9 files changed, 386 insertions, 246 deletions

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"),
+        }
+    }
+}