Cleanup and make not awful
-	pub fn encode(minimum_size: u8, indicies: &[u8]) -> Vec<u8> {
-		let mut dictionary: HashMap<Vec<u8>, u16> = HashMap::new();
-
-		let cc: u16 = 2u16.pow(minimum_size as u32);
-		let eoi: u16 = cc+1;
-
-		let mut index: u16 = eoi+1; // Next code number
-		let mut codesize: u8 = minimum_size+1; // Current code size
-
-		//println!("cc: {} - eoi: {}", cc, eoi);
-
-		// Populate starting codes
-		for code in 0..cc {
-			dictionary.insert(vec![code as u8], code);
-		}
-
-		let mut iter = indicies.iter();
-		let mut out = BitStream::new();
-		let mut buffer = vec![*iter.next().unwrap()]; //TODO: Remove unwrap
-
-		//"Encoders should output a Clear code as the first code of each image data stream."
-		out.push_bits(codesize, cc);
-
-		//println!("Before Loop\n\tBuffer: {:?}\n\tCodesize:{}\n\tIndex:{}", buffer, codesize, index);
-
-		for next_code in iter {
-			buffer.push(*next_code);
-
-			//println!("Buffer: {:?} - Codesize:{} - Index:{}\n\tDict: {:?}", buffer, codesize, index, dictionary);
-
-			match dictionary.get(&buffer) {
-				Some(_code) => {
-					//println!("\tPresent!");
-					continue;
-				},
-				None => {
-					buffer.pop();
-					match dictionary.get(&buffer) {
-						Some(code) => {
-							out.push_bits(codesize, *code);
-							//println!("\tOutputting {} with {} bits. Buffer is {:?}", *code, codesize, buffer);
-
-							// Add new entry for buffer and increase the index
-							buffer.push(*next_code);
-							dictionary.insert(buffer, index);
-							index += 1;
-
-							// Increase code size if we should
-							if index-1 == 2u16.pow(codesize as u32) {
-								codesize += 1;
-							}
-
-							// Reset the buffer to only contain next_code
-							buffer = vec![*next_code];
-						},
-						None => panic!("No dictionary entry when there should be! Something is wrong!")
-					}
-				}
-			}
-		}
-
-		if buffer.len() > 0 {
-			match dictionary.get(&buffer) {
-				None => panic!("No codes left but not in the dictionary!"),
-				Some(code) => out.push_bits(codesize, *code)
-			}
-		}
-		out.push_bits(codesize, eoi);
-
-		out.vec()
-	}
+    pub fn encode(minimum_size: u8, indicies: &[u8]) -> Vec<u8> {
+        let mut dictionary: HashMap<Vec<u8>, u16> = HashMap::new();
+
+        let cc = 2u16.pow(minimum_size as u32);
+        let eoi = cc + 1;
+
+        // Fill dictionary with self-descriptive values
+        for value in 0..cc {
+            dictionary.insert(vec![value as u8], value);
+        }
+
+        let mut next_code = eoi + 1;
+        let mut code_size = minimum_size + 1;
+
+        let mut iter = indicies.into_iter();
+        let mut out = BitStream::new();
+        let mut buffer = vec![*iter.next().unwrap()];
+
+        out.push_bits(code_size, cc);
+
+        for &indicie in iter {
+            buffer.push(indicie);
+
+            if !dictionary.contains_key(&buffer) {
+                buffer.pop();
+
+                if let Some(&code) = dictionary.get(&buffer) {
+                    out.push_bits(code_size, code);
+
+                    // Put the code back and add the vec to the dict
+                    buffer.push(indicie);
+                    dictionary.insert(buffer.clone(), next_code);
+                    next_code += 1;
+
+                    // If the next_code can't fit in the code_size, we have to increase it
+                    if next_code - 1 == 2u16.pow(code_size as u32) {
+                        code_size += 1;
+                    }
+
+                    buffer.clear();
+                    buffer.push(indicie);
+                } else {
+                    unreachable!()
+                }
+            }
+        }
+
+        if buffer.len() > 0 {
+            match dictionary.get(&buffer) {
+                Some(&code) => out.push_bits(code_size, code),
+                None => {
+                    panic!("Codes left in the buffer but the buffer is not a valid dictionary key!")
+                }
+            }
+        }
+        out.push_bits(code_size, eoi);
+
+        out.vec()
+    }
 }
 
