rust: syn: import crate

This is a subset of the Rust `syn` crate, version 2.0.58, licensed under "Apache-2.0 OR MIT", from: https://github.com/dtolnay/syn/raw/2.0.58/src The files are copied as-is, with no modifications whatsoever (not even adding the SPDX identifiers). For copyright details, please see: https://github.com/dtolnay/syn/blob/2.0.58/README.md#license https://github.com/dtolnay/syn/blob/2.0.58/LICENSE-APACHE https://github.com/dtolnay/syn/blob/2.0.58/LICENSE-MIT The next two patches modify these files as needed for use within the kernel. This patch split allows reviewers to double-check the import and to clearly see the differences introduced. The following script may be used to verify the contents: for path in $(cd rust/syn/ && find . -type f -name '*.rs'); do curl --silent --show-error --location \ https://github.com/dtolnay/syn/raw/2.0.58/src/$path \ | diff --unified rust/syn/$path - && echo $path: OK done Signed-off-by: Miguel Ojeda <[email protected]>
Rust-for-Linux · BennoLossin · Apr 7, 2024 · Apr 7, 2024 · Apr 10, 2024 · Oct 9, 2022
commit 328f151cbd3ab657ff9707a8b02ac3f68d3ac763
diff --git a/rust/syn/attr.rs b/rust/syn/attr.rs
diff --git a/rust/syn/bigint.rs b/rust/syn/bigint.rs
@@ -0,0 +1,66 @@
+use std::ops::{AddAssign, MulAssign};
+
+// For implementing base10_digits() accessor on LitInt.
+pub(crate) struct BigInt {
+    digits: Vec<u8>,
+}
+
+impl BigInt {
+    pub(crate) fn new() -> Self {
+        BigInt { digits: Vec::new() }
+    }
+
+    pub(crate) fn to_string(&self) -> String {
+        let mut repr = String::with_capacity(self.digits.len());
+
+        let mut has_nonzero = false;
+        for digit in self.digits.iter().rev() {
+            has_nonzero |= *digit != 0;
+            if has_nonzero {
+                repr.push((*digit + b'0') as char);
+            }
+        }
+
+        if repr.is_empty() {
+            repr.push('0');
+        }
+
+        repr
+    }
+
+    fn reserve_two_digits(&mut self) {
+        let len = self.digits.len();
+        let desired =
+            len + !self.digits.ends_with(&[0, 0]) as usize + !self.digits.ends_with(&[0]) as usize;
+        self.digits.resize(desired, 0);
+    }
+}
+
+impl AddAssign<u8> for BigInt {
+    // Assumes increment <16.
+    fn add_assign(&mut self, mut increment: u8) {
+        self.reserve_two_digits();
+
+        let mut i = 0;
+        while increment > 0 {
+            let sum = self.digits[i] + increment;
+            self.digits[i] = sum % 10;
+            increment = sum / 10;
+            i += 1;
+        }
+    }
+}
+
+impl MulAssign<u8> for BigInt {
+    // Assumes base <=16.
+    fn mul_assign(&mut self, base: u8) {
+        self.reserve_two_digits();
+
+        let mut carry = 0;
+        for digit in &mut self.digits {
+            let prod = *digit * base + carry;
+            *digit = prod % 10;
+            carry = prod / 10;
+        }
+    }
+}