commit 16d1838e5bca2e90ca7cf8584a786b84fc409708
Author: Silas Bartha <silas@exvacuum.dev>
Date: Mon May 27 11:18:36 2024 -0400
Initial Commit
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..ea8c4bf
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+/target
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..9a471d6
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,16 @@
+[package]
+name = "occule"
+version = "0.1.0"
+edition = "2021"
+
+[features]
+default = ["jpg", "png", "lossless"]
+jpg = []
+png = []
+lossless = []
+
+[dependencies]
+colored = "2.1.0"
+image = "0.24"
+img-parts = "0.3.0"
+thiserror = "1.0.61"
diff --git a/src/codec.rs b/src/codec.rs
new file mode 100644
index 0000000..03cdf15
--- /dev/null
+++ b/src/codec.rs
@@ -0,0 +1,14 @@
+pub trait Codec {
+ type Carrier;
+ type Payload;
+ type Output;
+ type Error;
+
+ fn encode(
+ &self,
+ carrier: impl Into<Self::Carrier>,
+ payload: impl Into<Self::Payload>,
+ ) -> Result<Self::Output, Self::Error>;
+
+ fn decode(&self, encoded: impl Into<Self::Output>) -> Result<(Self::Carrier, Self::Payload), Self::Error>;
+}
diff --git a/src/jpg/mod.rs b/src/jpg/mod.rs
new file mode 100644
index 0000000..3d6bdc3
--- /dev/null
+++ b/src/jpg/mod.rs
@@ -0,0 +1,2 @@
+mod segment;
+pub use segment::*;
diff --git a/src/jpg/segment.rs b/src/jpg/segment.rs
new file mode 100644
index 0000000..f54d0e2
--- /dev/null
+++ b/src/jpg/segment.rs
@@ -0,0 +1,66 @@
+use std::{mem::size_of, usize};
+
+use img_parts::jpeg::{markers, Jpeg, JpegSegment};
+use thiserror::Error;
+
+use crate::codec::Codec;
+
+#[derive(Debug, PartialEq, Eq)]
+pub struct JpegSegmentCodec {
+ pub start_index: usize,
+}
+
+impl Codec for JpegSegmentCodec {
+ type Carrier = Vec<u8>;
+ type Payload = Vec<u8>;
+ type Output = Self::Carrier;
+ type Error = JpegSegmentError;
+
+ fn encode(&self, carrier: impl Into<Self::Carrier>, payload: impl Into<Self::Payload>) -> Result<Self::Output, Self::Error> {
+ let mut jpeg = match Jpeg::from_bytes(carrier.into().into()) {
+ Ok(image) => image,
+ Err(err) => return Err(JpegSegmentError::ParseFailed { inner: err })
+ };
+ let mut payload_bytes: Self::Carrier = payload.into();
+ let segment_count = ((payload_bytes.len() + size_of::<u64>()) as u64).div_ceil((u16::MAX as usize - size_of::<u16>()) as u64);
+ payload_bytes.splice(0..0, segment_count.to_le_bytes());
+ for (index, payload_chunk) in payload_bytes.chunks(u16::MAX as usize - size_of::<u16>()).enumerate() {
+ let segment = JpegSegment::new_with_contents(markers::COM, payload_chunk.to_vec().into());
+ jpeg.segments_mut().insert(self.start_index + index, segment);
+ }
+ Ok(jpeg.encoder().bytes().to_vec())
+ }
+
+ fn decode(&self, encoded: impl Into<Self::Output>) -> Result<(Self::Carrier, Self::Payload), Self::Error> {
+ let mut jpeg = match Jpeg::from_bytes(encoded.into().into()) {
+ Ok(image) => image,
+ Err(err) => return Err(JpegSegmentError::ParseFailed { inner: err })
+ };
+ let segment = jpeg.segments_mut().remove(self.start_index);
+ let segment_bytes = segment.contents();
+ let segment_count = u64::from_le_bytes(segment_bytes[0..size_of::<u64>()].try_into().unwrap()) as usize;
+ let mut payload_vec: Vec<u8> = Vec::with_capacity((u16::MAX as usize - size_of::<u16>()) * segment_count);
+ payload_vec.extend(segment_bytes[size_of::<u64>()..].to_vec());
+
+ for _ in 0..segment_count-1 {
+ let segment = jpeg.segments_mut().remove(self.start_index);
+ payload_vec.extend(segment.contents());
+ }
+
+ Ok((jpeg.encoder().bytes().to_vec(), payload_vec))
+ }
+}
+
+impl Default for JpegSegmentCodec {
+ fn default() -> Self {
+ Self {
+ start_index: 3,
+ }
+ }
+}
+
+#[derive(Error, Debug)]
+pub enum JpegSegmentError {
+ #[error("Failed to parse JPEG data: {inner:?}")]
+ ParseFailed { inner: img_parts::Error }
+}
diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..a1ed909
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,7 @@
+pub mod codec;
+
+#[cfg(feature = "jpg")]
