Create new library Raw-rs including a basic TIFF decoder (#1757)

* add a basic tiff decoder in raw-rs

* cargo fmt

* add readme and license files

* add warning about being in-progress

* add testing framework for raw-rs

* add new type IFD and rename tag

* remove test_each and merge into single test

* cargo fmt

* make sure images folder stays in git

* rename image_length with image_height

* change name of test file

* Readme changes

---------

Co-authored-by: Keavon Chambers <keavon@keavon.com>

libraries/raw-rs/src/lib.rs

@@ -0,0 +1,49 @@
+pub mod decoder;
+pub mod tiff;
+
+use std::io::{Read, Seek};
+use thiserror::Error;
+use tiff::file::TiffRead;
+use tiff::tags::{COMPRESSION, SUBIFD};
+use tiff::{Ifd, TiffError};
+
+pub struct RawImage {
+	pub data: Vec<u16>,
+	pub width: usize,
+	pub height: usize,
+}
+
+pub struct Image<T> {
+	pub data: Vec<T>,
+	pub width: usize,
+	pub height: usize,
+	pub channels: u8,
+}
+
+pub fn decode<R: Read + Seek>(reader: &mut R) -> Result<RawImage, DecoderError> {
+	let mut file = TiffRead::new(reader)?;
+	let ifd = Ifd::new_first_ifd(&mut file)?;
+
+	// TODO: This is only for the tests to pass for now. Replace this with the correct implementation when the decoder is complete.
+	let subifd = ifd.get(SUBIFD, &mut file)?;
+
+	Ok(decoder::uncompressed::decode(subifd, &mut file))
+}
+
+pub fn process_8bit(image: RawImage) -> Image<u8> {
+	todo!()
+}
+
+pub fn process_16bit(image: RawImage) -> Image<u16> {
+	todo!()
+}
+
+#[derive(Error, Debug)]
+pub enum DecoderError {
+	#[error("An error occurred when trying to parse the TIFF format")]
+	TiffError(#[from] TiffError),
+	#[error("An error occurred when converting integer from one type to another")]
+	ConversionError(#[from] std::num::TryFromIntError),
+	#[error("An IO Error ocurred")]
+	IoError(#[from] std::io::Error),
+}