1 files changed, 46 insertions, 0 deletions
diff --git a/vendor/clap-3.2.20/src/util/fnv.rs b/vendor/clap-3.2.20/src/util/fnv.rs
new file mode 100644
index 000000000..4602300a4
--- /dev/null
+++ b/vendor/clap-3.2.20/src/util/fnv.rs
@@ -0,0 +1,46 @@
+use std::{
+    fmt::Display,
+    hash::{Hash, Hasher},
+};
+
+const MAGIC_INIT: u64 = 0x811C_9DC5;
+
+// TODO: Docs
+pub trait Key: Hash + Display {
+    fn key(&self) -> u64;
+}
+
+impl<T> Key for T
+where
+    T: Hash + Display,
+{
+    fn key(&self) -> u64 {
+        let mut hasher = FnvHasher::new();
+        self.hash(&mut hasher);
+        hasher.finish()
+    }
+}
+
+pub(crate) struct FnvHasher(u64);
+
+impl FnvHasher {
+    pub(crate) fn new() -> Self {
+        FnvHasher(MAGIC_INIT)
+    }
+}
+
+impl Hasher for FnvHasher {
+    fn finish(&self) -> u64 {
+        self.0
+    }
+    fn write(&mut self, bytes: &[u8]) {
+        let FnvHasher(mut hash) = *self;
+
+        for byte in bytes.iter() {
+            hash ^= u64::from(*byte);
+            hash = hash.wrapping_mul(0x0100_0000_01b3);
+        }
+
+        *self = FnvHasher(hash);
+    }
+}