bencher_fingerprint

Author: epompeii

Cargo.lock

@@ -26,6 +26,7 @@ bencher_adapter = { path = "lib/bencher_adapter" }
 bencher_boundary = { path = "lib/bencher_boundary" }
 bencher_client = { path = "lib/bencher_client" }
 bencher_comment = { path = "lib/bencher_comment" }
+bencher_fingerprint = { path = "lib/bencher_fingerprint" }
 bencher_github = { path = "lib/bencher_github" }
 bencher_json = { path = "lib/bencher_json" }
 bencher_logger = { path = "lib/bencher_logger" }

Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "bencher_fingerprint"
+homepage.workspace = true
+version.workspace = true
+authors.workspace = true
+edition.workspace = true
+license-file.workspace = true
+
+[dependencies]
+
+[lints]
+workspace = true

lib/bencher_fingerprint/Cargo.toml

@@ -0,0 +1,5 @@
+// #[cfg(target_os = "linux")]
+mod linux;
+
+// #[cfg(target_os = "linux")]
+// pub use linus::Fingerprint;

lib/bencher_fingerprint/src/lib.rs

@@ -0,0 +1,94 @@
+use std::iter::successors;
+use std::{fmt, fs};
+
+const HEX_BASE: u32 = 16;
+const BASE: u128 = 36;
+const BUF_SIZE: usize = 25;
+
+pub struct Fingerprint(u128);
+
+impl Fingerprint {
+    pub fn new() -> Option<Self> {
+        fs::read_to_string("/etc/machine-id")
+            .ok()
+            .and_then(|id| u128::from_str_radix(&id, HEX_BASE).ok())
+            .map(Self)
+    }
+}
+
+impl fmt::Display for Fingerprint {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let mut buffer = [0u8; BUF_SIZE];
+
+        let divided = successors(Some(self.0), |n| match n / BASE {
+            0 => None,
+
+            n => Some(n),
+        });
+
+        let written = buffer
+            .iter_mut()
+            .rev()
+            .zip(divided)
+            .map(|(c, n)| *c = digit((n % BASE) as u8, f.alternate()))
+            .count();
+
+        let index = BUF_SIZE - written;
+        let number = buffer.get(index..).unwrap_or_default();
+
+        // There are only ASCII chars inside the buffer,
+        // so the string should always be a valid UTF-8 string.
+        let number_str = std::str::from_utf8(number).unwrap_or_default();
+
+        f.write_str(number_str)
+    }
+}
+
+#[inline]
+fn digit(u: u8, alternate: bool) -> u8 {
+    let a = if alternate { b'A' } else { b'a' };
+    match u {
+        0..=9 => u + b'0',
+        10..=35 => u - 10 + a,
+        _ => {
+            debug_assert!(false, "Digit is greater than base {BASE}");
+            b'0'
+        },
+    }
+}
+
+#[allow(clippy::unreadable_literal)]
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_fingerprint_display() {
+        let fingerprint = Fingerprint(0x1234567890abcdef1234567890abcdef);
+        let display = format!("{fingerprint}");
+        assert_eq!(display, "12srde1xpfeunnr6aa7s0b4z3");
+
+        let fingerprint = Fingerprint(0xffffffffffffffffffffffffffffffff);
+        let display = format!("{fingerprint}");
+        assert_eq!(display, "f5lxx1zz5pnorynqglhzmsp33");
+
+        let fingerprint = Fingerprint(0);
+        let display = format!("{fingerprint}");
+        assert_eq!(display, "0");
+    }
+
+    #[test]
+    fn test_fingerprint_display_alternate() {
+        let fingerprint = Fingerprint(0x1234567890abcdef1234567890abcdef);
+        let display = format!("{fingerprint:#}");
+        assert_eq!(display, "12SRDE1XPFEUNNR6AA7S0B4Z3");
+
+        let fingerprint = Fingerprint(0xffffffffffffffffffffffffffffffff);
+        let display = format!("{fingerprint:#}");
+        assert_eq!(display, "F5LXX1ZZ5PNORYNQGLHZMSP33");
+
+        let fingerprint = Fingerprint(0);
+        let display = format!("{fingerprint:#}");
+        assert_eq!(display, "0");
+    }
+}