From 9da8d686830242467e7b60de5666f5ecbe248f8b Mon Sep 17 00:00:00 2001
From: G2-Games <ke0bhogsg@gmail.com>
Date: Thu, 9 May 2024 21:19:00 -0500
Subject: [PATCH] Added CZ3 encoding

---
 cz/src/compression.rs | 32 ++++++++++++++++++++++++++++++++
 cz/src/dynamic.rs     |  5 +----
 cz/src/formats/cz3.rs | 31 ++++++++++++++++++++++++-------
 3 files changed, 57 insertions(+), 11 deletions(-)

diff --git a/cz/src/compression.rs b/cz/src/compression.rs
index 2d271d9..b1ae0ed 100644
--- a/cz/src/compression.rs
+++ b/cz/src/compression.rs
@@ -289,6 +289,38 @@ pub fn line_diff<T: CzHeader>(header: &T, data: &[u8]) -> Vec<u8> {
     output_buf
 }
 
+pub fn diff_line<T: CzHeader>(header: &T, input: &[u8]) -> Vec<u8> {
+    let width = header.width() as u32;
+    let height = header.height() as u32;
+
+    let mut data = Vec::with_capacity(input.len());
+
+    let block_height =
+        (f32::ceil(height as f32 / 3.0) as u16) as usize;
+    let pixel_byte_count = header.depth() >> 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 {
+            for x in 0..line_byte_count {
+                curr_line[x] -= prev_line[x];
+                prev_line[x] += curr_line[x];
+            }
+        } else {
+            prev_line.clone_from(&curr_line);
+        }
+
+        data.extend_from_slice(&curr_line);
+        i += line_byte_count;
+    }
+
+    data
+}
 
 pub fn compress(
     data: &[u8],
diff --git a/cz/src/dynamic.rs b/cz/src/dynamic.rs
index e7b7dce..eec5caa 100644
--- a/cz/src/dynamic.rs
+++ b/cz/src/dynamic.rs
@@ -63,9 +63,6 @@ impl DynamicCz {
             CzVersion::CZ5 => unimplemented!(),
         };
 
-        let mut file = File::create("raw1").unwrap();
-        file.write_all(&bitmap).unwrap();
-
         let image_size = header_common.width() as usize * header_common.height() as usize;
         if bitmap.len() != image_size * (header_common.depth() >> 3) as usize {
             // If the bitmap is smaller or larger than the image size, it is likely wrong
@@ -109,7 +106,7 @@ impl DynamicCz {
             CzVersion::CZ0 => cz0::encode(&mut out_file, &output_bitmap)?,
             CzVersion::CZ1 => cz1::encode(&mut out_file, &output_bitmap)?,
             CzVersion::CZ2 => todo!(),
-            CzVersion::CZ3 => todo!(),
+            CzVersion::CZ3 => cz3::encode(&mut out_file, &output_bitmap, &self.header_common)?,
             CzVersion::CZ4 => todo!(),
             CzVersion::CZ5 => todo!(),
         }
diff --git a/cz/src/formats/cz3.rs b/cz/src/formats/cz3.rs
index 5cf6f72..dea8f0f 100644
--- a/cz/src/formats/cz3.rs
+++ b/cz/src/formats/cz3.rs
@@ -1,12 +1,13 @@
-use std::io::{Read, Seek, SeekFrom};
-use byteorder::ReadBytesExt;
+use std::io::{Read, Write, Seek, SeekFrom};
+use byteorder::{ReadBytesExt, WriteBytesExt};
 
-use crate::common::{CommonHeader, CzError};
-use crate::compression::{decompress, line_diff, get_chunk_info};
+use crate::common::{CommonHeader, CzError, CzHeader};
+use crate::compression::{compress, decompress, diff_line, get_chunk_info, line_diff};
 
-pub fn decode<T: Seek + ReadBytesExt + Read>(bytes: &mut T, header: &CommonHeader)
-    -> Result<Vec<u8>, CzError>
-{
+pub fn decode<T: Seek + ReadBytesExt + Read>(
+    bytes: &mut T,
+    header: &CommonHeader
+) -> Result<Vec<u8>, CzError> {
     let block_info = get_chunk_info(bytes)?;
     bytes.seek(SeekFrom::Start(block_info.length as u64))?;
 
@@ -15,3 +16,19 @@ pub fn decode<T: Seek + ReadBytesExt + Read>(bytes: &mut T, header: &CommonHeade
 
     Ok(bitmap)
 }
+
+pub fn encode<T: WriteBytesExt + Write, H: CzHeader>(
+    output: &mut T,
+    bitmap: &[u8],
+    header: &H,
+) -> Result<(), CzError> {
+    let bitmap = diff_line(header, bitmap);
+
+    let (compressed_data, compressed_info) = compress(&bitmap, 65277);
+
+    compressed_info.write_into(output)?;
+
+    output.write_all(&compressed_data)?;
+
+    Ok(())
+}