Add support to pack xp3 files

src/scripts/kirikiri/archive/xp3pack/reader.rs

@@ -0,0 +1,28 @@
+use adler::Adler32;
+use std::io::{PipeReader, Read};
+
+pub struct Reader {
+    inner: PipeReader,
+    adler: Adler32,
+}
+
+impl Reader {
+    pub fn new(inner: PipeReader) -> Self {
+        Self {
+            inner,
+            adler: Adler32::new(),
+        }
+    }
+
+    pub fn into_checksum(self) -> u32 {
+        self.adler.checksum()
+    }
+}
+
+impl Read for Reader {
+    fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
+        let n = self.inner.read(buf)?;
+        self.adler.write_slice(&buf[..n]);
+        Ok(n)
+    }
+}