Improved binio.rs, updated LZW decompressor

cz/src/binio.rs

@@ -1,8 +1,3 @@
-pub enum BitError {
-    InputLength
-}
-
-
 pub struct BitIo {
     data: Vec<u8>,
     byte_offset: usize,
@@ -40,7 +35,7 @@ impl BitIo {
     /// Read some bits from the buffer
     pub fn read_bit(&mut self, bit_len: usize) -> u64 {
         if bit_len > 8 * 8 {
-            panic!()
+            panic!("Cannot read more than 64 bits")
         }
 
         if bit_len % 8 == 0 && self.bit_offset == 0 {
@@ -66,7 +61,7 @@ impl BitIo {
     /// Read some bytes from the buffer
     pub fn read(&mut self, byte_len: usize) -> u64 {
         if byte_len > 8 {
-            panic!()
+            panic!("Cannot read more than 8 bytes")
         }
 
         let mut padded_slice = [0u8; 8];
@@ -79,7 +74,7 @@ impl BitIo {
     /// Write some bits to the buffer
     pub fn write_bit(&mut self, data: u64, bit_len: usize) {
         if bit_len > 8 * 8 {
-            panic!();
+            panic!("Cannot write more than 64 bits");
         }
 
         if bit_len % 8 == 0 && self.bit_offset == 0 {
@@ -104,9 +99,9 @@ impl BitIo {
         self.byte_size = self.byte_offset + (self.bit_offset + 7) / 8;
     }
 
-    pub fn write(&mut self, data: u64, byte_len: usize) -> Result<(), BitError> {
+    pub fn write(&mut self, data: u64, byte_len: usize) {
         if byte_len > 8 {
-            return Err(BitError::InputLength);
+            panic!("Cannot write more than 8 bytes")
         }
 
         let mut padded_slice = [0u8; 8];
@@ -117,7 +112,5 @@ impl BitIo {
         self.byte_offset += byte_len;
 
         self.byte_size = self.byte_offset + (self.bit_offset + 7) / 8;
-
-        Ok(())
     }
 }

cz/src/common.rs

@@ -156,10 +156,12 @@ impl CommonHeader {
         self.version
     }
 
-    pub fn set_version<I: TryInto<CzVersion>>(&mut self, version: I) -> Result<(), ()> {
+    pub fn set_version<I: TryInto<CzVersion>>(
+        &mut self, version: I
+    ) -> Result<(), Box<dyn std::error::Error>> {
         self.version = match version.try_into() {
             Ok(val) => val,
-            Err(_) => return Err(()),
+            Err(_) => return Err("Invalid CZ value".into()),
         };
 
         Ok(())

cz/src/compression.rs

@@ -27,7 +27,7 @@ pub struct CompressionInfo {
     pub total_size_compressed: usize,
 
     /// Total size of the original uncompressed data
-    pub total_size_raw: usize,
+    pub _total_size_raw: usize,
 
     /// The compression chunk information
     pub chunks: Vec<ChunkInfo>,
@@ -82,7 +82,7 @@ pub fn get_chunk_info<T: Seek + ReadBytesExt + Read>(
     Ok(CompressionInfo {
         chunk_count: parts_count as usize,
         total_size_compressed: total_size as usize,
-        total_size_raw: total_size_raw as usize,
+        _total_size_raw: total_size_raw as usize,
         chunks: part_sizes,
         length: bytes.stream_position()? as usize,
     })
@@ -93,70 +93,59 @@ pub fn decompress<T: Seek + ReadBytesExt + Read>(
     input: &mut T,
     chunk_info: &CompressionInfo,
 ) -> Result<Vec<u8>, CzError> {
-    let mut m_dst = 0;
+    let mut output_buf: Vec<u8> = vec![];
-    let mut bitmap = vec![0; chunk_info.total_size_raw];
-    for chunk in &chunk_info.chunks {
-        let mut part = vec![0u8; chunk.size_compressed * 2];
-        input.read_exact(&mut part)?;
 
-        for j in (0..part.len()).step_by(2) {
+    for block in &chunk_info.chunks {
-            let ctl = part[j + 1];
+        let mut buffer = vec![0u16; block.size_compressed];
 
