Zanzarah: Fix unpacking (fixes #25)

Author: refaim

src/modules/zanzarah/zanzarah.cpp

@@ -65,17 +65,12 @@ namespace extractor
             const auto block_offset = read_positive_or_zero_int32(stream);
             const auto block_size = read_positive_int32(stream);
 
-            [[maybe_unused]] constexpr int32_t data_block_footer = 0x202;
-            [[maybe_unused]] constexpr int32_t data_block_header = 0x101;
-            constexpr int32_t header_size = sizeof(data_block_header);
-            constexpr int32_t footer_size = sizeof(data_block_footer);
+            constexpr int32_t attr_size = 4;
 
             auto new_file = std::make_unique<file>();
             new_file->path = path;
-            new_file->offset = block_offset + header_size;
-            // [0x101, data, 0x202], [0x101, data, 0x202], ...
-            // No idea why we should subtract next data block header, but apparently that's the right way
-            new_file->compressed_body_size_in_bytes = block_size - 2 * header_size - footer_size;
+            new_file->offset = block_offset + attr_size;
+            new_file->compressed_body_size_in_bytes = block_size - attr_size;
             new_file->uncompressed_body_size_in_bytes = new_file->compressed_body_size_in_bytes;
 
             files.push_back(std::move(new_file));