commit ec190070ee9fbfeaa919c297cc294c1f55599f20
Author: G2-Games <ke0bhogsg@gmail.com>
Date:   Sun Jul 21 23:28:59 2024 -0500

    Initial commit, encoding

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..66cbc0c
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,7 @@
+/target
+
+# Ignore images
+*.png
+*.dpf
+*.raw
+*.rgba
diff --git a/Cargo.lock b/Cargo.lock
new file mode 100644
index 0000000..a9b43e4
--- /dev/null
+++ b/Cargo.lock
@@ -0,0 +1,16 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "byteorder"
+version = "1.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1fd0f2584146f6f2ef48085050886acf353beff7305ebd1ae69500e27c67f64b"
+
+[[package]]
+name = "dangoware_format"
+version = "0.1.0"
+dependencies = [
+ "byteorder",
+]
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..34711a9
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,7 @@
+[package]
+name = "dangoware_format"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+byteorder = "1.5.0"
diff --git a/src/binio.rs b/src/binio.rs
new file mode 100644
index 0000000..334d0e4
--- /dev/null
+++ b/src/binio.rs
@@ -0,0 +1,116 @@
+pub struct BitIo {
+    data: Vec<u8>,
+    byte_offset: usize,
+    bit_offset: usize,
+
+    byte_size: usize,
+}
+
+impl BitIo {
+    /// Create a new BitIO reader and writer over some data
+    pub fn new(data: Vec<u8>) -> Self {
+        Self {
+            data,
+            byte_offset: 0,
+            bit_offset: 0,
+            byte_size: 0,
+        }
+    }
+
+    /// Get the byte offset of the reader
+    pub fn byte_offset(&self) -> usize {
+        self.byte_offset
+    }
+
+    /// Get the byte size of the reader
+    pub fn byte_size(&self) -> usize {
+        self.byte_size
+    }
+
+    /// Get the current bytes up to `byte_size` in the reader
+    pub fn bytes(&self) -> Vec<u8> {
+        self.data[..self.byte_size].to_vec()
+    }
+
+    /// Read some bits from the buffer
+    pub fn read_bit(&mut self, bit_len: usize) -> u64 {
+        if bit_len > 8 * 8 {
+            panic!("Cannot read more than 64 bits")
+        }
+
+        if bit_len % 8 == 0 && self.bit_offset == 0 {
+            return self.read(bit_len / 8);
+        }
+
+        let mut result = 0;
+        for i in 0..bit_len {
+            let bit_value = ((self.data[self.byte_offset] as usize >> self.bit_offset) & 1) as u64;
+            self.bit_offset += 1;
+
+            if self.bit_offset == 8 {
+                self.byte_offset += 1;
+                self.bit_offset = 0;
+            }
+
+            result |= bit_value << i;
+        }
+
+        result
+    }
+
+    /// Read some bytes from the buffer
+    pub fn read(&mut self, byte_len: usize) -> u64 {
+        if byte_len > 8 {
+            panic!("Cannot read more than 8 bytes")
+        }
+
+        let mut padded_slice = [0u8; 8];
+        padded_slice.copy_from_slice(&self.data[self.byte_offset..self.byte_offset + byte_len]);
+        self.byte_offset += byte_len;
+
+        u64::from_le_bytes(padded_slice)
+    }
+
+    /// Write some bits to the buffer
+    pub fn write_bit(&mut self, data: u64, bit_len: usize) {
+        if bit_len > 8 * 8 {
+            panic!("Cannot write more than 64 bits");
+        }
+
+        if bit_len % 8 == 0 && self.bit_offset == 0 {
+            self.write(data, bit_len / 8);
+            return;
+        }
+
+        for i in 0..bit_len {
+            let bit_value = (data >> i) & 1;
+
+            self.data[self.byte_offset] &= !(1 << self.bit_offset);
+
+            self.data[self.byte_offset] |= (bit_value << self.bit_offset) as u8;
+
+            self.bit_offset += 1;
+            if self.bit_offset == 8 {
+                self.byte_offset += 1;
+                self.bit_offset = 0;
+            }
+        }
+
+        self.byte_size = self.byte_offset + (self.bit_offset + 7) / 8;
+    }
+
+    pub fn write(&mut self, data: u64, byte_len: usize) {
+        if byte_len > 8 {
+            panic!("Cannot write more than 8 bytes")
+        }
+
+        let mut padded_slice = [0u8; 8];
+        padded_slice.copy_from_slice(&data.to_le_bytes());
+