 #[cfg(test)]
 mod lzw_test {
-	use super::*;
+    use super::*;
 
-	#[test]
-	fn encode() {
-		let indicies = vec![0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0];
-		let output = vec![0x84, 0x1D, 0x81, 0x7A, 0x50];
+    #[test]
+    fn encode() {
+        let indicies = vec![0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0];
+        let output = vec![0x84, 0x1D, 0x81, 0x7A, 0x50];
 
-		let lzout = LZW::encode(2, &indicies);
+        let lzout = LZW::encode(2, &indicies);
 
-		assert_eq!(lzout, output);
-	}
+        assert_eq!(lzout, output);
+    }
+
+    #[test]
+    fn against_weezl() {
+        let indicies = vec![0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0];
+        let weezl = weezl::encode::Encoder::new(weezl::BitOrder::Lsb, 2)
+            .encode(&indicies)
+            .unwrap();
+        let us = LZW::encode(2, &indicies);
+
+        assert_eq!(weezl, us);
+    }
 }
 
 struct BitStream {
-	formed: Vec<u8>,
-	current: u8,
-	index: u8
+    formed: Vec<u8>,
+    current: u8,
+    index: u8,
 }
 
 impl BitStream {
-	fn new() -> Self {
-		Self {
-			formed: vec![],
-			current: 0,
-			index: 0
-		}
-	}
-
-	fn push_bits(&mut self, count: u8, data: u16) {
-		let mut new_index = self.index + count;
-		let mut current32 = (self.current as u32) | ((data as u32) << self.index);
-
-		loop {
-			if new_index >= 8 {
-				self.formed.push(current32 as u8);
-				current32 = current32 >> 8;
-				new_index -= 8;
-			} else {
-				self.current = current32 as u8;
-				self.index = new_index;
-
-				break;
-			}
-		}
-	}
-
-	fn vec(self) -> Vec<u8> {
-		let mut out = self.formed;
-
-		if self.index != 0 {
-			out.push(self.current);
-		}
-
-		out
-	}
+    fn new() -> Self {
+        Self {
+            formed: vec![],
+            current: 0,
+            index: 0,
+        }
+    }
+
+    fn push_bits(&mut self, count: u8, data: u16) {
+        let mut new_index = self.index + count;
+        let mut current32 = (self.current as u32) | ((data as u32) << self.index);
+
+        loop {
+            if new_index >= 8 {
+                self.formed.push(current32 as u8);
+                current32 = current32 >> 8;
+                new_index -= 8;
+            } else {
+                self.current = current32 as u8;
+                self.index = new_index;
+
+                break;
+            }
+        }
+    }
+
+    fn vec(self) -> Vec<u8> {
+        let mut out = self.formed;
+
+        if self.index != 0 {
+            out.push(self.current);
+        }
+
+        out
+    }
 }
 
