Increased speed of CZ3 and 4 decoding, feature gate for image

cz/Cargo.toml

@@ -6,8 +6,11 @@ description="""
 A encoder/decoder for CZ# image files used in the LUCA System Engine.
 """
 
+[features]
+png = ["dep:image"]
+
 [dependencies]
 byteorder = "1.5.0"
 thiserror = "1.0.59"
-image = { version = "0.25.1", default-features = false, features = ["png"] }
 imagequant = "4.3.1"
+image = { version = "0.25", default-features = false, features = ["png"], optional = true }

cz/src/binio.rs

@@ -1,4 +1,9 @@
-pub struct BitIO {
+pub enum BitError {
+    InputLength
+}
+
+
+pub struct BitIo {
     data: Vec<u8>,
     byte_offset: usize,
     bit_offset: usize,
@@ -6,7 +11,8 @@ pub struct BitIO {
     byte_size: usize,
 }
 
-impl BitIO {
+impl BitIo {
+    /// Create a new BitIO reader and writer over some data
     pub fn new(data: Vec<u8>) -> Self {
         Self {
             data,
@@ -16,20 +22,23 @@ impl BitIO {
         }
     }
 
+    /// 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 {
-        //print!("{}: ", bit_len);
         if bit_len > 8 * 8 {
             panic!()
         }
@@ -54,6 +63,7 @@ impl BitIO {
         result
     }
 
+    /// Read some bytes from the buffer
     pub fn read(&mut self, byte_len: usize) -> u64 {
         if byte_len > 8 {
             panic!()
@@ -66,6 +76,7 @@ impl BitIO {
         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!();
@@ -93,9 +104,9 @@ impl BitIO {
         self.byte_size = self.byte_offset + (self.bit_offset + 7) / 8;
     }
 
-    pub fn write(&mut self, data: u64, byte_len: usize) {
+    pub fn write(&mut self, data: u64, byte_len: usize) -> Result<(), BitError> {
         if byte_len > 8 {
-            panic!()
+            return Err(BitError::InputLength);
         }
 
         let mut padded_slice = [0u8; 8];
@@ -106,5 +117,7 @@ impl BitIO {
         self.byte_offset += byte_len;
 
         self.byte_size = self.byte_offset + (self.bit_offset + 7) / 8;
+
+        Ok(())
     }
 }

cz/src/compression.rs

@@ -4,7 +4,7 @@ use std::{
     io::{Read, Seek, Write},
 };
 
-use crate::binio::BitIO;
+use crate::binio::BitIo;
 use crate::common::CzError;
 
 /// The size of compressed data in each chunk
@@ -189,7 +189,7 @@ fn decompress_lzw2(input_data: &[u8], size: usize) -> Vec<u8> {
 
     let data_size = input_data.len();
     data.extend_from_slice(&[0, 0]);
-    let mut bit_io = BitIO::new(data);
+    let mut bit_io = BitIo::new(data);
     let mut w = dictionary.get(&0).unwrap().clone();
 
     let mut element;
@@ -391,8 +391,8 @@ fn compress_lzw2(data: &[u8], size: usize, last: Vec<u8>) -> (usize, Vec<u8>, Ve
         element = last
     }
 
-    let mut bit_io = BitIO::new(vec![0u8; size + 2]);
+    let mut bit_io = BitIo::new(vec![0u8; size + 2]);
-    let write_bit = |bit_io: &mut BitIO, code: u64| {
+    let write_bit = |bit_io: &mut BitIo, code: u64| {
         if code > 0x7FFF {
             bit_io.write_bit(1, 1);
             bit_io.write_bit(code, 18);

cz/src/dynamic.rs

@@ -195,6 +195,7 @@ impl DynamicCz {
     /// Internally, the [`DynamicCz`] struct operates on 32-bit RGBA values,
     /// which is the highest encountered in CZ# files, therefore saving them
     /// as a PNG of the same or better quality is lossless.
+    #[cfg(feature = "png")]
     pub fn save_as_png<P: ?Sized + AsRef<Path>>(
         &self,
         path: &P,

cz/src/formats/cz3.rs

@@ -1,5 +1,6 @@
 use byteorder::{ReadBytesExt, WriteBytesExt};
 use std::io::{Read, Seek, SeekFrom, Write};
+use std::time::Instant;
 
 use crate::common::{CommonHeader, CzError};
 use crate::compression::{compress, decompress, get_chunk_info};
@@ -11,8 +12,13 @@ pub fn decode<T: Seek + ReadBytesExt + Read>(
     let block_info = get_chunk_info(bytes)?;
     bytes.seek(SeekFrom::Start(block_info.length as u64))?;
 
+    let timer = Instant::now();
     let bitmap = decompress(bytes, &block_info)?;
+    dbg!(timer.elapsed());
+
+    let timer = Instant::now();
     let bitmap = line_diff(header, &bitmap);
+    dbg!(timer.elapsed());
 