+        self.data[self.byte_offset..self.byte_offset + byte_len]
+            .copy_from_slice(&padded_slice[..byte_len]);
+        self.byte_offset += byte_len;
+
+        self.byte_size = self.byte_offset + (self.bit_offset + 7) / 8;
+    }
+}
diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 0000000..98fa887
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,281 @@
+mod binio;
+
+use std::{collections::HashMap, fs::{read, File}, io::Write};
+
+use binio::BitIo;
+use byteorder::{WriteBytesExt, LE};
+
+fn main() {
+    let image_data = read("littlespace.rgba").unwrap();
+    let mut file = File::create("test.di").unwrap();
+    let mut raw_diffed = File::create("test.raw").unwrap();
+
+    let header = Header {
+        magic: *b"dangoimg",
+        width: 64,
+        height: 64,
+    };
+
+    // Write out the header
+    file.write_all(&header.to_bytes()).unwrap();
+
+    let modified_data = diff_line(header.width, header.height, &image_data);
+
+    raw_diffed.write_all(&modified_data).unwrap();
+
+    // Compress the image data
+    let (compressed_data, compression_info) = compress2(&modified_data);
+
+    // Write out compression info
+    compression_info.write_into(&mut file).unwrap();
+
+    // Write out compressed data
+    file.write_all(&compressed_data).unwrap();
+}
+
+struct Header {
+    magic: [u8; 8],
+
+    width: u32,
+    height: u32,
+}
+
+impl Header {
+    fn to_bytes(&self) -> [u8; 16] {
+        let mut buf = [0u8; 16];
+
+        buf[0..8].copy_from_slice(&self.magic);
+        buf[8..12].copy_from_slice(&self.width.to_le_bytes());
+        buf[12..16].copy_from_slice(&self.height.to_le_bytes());
+
+        buf
+    }
+}
+
+/*
+fn diff_line(width: u32, height: u32, input: &[u8]) -> Vec<u8> {
+    let mut data = Vec::with_capacity(input.len());
+
+    let block_height = f32::ceil(height as f32 / 3.0) as usize;
+    let pixel_byte_count = 32 >> 3;
+    let line_byte_count = (width * pixel_byte_count as u32) as usize;
+
+    let mut curr_line;
+    let mut prev_line: Vec<u8> = Vec::with_capacity(line_byte_count);
+
+    let mut i = 0;
+    for y in 0..height {
+        curr_line = input[i..i + line_byte_count].to_vec();
+        if y % block_height as u32 != 0 {
+            curr_line.iter_mut().zip(prev_line.iter_mut()).for_each(|(c, p)| {
+                *c = c.wrapping_sub(*p);
+                *p = p.wrapping_add(*c);
+            });
+        } else {
+            prev_line.clone_from(&curr_line);
+        }
+
+        data.extend_from_slice(&curr_line);
+        i += line_byte_count;
+    }
+
+    data
+}
+*/
+
+
+fn diff_line(width: u32, height: u32, input: &[u8]) -> Vec<u8> {
+    let mut data = Vec::with_capacity(width as usize * 3);
+    let mut alpha_data = Vec::with_capacity(width as usize);
+
+    let block_height = (f32::ceil(height as f32 / 3.0) as u16) as usize;
+    let pixel_byte_count = 4;
+    let line_byte_count = (width * pixel_byte_count as u32) as usize;
+
+    let mut curr_line: Vec<u8>;
+    let mut prev_line: Vec<u8> = Vec::with_capacity(width as usize * 3);
+
+    let mut curr_alpha: Vec<u8>;
+    let mut prev_alpha: Vec<u8> = Vec::with_capacity(width as usize);
+
+    let mut i = 0;
+    for y in 0..height {
+        curr_line = input[i..i + line_byte_count]
+            .windows(4)
+            .step_by(4)
+            .flat_map(|r| &r[0..3])
+            .copied()
+            .collect();
+        curr_alpha = input[i..i + line_byte_count]
+            .iter()
+            .skip(3)
+            .step_by(4)
+            .copied()
+            .collect();
+
+        if y % block_height as u32 != 0 {
+            for x in 0..width as usize * 3 {
+                curr_line[x] = curr_line[x].wrapping_sub(prev_line[x]);
+                prev_line[x] = prev_line[x].wrapping_add(curr_line[x]);
+            }
+            for x in 0..width as usize {
+                curr_alpha[x] = curr_alpha[x].wrapping_sub(prev_alpha[x]);
+                prev_alpha[x] = prev_alpha[x].wrapping_add(curr_alpha[x]);
+            }
+        } else {
+            prev_line.clone_from(&curr_line);