 #[cfg(test)]
 mod bitstream_test {
-	use super::*;
-
-	#[test]
-	fn short_push() {
-		let mut bs = BitStream::new();
-		bs.push_bits(2, 3);
-		bs.push_bits(2, 3);
-		bs.push_bits(3, 1);
-		bs.push_bits(2, 3);
-
-		let bsvec = bs.vec();
-
-		for byte in &bsvec {
-			print!("{:b} ", byte);
-		}
-		println!("");
-
-		assert_eq!(bsvec, vec![0b1001_1111, 0b0000_0001]);
-	}
-
-	#[test]
-	fn long_push() {
-		let mut bs = BitStream::new();
-		bs.push_bits(1, 1);
-		bs.push_bits(12, 2049);
-
-		let bsvec = bs.vec();
-
-		for byte in &bsvec {
-			print!("{:b} ", byte);
-		}
-		println!("");
-
-		assert_eq!(bsvec, vec![0b0000_0011, 0b0001_0000]);
-	}
-}
\ No newline at end of file
+    use super::*;
+
+    #[test]
+    fn short_push() {
+        let mut bs = BitStream::new();
+        bs.push_bits(2, 3);
+        bs.push_bits(2, 3);
+        bs.push_bits(3, 1);
+        bs.push_bits(2, 3);
+
+        let bsvec = bs.vec();
+
+        for byte in &bsvec {
+            print!("{:b} ", byte);
+        }
+        println!("");
+
+        assert_eq!(bsvec, vec![0b1001_1111, 0b0000_0001]);
+    }
+
+    #[test]
+    fn long_push() {
+        let mut bs = BitStream::new();
+        bs.push_bits(1, 1);
+        bs.push_bits(12, 2049);
+
+        let bsvec = bs.vec();
+
+        for byte in &bsvec {
+            print!("{:b} ", byte);
+        }
+        println!("");
+
+        assert_eq!(bsvec, vec![0b0000_0011, 0b0001_0000]);
+    }
+}
diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 0000000..269470a
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,195 @@
+use std::{fs::File, io::Write};
+
+use gifed::{
+    block::{
+        extension::{Extension, GraphicControl},
+        BlockedImage, ColorTable, Version,
+    },
+    reader::GifReader,
+    writer::{GifBuilder, ImageBuilder},
+    Color,
+};
+use owo_colors::OwoColorize;
+
+fn main() {
+    write_test();
+    //return;
+    let gif = GifReader::file("test.gif");
+    //let gif = GifReader::file("/home/gen/Downloads/tas_tillie.gif");
+
+    println!("Version {}", gif.header.yellow());
+    println!(
+        "Logical Screen Descriptor\n\tDimensions {}x{}",
+        gif.screen_descriptor.width.yellow(),
+        gif.screen_descriptor.height.yellow()
+    );
+
+    if gif.screen_descriptor.color_table_present() {
+        println!(
+            "\tGlobal Color Table Present {}\n\tGlobal Color Table Size {}",
+            "Yes".green(),
+            gif.screen_descriptor.color_table_len().green()
+        );
+    } else {
+        println!(
+            "\tGlobal Color Table Present {}\n\tGlobal Color Table Size {}",
+            "No".red(),
+            gif.screen_descriptor.color_table_len().red()
+        );
+    }
+
+    for block in gif.blocks {
+        match block {
+            gifed::block::Block::IndexedImage(_) => todo!(),
+            gifed::block::Block::BlockedImage(bli) => describe_blocked_image(bli),
+            gifed::block::Block::Extension(ext) => match ext {
+                gifed::block::extension::Extension::GraphicControl(gce) => {
+                    println!(
+                        "Graphic Control Extension\n\tDelay Time {}",
+                        format!("{}s", gce.delay_time() as f32 / 100.0).yellow()
+                    )
+                }
+                gifed::block::extension::Extension::Looping(_) => todo!(),
+                gifed::block::extension::Extension::Comment(cmt) => {
+                    println!("Comment Extension\n\tLength {}", cmt.len())
+                }
+                gifed::block::extension::Extension::Application(app) => {
+                    let auth = app.authentication_code();
+                    println!("Application Extension\n\tIdentifier {}\n\tAuthentication {:02X} {:02X} {:02X}",app.identifier().yellow(), auth[0].yellow(), auth[1].yellow(), auth[2].yellow());
+                }
+            },
+        }
+    }
+}
+
+fn describe_blocked_image(bli: BlockedImage) {
+    println!(