     Ok(bitmap)
 }
@@ -46,17 +52,17 @@ fn line_diff(header: &CommonHeader, data: &[u8]) -> Vec<u8> {
     let pixel_byte_count = header.depth() >> 3;
     let line_byte_count = (width * pixel_byte_count as u32) as usize;
 
-    let mut curr_line: Vec<u8>;
+    let mut curr_line;
-    let mut prev_line: Vec<u8> = Vec::with_capacity(line_byte_count);
+    let mut prev_line = Vec::with_capacity(line_byte_count);
 
     let mut i = 0;
     for y in 0..height {
         curr_line = data[i..i + line_byte_count].to_vec();
 
         if y % block_height as u32 != 0 {
-            for x in 0..line_byte_count {
+            curr_line.iter_mut().zip(&prev_line).for_each(|(curr_p, prev_p)| {
-                curr_line[x] = u8::wrapping_add(curr_line[x], prev_line[x])
+                *curr_p = curr_p.wrapping_add(*prev_p)
-            }
+            });
         }
 
         prev_line.clone_from(&curr_line);

cz/src/formats/cz4.rs

@@ -1,6 +1,6 @@
 use byteorder::{ReadBytesExt, WriteBytesExt};
-use image::RgbaImage;
 use std::io::{Read, Seek, SeekFrom, Write};
+use std::time::Instant;
 
 use crate::common::{CommonHeader, CzError};
 use crate::compression::{compress, decompress, get_chunk_info};
@@ -12,14 +12,15 @@ pub fn decode<T: Seek + ReadBytesExt + Read>(
     let block_info = get_chunk_info(bytes)?;
     bytes.seek(SeekFrom::Start(block_info.length as u64))?;
 
+    let timer = Instant::now();
     let data = decompress(bytes, &block_info)?;
+    dbg!(timer.elapsed());
 
+    let timer = Instant::now();
+    let output = line_diff(header, &data);
+    dbg!(timer.elapsed());
 
-    let mut picture = image::RgbaImage::new(header.width() as u32, header.height() as u32);
+    Ok(output)
-
-    line_diff(&mut picture, &data);
-
-    Ok(picture.into_raw())
 }
 
 pub fn encode<T: WriteBytesExt + Write>(
@@ -38,9 +39,12 @@ pub fn encode<T: WriteBytesExt + Write>(
     Ok(())
 }
 
-fn line_diff(picture: &mut RgbaImage, data: &[u8]) {
+fn line_diff(header: &CommonHeader, data: &[u8]) -> Vec<u8> {
-    let width = picture.width();
+    let width = header.width() as u32;
-    let height = picture.height();
+    let height = header.height() as u32;
+
+    let mut output_buf = Vec::with_capacity((width * height * 4) as usize);
+
     let block_height = (f32::ceil(height as f32 / 3.0) as u16) as u32;
 
     let mut curr_line;
@@ -49,37 +53,38 @@ fn line_diff(picture: &mut RgbaImage, data: &[u8]) {
     let mut curr_alpha;
     let mut prev_alpha = Vec::with_capacity(width as usize);
 
-    let pcount = (width * height * 3) as usize;
+    let mut rgb_index = 0;
-
+    let mut alpha_index = (width * height * 3) as usize;
-    let mut i = 0;
-    let mut z = 0;
     for y in 0..height {
-        curr_line = data[i..i + width as usize * 3].to_vec();
+        curr_line = data[rgb_index..rgb_index + width as usize * 3].to_vec();
-        curr_alpha = data[pcount + z..pcount + z + width as usize].to_vec();
+        curr_alpha = data[alpha_index..alpha_index + width as usize].to_vec();
 
         if y % block_height != 0 {
-            for x in 0..(width as usize * 3) {
+            curr_line.iter_mut().zip(&prev_line).for_each(|(curr_p, prev_p)| {
-                curr_line[x] = curr_line[x].wrapping_add(prev_line[x])
+                *curr_p = curr_p.wrapping_add(*prev_p);
-            }
+            });
-            for x in 0..width as usize {
+            curr_alpha.iter_mut().zip(&prev_alpha).for_each(|(curr_a, prev_a)| {
-                curr_alpha[x] = curr_alpha[x].wrapping_add(prev_alpha[x])
+                *curr_a = curr_a.wrapping_add(*prev_a);
-            }
+            });
         }
 
         for x in 0..width as usize {
-            picture.get_pixel_mut(x as u32, y).0 = [
+            let pos = x * 3;
-                curr_line[x * 3],
+            output_buf.extend_from_slice(&[
-                curr_line[x * 3 + 1],
+                curr_line[pos],
-                curr_line[x * 3 + 2],
+                curr_line[pos + 1],
+                curr_line[pos + 2],
                 curr_alpha[x],
-            ];
+            ]);
         }
 
         prev_line.clone_from(&curr_line);
         prev_alpha.clone_from(&curr_alpha);
-        i += width as usize * 3;
+        rgb_index += width as usize * 3;
-        z += width as usize;
+        alpha_index += width as usize;
     }
+
+    output_buf
 }
 
 fn diff_line(header: &CommonHeader, input: &[u8]) -> Vec<u8> {