+pub mod jpg;
+
+#[cfg(feature = "lossless")]
+pub mod lossless;
diff --git a/src/lossless/champleve.rs b/src/lossless/champleve.rs
new file mode 100644
index 0000000..948408c
--- /dev/null
+++ b/src/lossless/champleve.rs
@@ -0,0 +1,139 @@
+use std::cmp::Ordering;
+
+use image::{ColorType, DynamicImage, GenericImageView, Pixel};
+use thiserror::Error;
+
+use crate::codec::Codec;
+
+#[derive(Debug)]
+pub struct ChampleveCodec;
+
+impl Codec for ChampleveCodec {
+ type Carrier = DynamicImage;
+ type Payload = Vec<u8>;
+ type Output = Self::Carrier;
+ type Error = ChampleveError;
+
+ fn encode(&self, carrier: impl Into<Self::Carrier>, payload: impl Into<Self::Payload>) -> Result<Self::Output, Self::Error> {
+ let mut image: DynamicImage = carrier.into();
+ let payload: Vec<u8> = payload.into();
+
+ if image.pixels().count() < payload.len() {
+ return Err(ChampleveError::PayloadTooBig);
+ }
+
+ let mut payload_iter = payload.iter();
+
+ match image {
+ DynamicImage::ImageRgba8(ref mut image) => {
+ for pixel in image.pixels_mut() {
+ if let Some(payload_byte) = payload_iter.next() {
+ encode_pixel(pixel, *payload_byte, false);
+ } else {
+ encode_pixel(pixel, 0, true);
+ }
+ }
+ },
+ DynamicImage::ImageRgb8(ref mut image) => {
+ for pixel in image.pixels_mut() {
+ if let Some(payload_byte) = payload_iter.next() {
+ encode_pixel(pixel, *payload_byte, false);
+ } else {
+ encode_pixel(pixel, 0, true);
+ }
+ }
+ },
+ _ => return Err(ChampleveError::UnsupportedFormat { format: image.color() })
+ }
+
+ Ok(image)
+ }
+
+ fn decode(&self, carrier: impl Into<Self::Output>) -> Result<(Self::Carrier, Self::Payload), ChampleveError> {
+ let mut image: DynamicImage = carrier.into();
+ let mut payload: Vec<u8> = Vec::new();
+
+ match image {
+ DynamicImage::ImageRgba8(ref mut image) => {
+ for pixel in image.pixels_mut() {
+ if let Some(payload_byte) = decode_pixel(pixel) {
+ payload.push(payload_byte);
+ } else {
+ break;
+ }
+ }
+ },
+ DynamicImage::ImageRgb8(ref mut image) => {
+ for pixel in image.pixels_mut() {
+ if let Some(payload_byte) = decode_pixel(pixel) {
+ payload.push(payload_byte);
+ } else {
+ break;
+ }
+ }
+ },
+ _ => return Err(ChampleveError::UnsupportedFormat { format: image.color() })
+ }
+
+ Ok((image, payload))
+ }
+}
+
+fn encode_pixel<P: Pixel<Subpixel = u8>>(pixel: &mut P, payload_byte: u8, end_of_data: bool) {
+ let mut bits_remaining: i32 = 8;
+ for channel in pixel.channels_mut() {
+ *channel &= 0b11111000;
+ bits_remaining -= 3;
+ if bits_remaining <= -3 {
+ break;
+ }
+
+ let mask = match bits_remaining.cmp(&0) {
+ Ordering::Less => payload_byte << -bits_remaining,
+ _ => payload_byte >> bits_remaining,
+ } & 0b00000111;
+
+ *channel |= mask;
+ }
+
+ // Add end-of-data marker to final bit if necessary
+ if end_of_data {
+ *pixel.channels_mut().last_mut().unwrap() |= 1;
+ }
+}
+
+fn decode_pixel<P: Pixel<Subpixel = u8>>(pixel: &mut P) -> Option<u8> {
+
+ // Final bit as end-of-data marker
+ if pixel.channels().last().unwrap() & 1 == 1 {
+ return None;
+ }
+
+ let mut bits_remaining: i32 = 8;
+ let mut payload_byte: u8 = 0;
+ for channel in pixel.channels_mut() {
+ bits_remaining -= 3;
+ if bits_remaining <= -3 {
+ break;
+ }
+
+ let channel_bits = *channel & 0b00000111;
+ *channel &= 0b11111000;
+ let mask = match bits_remaining.cmp(&0) {
+ Ordering::Less => channel_bits >> -bits_remaining,
+ _ => channel_bits << bits_remaining,
+ };
+ payload_byte |= mask;
+ }
+ Some(payload_byte)
+}
+
+#[derive(Error, Debug)]
+pub enum ChampleveError {
+ #[error("Payload is too big for the carrier. Choose a smaller payload or an image with greater pixel dimensions.")]
+ PayloadTooBig,
+ #[error("Specified image format ({format:?}) is unsupported.")]
+ UnsupportedFormat {
+ format: ColorType
+ },
+}
diff --git a/src/lossless/mod.rs b/src/lossless/mod.rs
new file mode 100644
index 0000000..a9ae225
--- /dev/null
+++ b/src/lossless/mod.rs
@@ -0,0 +1,2 @@
+mod champleve;
+pub use champleve::*;