+            prev_alpha.clone_from(&curr_alpha);
+        }
+
+        data.extend_from_slice(&curr_line);
+        alpha_data.extend_from_slice(&curr_alpha);
+        i += line_byte_count;
+    }
+
+    data.extend_from_slice(&alpha_data);
+
+    data
+}
+
+
+/// The size of compressed data in each chunk
+#[derive(Debug, Clone, Copy)]
+pub struct ChunkInfo {
+    /// The size of the data when compressed
+    pub size_compressed: usize,
+
+    /// The size of the original uncompressed data
+    pub size_raw: usize,
+}
+
+/// A CZ# file's information about compression chunks
+#[derive(Default, Debug, Clone)]
+pub struct CompressionInfo {
+    /// Number of compression chunks
+    pub chunk_count: usize,
+
+    /// Total size of the data when compressed
+    pub total_size_compressed: usize,
+
+    /// The compression chunk information
+    pub chunks: Vec<ChunkInfo>,
+
+    /// Length of the compression chunk info
+    pub length: usize,
+}
+
+impl CompressionInfo {
+    pub fn write_into<T: WriteBytesExt + Write>(
+        &self,
+        output: &mut T,
+    ) -> Result<(), std::io::Error> {
+        output.write_u32::<LE>(self.chunk_count as u32)?;
+
+        for chunk in &self.chunks {
+            output.write_u32::<LE>(chunk.size_compressed as u32)?;
+            output.write_u32::<LE>(chunk.size_raw as u32)?;
+        }
+
+        Ok(())
+    }
+}
+
+pub fn compress2(data: &[u8]) -> (Vec<u8>, CompressionInfo) {
+    let mut part_data;
+
+    let mut offset = 0;
+    let mut count;
+    let mut last: Vec<u8> = Vec::new();
+
+    let mut output_buf: Vec<u8> = Vec::new();
+    let mut output_info = CompressionInfo {
+        ..Default::default()
+    };
+
+    loop {
+        (count, part_data, last) = compress_lzw2(&data[offset..], last);
+        if count == 0 {
+            break;
+        }
+        offset += count;
+
+        output_buf.write_all(&part_data).unwrap();
+
+        output_info.chunks.push(ChunkInfo {
+            size_compressed: part_data.len(),
+            size_raw: count,
+        });
+
+        output_info.chunk_count += 1;
+    }
+
+    if output_info.chunk_count == 0 {
+        panic!("No chunks compressed!")
+    }
+
+    output_info.total_size_compressed = output_buf.len();
+    (output_buf, output_info)
+}
+
+fn compress_lzw2(data: &[u8], last: Vec<u8>) -> (usize, Vec<u8>, Vec<u8>) {
+    let mut count = 0;
+    let mut dictionary = HashMap::new();
+    for i in 0..=255 {
+        dictionary.insert(vec![i], i as u64);
+    }
+    let mut dictionary_count = (dictionary.len() + 1) as u64;
+
+    let mut element = Vec::new();
+    if last.is_empty() {
+        element = last
+    }
+
+    let mut bit_io = BitIo::new(vec![0u8; 0xF0000]);
+    let write_bit = |bit_io: &mut BitIo, code: u64| {
+        if code > 0x7FFF {
+            bit_io.write_bit(1, 1);
+            bit_io.write_bit(code, 18);
+        } else {
+            bit_io.write_bit(0, 1);
+            bit_io.write_bit(code, 15);
+        }
+    };
+
+    for c in data.iter() {
+        let mut entry = element.clone();
+        entry.push(*c);
+
+        if dictionary.contains_key(&entry) {
+            element = entry
+        } else {
+            write_bit(&mut bit_io, *dictionary.get(&element).unwrap());
+            dictionary.insert(entry, dictionary_count);
+            element = vec![*c];
+            dictionary_count += 1;
+        }
+
+        count += 1;
+
+        if dictionary_count >= 0x3FFFE {
+            count -= 1;
+            break
+        }
+    }
+
+    let last_element = element;
+    if bit_io.byte_size() == 0 {
+        if !last_element.is_empty() {
+            for c in last_element {
+                write_bit(&mut bit_io, *dictionary.get(&vec![c]).unwrap());
+            }
+        }
+        return (count, bit_io.bytes(), Vec::new());
+    } else if bit_io.byte_size() < 0x87BDF {
+        if !last_element.is_empty() {
+            write_bit(&mut bit_io, *dictionary.get(&last_element).unwrap());
+        }
+        return (count, bit_io.bytes(), Vec::new());
+    }
+
+    (count, bit_io.bytes(), last_element)
+}