+        "Image\n\tOffset {}x{}\n\tDimensions {}x{}",
+        bli.image_descriptor.left.yellow(),
+        bli.image_descriptor.top.yellow(),
+        bli.image_descriptor.width.yellow(),
+        bli.image_descriptor.height.yellow(),
+    );
+
+    if bli.image_descriptor.color_table_present() {
+        println!(
+            "\tLocal Color Table Present {}\n\tLocal Color Table Size {}",
+            "Yes".green(),
+            bli.image_descriptor.color_table_size().green()
+        );
+    } else {
+        println!(
+            "\tLocal Color Table Present {}\n\tLocal Color Table Size {}",
+            "No".red(),
+            bli.image_descriptor.color_table_size().red()
+        );
+    }
+
+    println!(
+        "\t{} image data sub-blocks totaling {} bytes",
+        bli.blocks.len().yellow(),
+        bli.blocks
+            .iter()
+            .map(|vec| vec.len())
+            .sum::<usize>()
+            .yellow()
+    )
+}
+
+fn write_test() {
+    const size: u16 = 256;
+    let gcon = GraphicControl::new(
+        gifed::block::extension::DisposalMethod::Clear,
+        false,
+        false,
+        25,
+        0,
+    );
+
+    let mut gct = ColorTable::new();
+    gct.push(Color {
+        r: 0x44,
+        g: 0x44,
+        b: 0x44,
+    });
+    gct.push(Color {
+        r: 0x88,
+        g: 0x44,
+        b: 0xDD,
+    });
+
+    println!("{} {}", gct.packed_len(), gct.len());
+
+    let mut builder = GifBuilder::new(Version::Gif89a, size, size).global_color_table(gct);
+
+    for x in 4..16 {
+        let mut raw = vec![0; size as usize * size as usize];
+
+        for i in x * 7..x * 7 + 32 {
+            for j in x * 7..x * 7 + 32 {
+                let index = i * size as usize + j;
+                raw[index as usize] = 1;
+            }
+        }
+
+        builder = builder
+            .extension(Extension::GraphicControl(gcon.clone()))
+            .image(ImageBuilder::new(size, size).indicies(raw));
+    }
+
+    builder = builder.extension(Extension::Looping(0));
+
+    let vec = builder.build().to_vec();
+    File::create("test.gif").unwrap().write_all(&vec).unwrap();
+
+    let mut text_gif = File::create("test_gif.txt").unwrap();
+    for byte in vec {
+        text_gif
+            .write_all(&format!("{:02X} ", byte).as_bytes())
+            .unwrap();
+    }
+}
+
+fn write_static_test() {
+    const size: u16 = 256;
+
+    let mut gct = ColorTable::new();
+    gct.push(Color {
+        r: 0x44,
+        g: 0x44,
+        b: 0x44,
+    });
+    gct.push(Color {
+        r: 0x55,
+        g: 0x44,
+        b: 0x88,
+    });
+
+    println!("{} {}", gct.packed_len(), gct.len());
+
+    let mut builder = GifBuilder::new(Version::Gif87a, size, size).global_color_table(gct);
+
+    let x = 4;
+    let mut raw = vec![0; size as usize * size as usize];
+
+    for i in x * 7..x * 7 + 8 {
+        for j in x * 7..x * 7 + 8 {
+            let index = i * size as usize + j;
+            raw[index as usize] = 1;
+        }
+    }
+
+    builder = builder.image(ImageBuilder::new(size, size).indicies(raw));
+
+    //builder = builder.extension(Extension::Looping(0));
+
+    let vec = builder.build().to_vec();
+    File::create("test.gif").unwrap().write_all(&vec).unwrap();
+
+    let mut text_gif = File::create("test_gif.txt").unwrap();
+    for byte in vec {
+        text_gif
+            .write_all(&format!("{:02X} ", byte).as_bytes())
+            .unwrap();
+    }
+}
diff --git a/src/reader/mod.rs b/src/reader/mod.rs
new file mode 100644
index 0000000..606de11
--- /dev/null
+++ b/src/reader/mod.rs
@@ -0,0 +1,239 @@
+use std::{
+    borrow::Cow,
+    convert::{TryFrom, TryInto},
+    fs::File,
+    io::{BufRead, BufReader, Read},
+    path::Path,
+};
+
+use crate::{
+    block::{
+        extension::{Application, Extension, GraphicControl},
+        Block, BlockedImage, ColorTable, ImageDescriptor, ScreenDescriptor, Version,
+    },
+    Gif,
+};
+
+pub struct GifReader {}