-            if ctl == 0 {
+        for word in buffer.iter_mut() {
-                bitmap[m_dst] = part[j];
+            *word = input.read_u16::<LittleEndian>().unwrap();
-                m_dst += 1;
-            } else {
-                m_dst += copy_range(&mut bitmap, &part, get_offset(&part, j), m_dst);
-            }
         }
+
+        let raw_buf = decompress_lzw(&buffer, block.size_raw);
+
+        output_buf.write_all(&raw_buf)?;
     }
 
-    bitmap.truncate(chunk_info.total_size_raw);
+    Ok(output_buf)
-
-    Ok(bitmap)
 }
 
-fn get_offset(input: &[u8], src: usize) -> usize {
+fn decompress_lzw(
-    (((input[src] as usize) | (input[src + 1] as usize) << 8) - 0x101) * 2
+    input_data: &[u16],
-}
+    size: usize
-
+) -> Vec<u8> {
-fn copy_range(bitmap: &mut Vec<u8>, input: &[u8], src: usize, dst: usize) -> usize {
+    let mut dictionary: HashMap<u16, Vec<u8>> = HashMap::new();
-    let mut dst = dst;
+    for i in 0..256 {
-    let start_pos = dst;
+        dictionary.insert(i as u16, vec![i as u8]);
-
-    if input[src + 1] == 0 {
-        bitmap[dst] = input[src];
-        dst += 1;
-    } else if get_offset(input, src) == src {
-        bitmap[dst] = 0;
-        dst += 1;
-    } else {
-        dst += copy_range(bitmap, input, get_offset(input, src), dst);
     }
+    let mut dictionary_count = dictionary.len() as u16;
 
-    if input[src + 3] == 0 {
+    let mut w = vec![0];
-        bitmap[dst] = input[src + 2];
+    let mut result = Vec::with_capacity(size);
-        dst += 1;
-    } else if get_offset(input, src + 2) == src {
-        bitmap[dst] = bitmap[start_pos];
-        dst += 1;
-    } else {
-        bitmap[dst] = copy_one(input, get_offset(input, src + 2));
-        dst += 1;
-    }
 
-    dst - start_pos
+    input_data.iter().for_each(|element| {
+        let mut entry;
+        if let Some(x) = dictionary.get(element) {
+            entry = x.clone();
+        } else if *element == dictionary_count {
+            entry = w.clone();
+            entry.push(w[0]);
+        } else {
+            panic!("Bad compressed element: {}", element)
+        }
+
+        result.write_all(&entry).unwrap();
+        w.push(entry[0]);
+
+        dictionary.insert(dictionary_count, w.clone());
+        dictionary_count += 1;
+
+        w = entry;
+    });
+
+    result
 }
 
-fn copy_one(input: &[u8], src: usize) -> u8 {
-    if input[src + 1] == 0 {
-        input[src]
-    } else if get_offset(input, src) == src {
-        0
-    } else {
-        copy_one(input, get_offset(input, src))
-    }
-}
 
 /// Decompress an LZW compressed stream like CZ2
 pub fn decompress2<T: Seek + ReadBytesExt + Read>(
@@ -177,7 +166,10 @@ pub fn decompress2<T: Seek + ReadBytesExt + Read>(
     Ok(output_buf)
 }
 
-fn decompress_lzw2(input_data: &[u8], size: usize) -> Vec<u8> {
+fn decompress_lzw2(
+    input_data: &[u8],
+    size: usize
+) -> Vec<u8> {
     let mut data = input_data.to_vec();
     data[0] = 0;
     let mut dictionary = HashMap::new();
@@ -244,7 +236,7 @@ pub fn compress(
 
     let mut output_buf: Vec<u8> = vec![];
     let mut output_info = CompressionInfo {
-        total_size_raw: data.len(),
+        _total_size_raw: data.len(),
         ..Default::default()
     };
 
@@ -279,7 +271,11 @@ pub fn compress(
     (output_buf, output_info)
 }
 
-fn compress_lzw(data: &[u8], size: usize, last: Vec<u8>) -> (usize, Vec<u16>, Vec<u8>) {
+fn compress_lzw(
+    data: &[u8],
+    size: usize,
+    last: Vec<u8>
+) -> (usize, Vec<u16>, Vec<u8>) {
     let mut count = 0;
     let mut dictionary = HashMap::new();
     for i in 0..=255 {
@@ -331,7 +327,10 @@ fn compress_lzw(data: &[u8], size: usize, last: Vec<u8>) -> (usize, Vec<u16>, Ve
     (count, compressed, last_element)
 }
 
