Yaz0 bugfix (#15)

* Fix Yaz0 issue of adding extra zero sometimes

* Cleanup

* changelog

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+
+- Fix some rare cases where the Yaz0 compressor may append an extra 0 at the end of the compressed data.
+
 ## [0.3.0] - 2024-1-19
 
 ### Added
@@ -42,7 +46,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Python bindings.
 - C bindings.
 
-[unreleased]: https://github.com/decompals/crunch64/compare/0.2.0...HEAD
+[unreleased]: https://github.com/decompals/crunch64/compare/0.3.0...HEAD
+[0.3.0]: https://github.com/decompals/crunch64/compare/0.2.0...0.3.0
 [0.2.0]: https://github.com/decompals/crunch64/compare/0.1.1...0.2.0
 [0.1.1]: https://github.com/decompals/crunch64/compare/0.1.0...0.1.1
 [0.1.0]: https://github.com/decompals/crunch64/releases/tag/0.1.0

lib/src/yaz0.rs

@@ -100,13 +100,22 @@ pub fn compress(bytes: &[u8]) -> Result<Box<[u8]>, Crunch64Error> {
 
     write_header(&mut output, input_size)?;
 
-    output.push(0);
     let mut index_cur_layout_byte: usize = 0x10;
-    let mut index_out_ptr: usize = index_cur_layout_byte + 1;
+    let mut index_out_ptr: usize = index_cur_layout_byte;
     let mut input_pos: usize = 0;
-    let mut cur_layout_bit: u8 = 0x80;
+    let mut cur_layout_bit: u8 = 1;
 
     while input_pos < input_size {
+        // Advance to the next layout bit
+        cur_layout_bit >>= 1;
+
+        if cur_layout_bit == 0 {
+            cur_layout_bit = 0x80;
+            index_cur_layout_byte = index_out_ptr;
+            output.push(0);
+            index_out_ptr += 1;
+        }
+
         let (mut group_pos, mut group_size) = utils::search(input_pos, bytes, 0x111);
 
         // If the group isn't larger than 2 bytes, copying the input without compression is smaller
@@ -166,16 +175,6 @@ pub fn compress(bytes: &[u8]) -> Result<Box<[u8]>, Crunch64Error> {
             // Move forward in the input by the size of the group
             input_pos += group_size as usize;
         }
-
-        // Advance to the next layout bit
-        cur_layout_bit >>= 1;
-
-        if cur_layout_bit == 0 {
-            cur_layout_bit = 0x80;
-            index_cur_layout_byte = index_out_ptr;
-            output.push(0);
-            index_out_ptr += 1;
-        }
     }
 
     Ok(output.into_boxed_slice())