+
+impl GifReader {
+    pub fn file<P: AsRef<Path>>(path: P) -> Gif {
+        let mut file = File::open(path).expect("Failed to open file");
+        let mut reader = SmartReader {
+            inner: vec![],
+            position: 0,
+        };
+        file.read_to_end(&mut reader.inner)
+            .expect("Failed to read gif");
+
+        let mut gif = Self::read_required(&mut reader);
+
+        if gif.screen_descriptor.color_table_present() {
+            let gct_size = gif.screen_descriptor.color_table_len() * 3;
+            gif.global_color_table = Some(Self::read_color_table(&mut reader, gct_size));
+        }
+
+        loop {
+            match Self::read_block(&mut reader) {
+                Some(block) => {
+                    /*match &block {
+                        Block::IndexedImage(_) => println!("Indexed Image"),
+                        Block::BlockedImage(_) => println!("Blocked Image"),
+                        Block::Extension(ext) => match ext {
+                            Extension::GraphicControl(_) => println!("Graphic Cotrol Extension"),
+                            Extension::Looping(_) => println!("Netscape Extension"),
+                            Extension::Comment(vec) => {
+                                println!("Comment Extension {:X}", vec.len())
+                            }
+                            Extension::Application(_) => todo!(),
+                        },
+                    }*/
+
+                    gif.blocks.push(block)
+                }
+                None => return gif,
+            }
+        }
+    }
+
+    fn read_required(reader: &mut SmartReader) -> Gif {
+        let version = match reader.take_lossy_utf8(6).as_deref() {
+            Some("GIF87a") => Version::Gif87a,
+            Some("GIF89a") => Version::Gif89a,
+            _ => panic!("Version string is unknown"),
+        };
+
+        let mut lsd_buffer: [u8; 7] = [0; 7];
+        reader
+            .read_exact(&mut lsd_buffer)
+            .expect("Failed to read Logical Screen Descriptor from gif");
+
+        let lsd = ScreenDescriptor::from(lsd_buffer);
+
+        Gif {
+            header: version,
+            screen_descriptor: lsd,
+            global_color_table: None,
+            blocks: vec![],
+        }
+    }
+
+    fn read_color_table(reader: &mut SmartReader, size: usize) -> ColorTable {
+        let buffer = reader
+            .take(size as usize)
+            .expect("Failed to read Color Table");
+
+        ColorTable::try_from(&buffer[..]).expect("Failed to parse Color Table")
+    }
+
+    fn read_block(reader: &mut SmartReader) -> Option<Block> {
+        let block_id = reader.u8().expect("File ended early");
+
+        match block_id {
+            0x21 => Some(Self::read_extension(reader)),
+            0x2C => Some(Self::read_image(reader)),
+            0x3B => None,
+            _ => None, /*panic!(
+                           "Unknown block identifier {:X} {:X}",
+                           block_id, reader.position
+                       ),*/
+        }
+    }
+
+    fn read_extension(mut reader: &mut SmartReader) -> Block {
+        let mut extension_id = reader.u8().expect("File ended early");
+
+        match extension_id {
+            0xF9 => {
+                reader.skip(1); // Skip block length, we know it
+                let mut data = [0u8; 4];
+                reader
+                    .read_exact(&mut data)
+                    .expect("Data ended early in graphics control extension sublock");
+                reader.skip(1); // Skip block terminator
+
+                Block::Extension(Extension::GraphicControl(GraphicControl::from(data)))
+            }
+            0xFE => Block::Extension(Extension::Comment(reader.take_and_collapse_subblocks())),
+            0x01 => todo!(), // plain text extension
+            0xFF => {
+                assert_eq!(Some(11), reader.u8());
+                let identifier = reader.take_lossy_utf8(8).unwrap().to_string();