-pub fn compress2(data: &[u8], size: usize) -> (Vec<u8>, CompressionInfo) {
+pub fn compress2(
+    data: &[u8],
+    size: usize
+) -> (Vec<u8>, CompressionInfo) {
     let size = if size == 0 { 0x87BDF } else { size };
 
     let mut part_data;
@@ -342,7 +341,7 @@ pub fn compress2(data: &[u8], size: usize) -> (Vec<u8>, CompressionInfo) {
 
     let mut output_buf: Vec<u8> = Vec::new();
     let mut output_info = CompressionInfo {
-        total_size_raw: data.len(),
+        _total_size_raw: data.len(),
         ..Default::default()
     };
 
@@ -374,7 +373,11 @@ pub fn compress2(data: &[u8], size: usize) -> (Vec<u8>, CompressionInfo) {
     (output_buf, output_info)
 }
 
-fn compress_lzw2(data: &[u8], size: usize, last: Vec<u8>) -> (usize, Vec<u8>, Vec<u8>) {
+fn compress_lzw2(
+    data: &[u8],
+    size: usize,
+    last: Vec<u8>
+) -> (usize, Vec<u8>, Vec<u8>) {
     let mut data = data.to_vec();
     if !data.is_empty() {
         data[0] = 0;

cz/src/dynamic.rs

@@ -113,7 +113,7 @@ impl DynamicCz {
     /// to change the CZ# version.
     pub fn save_as_cz<T: Into<std::path::PathBuf>>(&self, path: T) -> Result<(), CzError> {
         let mut out_file = BufWriter::new(File::create(path.into())?);
-        let mut header = self.header().clone();
+        let mut header = *self.header();
 
         if header.version() == CzVersion::CZ2 {
             header.set_length(0x12)

cz/src/formats/cz3.rs

@@ -55,9 +55,9 @@ fn line_diff(header: &CommonHeader, data: &[u8]) -> Vec<u8> {
     let mut curr_line;
     let mut prev_line = Vec::with_capacity(line_byte_count);
 
-    let mut i = 0;
+    let mut index = 0;
     for y in 0..height {
-        curr_line = data[i..i + line_byte_count].to_vec();
+        curr_line = data[index..index + line_byte_count].to_vec();
 
         if y % block_height as u32 != 0 {
             curr_line.iter_mut().zip(&prev_line).for_each(|(curr_p, prev_p)| {
@@ -67,7 +67,7 @@ fn line_diff(header: &CommonHeader, data: &[u8]) -> Vec<u8> {
 
         prev_line.clone_from(&curr_line);
         if pixel_byte_count == 4 {
-            output_buf[i..i + line_byte_count].copy_from_slice(&curr_line);
+            output_buf[index..index + line_byte_count].copy_from_slice(&curr_line);
         } else if pixel_byte_count == 3 {
             for x in (0..line_byte_count).step_by(3) {
                 let loc = (y * 3 * width) as usize + x;
@@ -86,7 +86,7 @@ fn line_diff(header: &CommonHeader, data: &[u8]) -> Vec<u8> {
             }
         }
 
-        i += line_byte_count;
+        index += line_byte_count;
     }
 
     output_buf

cz/src/formats/cz4.rs

@@ -68,18 +68,23 @@ fn line_diff(header: &CommonHeader, data: &[u8]) -> Vec<u8> {
             });
         }
 
-        for x in 0..width as usize {
+        // Write the decoded RGBA data to the final buffer
-            let pos = x * 3;
+        curr_line
-            output_buf.extend_from_slice(&[
+            .windows(3)
-                curr_line[pos],
+            .step_by(3)
-                curr_line[pos + 1],
+            .zip(&curr_alpha)
-                curr_line[pos + 2],
+            .for_each(|(curr_p, alpha_p)| {
-                curr_alpha[x],
+                output_buf.extend_from_slice(&[
-            ]);
+                    curr_p[0],
-        }
+                    curr_p[1],
+                    curr_p[2],
+                    *alpha_p,
+                ]);
+            });
 
         prev_line.clone_from(&curr_line);
         prev_alpha.clone_from(&curr_alpha);
+
         rgb_index += width as usize * 3;
         alpha_index += width as usize;
     }