--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rust/hedgewars-server/src/core/digest.rs	Sat Feb 22 19:39:31 2025 +0300
@@ -0,0 +1,55 @@
+use rand::{thread_rng, RngCore};
+use std::fmt::{Formatter, LowerHex};
+
+#[derive(PartialEq, Debug)]
+pub struct Sha1Digest([u8; 20]);
+
+impl Sha1Digest {
+    pub fn new(digest: [u8; 20]) -> Self {
+        Self(digest)
+    }
+
+    pub fn random() -> Self {
+        let mut result = Sha1Digest(Default::default());
+        thread_rng().fill_bytes(&mut result.0);
+        result
+    }
+}
+
+impl LowerHex for Sha1Digest {
+    fn fmt(&self, f: &mut Formatter) -> Result<(), std::fmt::Error> {
+        for byte in &self.0 {
+            write!(f, "{:02x}", byte)?;
+        }
+        Ok(())
+    }
+}
+
+impl PartialEq<&str> for Sha1Digest {
+    fn eq(&self, other: &&str) -> bool {
+        if other.len() != self.0.len() * 2 {
+            false
+        } else {
+            #[inline]
+            fn convert(c: u8) -> u8 {
+                if c > b'9' {
+                    c.wrapping_sub(b'a').saturating_add(10)
+                } else {
+                    c.wrapping_sub(b'0')
+                }
+            }
+
+            other
+                .as_bytes()
+                .chunks_exact(2)
+                .zip(&self.0)
+                .all(|(chars, byte)| {
+                    if let [hi, lo] = chars {
+                        convert(*lo) == byte & 0x0f && convert(*hi) == (byte & 0xf0) >> 4
+                    } else {
+                        unreachable!()
+                    }
+                })
+        }
+    }
+}