+                let authentication_code: [u8; 3] =
+                    TryInto::try_into(reader.take(3).unwrap()).unwrap();
+                let data = reader.take_and_collapse_subblocks();
+
+                Block::Extension(Extension::Application(Application {
+                    identifier,
+                    authentication_code,
+                    data,
+                }))
+            }
+            _ => panic!("Unknown Extension Identifier!"),
+        }
+    }
+
+    fn read_image(mut reader: &mut SmartReader) -> Block {
+        let mut buffer = [0u8; 9];
+        reader
+            .read_exact(&mut buffer)
+            .expect("Failed to read Image Descriptor");
+        let descriptor = ImageDescriptor::from(buffer);
+
+        let color_table = if descriptor.color_table_present() {
+            let size = descriptor.color_table_size() * 3;
+            Some(Self::read_color_table(&mut reader, size))
+        } else {
+            None
+        };
+
+        let lzw_csize = reader.u8().expect("Failed to read LZW Minimum Code Size");
+
+        let blocks = reader.take_data_subblocks();
+
+        Block::BlockedImage(BlockedImage {
+            image_descriptor: descriptor,
+            local_color_table: color_table,
+            lzw_minimum_code_size: lzw_csize,
+            blocks,
+        })
+    }
+}
+
+struct SmartReader {
+    inner: Vec<u8>,
+    position: usize,
+}
+
+impl SmartReader {
+    pub fn u8(&mut self) -> Option<u8> {
+        self.position += 1;
+        self.inner.get(self.position - 1).map(|b| *b)
+    }
+
+    pub fn u16(&mut self) -> Option<u16> {
+        self.position += 2;
+        self.inner
+            .get(self.position - 2..self.position)
+            .map(|bytes| u16::from_le_bytes(bytes.try_into().unwrap()))
+    }
+
+    pub fn skip(&mut self, size: usize) {
+        self.position += size;
+    }
+
+    pub fn take(&mut self, size: usize) -> Option<&[u8]> {
+        self.position += size;
+        self.inner.get(self.position - size..self.position)
+    }
+
+    //TODO: Result not Option when buffer len
+    pub fn read_exact(&mut self, buf: &mut [u8]) -> Option<()> {
+        if self.position + buf.len() > self.inner.len() {
+            None
+        } else {
+            self.position += buf.len();
+            buf.copy_from_slice(&self.inner[self.position - buf.len()..self.position]);
+            Some(())
+        }
+    }
+
+    pub fn take_vec(&mut self, size: usize) -> Option<Vec<u8>> {
+        self.position += size;
+        self.inner
+            .get(self.position - size..self.position)
+            .map(|bytes| bytes.to_vec())
+    }
+
+    pub fn take_lossy_utf8(&mut self, size: usize) -> Option<Cow<'_, str>> {
+        self.take(size).map(|bytes| String::from_utf8_lossy(bytes))
+    }
+
+    pub fn take_data_subblocks(&mut self) -> Vec<Vec<u8>> {
+        let mut blocks = vec![];
+
+        loop {
+            let block_size = self.u8().expect("Failed to read length of sublock");
+
+            if block_size == 0 {
+                return blocks;
+            }
+
+            let block = self
+                .take_vec(block_size as usize)
+                .expect("Failed to read sublock");
+
+            blocks.push(block);
+        }
+    }
+
+    pub fn take_and_collapse_subblocks(&mut self) -> Vec<u8> {
+        let blocks = self.take_data_subblocks();
+        let mut ret = vec![];
+        for block in blocks {
+            ret.extend_from_slice(&block)
+        }
+
+        ret
+    }
+}
diff --git a/src/writer/gifbuilder.rs b/src/writer/gifbuilder.rs
index 7e5138a..d16be56 100644
--- a/src/writer/gifbuilder.rs
+++ b/src/writer/gifbuilder.rs
@@ -1,73 +1,74 @@
-use crate::block::{Block, ColorTable, ScreenDescriptor, Version, extension::Extension};
+use crate::block::{extension::Extension, Block, ColorTable, ScreenDescriptor, Version};
 use crate::writer::ImageBuilder;
 use crate::Gif;
 
 pub struct GifBuilder {
-	version: Version,
-	width: u16,
-	height: u16,
-	background_color_index: u8,
-	global_color_table: Option<ColorTable>,
-	blocks: Vec<Block>
+    version: Version,
+    width: u16,
+    height: u16,
+    background_color_index: u8,
+    global_color_table: Option<ColorTable>,
+    blocks: Vec<Block>,
 }
 
 impl GifBuilder {
-	pub fn new(version: Version, width: u16, height: u16) -> Self {
-		Self {
-			version,
-			width,
-			height,
-			background_color_index: 0,
-			global_color_table: None,
-			blocks: vec![]
-		}
-	}
+    pub fn new(version: Version, width: u16, height: u16) -> Self {
+        Self {
+            version,
+            width,
+            height,
+            background_color_index: 0,
+            global_color_table: None,
+            blocks: vec![],
+        }
+    }
 
-	pub fn global_color_table(mut self, table: ColorTable) -> Self {
-		self.global_color_table = Some(table);
+    pub fn global_color_table(mut self, table: ColorTable) -> Self {
+        self.global_color_table = Some(table);
 
-		self
-	}
+        self
+    }
 
-	pub fn background_color_index(mut self, ind: u8) -> Self {
-		if self.global_color_table.is_none() {
-			//TODO: Throw error or let it go by, who knows
-			panic!("Setting background color index with noGCT!");
-		}
+    pub fn background_color_index(mut self, ind: u8) -> Self {
+        if self.global_color_table.is_none() {
+            //TODO: Throw error or let it go by, who knows
+            panic!("Setting background color index with noGCT!");
+        }
 
-		self.background_color_index = ind;
-		self
-	}
+        self.background_color_index = ind;
+        self
+    }
 
-	pub fn image(mut self, ib: ImageBuilder) -> Self {
-		self.blocks.push(Block::IndexedImage(ib.build()));
-		self
-	}
+    pub fn image(mut self, ib: ImageBuilder) -> Self {
+        self.blocks.push(Block::IndexedImage(ib.build()));
+        self
+    }
 
-	pub fn extension(mut self, ext: Extension) -> Self {
-		self.blocks.push(Block::Extension(ext));
-		self
-	}
+    pub fn extension(mut self, ext: Extension) -> Self {
+        self.blocks.push(Block::Extension(ext));
+        self
+    }
 
-	pub fn build(self) -> Gif {
-		let mut lsd = ScreenDescriptor {
-			width: self.width,
-			height: self.height,
-			packed: 0, // Set later
-			background_color_index: self.background_color_index,
-			pixel_aspect_ratio: 0 //TODO: Allow configuring
-		};
+    pub fn build(self) -> Gif {
+        let mut lsd = ScreenDescriptor {
+            width: self.width,
+            height: self.height,
+            packed: 0, // Set later
+            background_color_index: self.background_color_index,
+            pixel_aspect_ratio: 0, //TODO: Allow configuring
+        };
 
-		if let Some(gct) = &self.global_color_table {
-			lsd.color_table_present(true);
-			lsd.color_table_size(gct.len() as u8);
-		}
+        if let Some(gct) = &self.global_color_table {
+            println!("build {}", gct.len());
+            lsd.set_color_table_present(true);
+            lsd.set_color_table_size((gct.len() - 1) as u8);
+        }
 
-		Gif {
-			header: self.version,
-			screen_descriptor: lsd,
-			global_color_table: self.global_color_table,
-			blocks: self.blocks
-		}
-	}
-}
\ No newline at end of file
+        Gif {
+            header: self.version,
+            screen_descriptor: lsd,
+            global_color_table: self.global_color_table,
+            blocks: self.blocks,
+        }
+    }
+}
diff --git a/src/writer/imagebuilder.rs b/src/writer/imagebuilder.rs
index f2156ac..d38687e 100644
--- a/src/writer/imagebuilder.rs
+++ b/src/writer/imagebuilder.rs
@@ -1,71 +1,71 @@
-use crate::block::{ColorTable, IndexedImage, ImageDescriptor};
+use crate::block::{ColorTable, ImageDescriptor, IndexedImage};
 
 pub struct ImageBuilder {
-	left_offset: u16,
-	top_offset: u16,
-	width: u16,
-	height: u16,
-	color_table: Option<ColorTable>,
-	indicies: Vec<u8>
+    left_offset: u16,
+    top_offset: u16,
+    width: u16,
+    height: u16,
+    color_table: Option<ColorTable>,
+    indicies: Vec<u8>,
 }
 
 impl ImageBuilder {
-	pub fn new(width: u16, height: u16) -> Self {
-		Self {
-			left_offset: 0,
-			top_offset: 0,
-			width,
-			height,
-			color_table: None,
-			indicies: vec![]
-		}
-	}
+    pub fn new(width: u16, height: u16) -> Self {
+        Self {
+            left_offset: 0,
+            top_offset: 0,
+            width,
+            height,
+            color_table: None,
+            indicies: vec![],
+        }
+    }
 
-	pub fn offsets(mut self, left_offset: u16, top_offset: u16) -> Self {
-		self.left_offset = left_offset;
-		self.top_offset = top_offset;
-		self
-	}
+    pub fn offsets(mut self, left_offset: u16, top_offset: u16) -> Self {
+        self.left_offset = left_offset;
+        self.top_offset = top_offset;
+        self
+    }
 
-	pub fn left_offset(mut self, offset: u16) -> Self {
-		self.left_offset = offset;
-		self
-	}
+    pub fn left_offset(mut self, offset: u16) -> Self {
+        self.left_offset = offset;
+        self
+    }
 
-	pub fn top_offset(mut self, offset: u16) -> Self {
-		self.top_offset = offset;
-		self
-	}
+    pub fn top_offset(mut self, offset: u16) -> Self {
+        self.top_offset = offset;
+        self
+    }
 
-	pub fn color_table(mut self, table: ColorTable) -> Self {
-		self.color_table = Some(table);
+    pub fn color_table(mut self, table: ColorTable) -> Self {
+        self.color_table = Some(table);
 
-		self
-	}
+        self
+    }
 
-	pub fn indicies(mut self, vec: Vec<u8>) -> Self {
-		self.indicies = vec;
-		self
-	}
+    pub fn indicies(mut self, vec: Vec<u8>) -> Self {
+        self.indicies = vec;
+        self
+    }
 
-	pub fn build(self) -> IndexedImage {
-		let mut imgdesc = ImageDescriptor {
-			left: self.left_offset,
-			top: self.top_offset,
-			width: self.width,
-			height: self.height,
-			packed: 0 // Set later
-		};
+    pub fn build(self) -> IndexedImage {
+        let mut imgdesc = ImageDescriptor {
+            left: self.left_offset,
+            top: self.top_offset,
+            width: self.width,
+            height: self.height,
+            packed: 0, // Set later
+        };
 
-		if let Some(lct) = &self.color_table {
-			imgdesc.color_table_present(true);
-			imgdesc.color_table_size(lct.packed_len());
-		}
+        if let Some(lct) = &self.color_table {
+            imgdesc.set_color_table_present(true);
+            imgdesc.set_color_table_size(lct.packed_len());
+        }
 
-		IndexedImage {
-			image_descriptor: imgdesc,
-			local_color_table: self.color_table,
-			indicies: self.indicies
-		}
-	}
+        IndexedImage {
+            image_descriptor: imgdesc,
+            local_color_table: self.color_table,
+            indicies: self.indicies,
+        }
+    }
 }