feat(php-shim): implement random_int/random_bytes with fastrand

PHP's random_int/random_bytes are cryptographically secure, but Composer
does not rely on that property, so a non-cryptographic PRNG suffices.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/crates/shirabe-php-shim/src/random.rs b/crates/shirabe-php-shim/src/random.rs
new file mode 100644
index 0000000..05f62bd
--- /dev/null
+++ b/crates/shirabe-php-shim/src/random.rs
@@ -0,0 +1,32 @@
+//! PHP's `random_int()` and `random_bytes()` are cryptographically secure;
+//! these are not. Composer does not rely on that property, so a
+//! non-cryptographic PRNG is sufficient here.
+
+pub fn random_int<T: RandomInt>(range: impl std::ops::RangeBounds<T>) -> T {
+    T::random_int(range)
+}
+
+pub fn random_bytes(len: usize) -> Vec<u8> {
+    let mut buf = vec![0u8; len];
+    fastrand::fill(&mut buf);
+    buf
+}
+
+/// Integral types for which [`random_int`] can generate a value.
+pub trait RandomInt: Sized {
+    fn random_int(range: impl std::ops::RangeBounds<Self>) -> Self;
+}
+
+macro_rules! impl_random_int {
+    ($($t:ident),* $(,)?) => {
+        $(
+            impl RandomInt for $t {
+                fn random_int(range: impl std::ops::RangeBounds<Self>) -> Self {
+                    fastrand::$t(range)
+                }
+            }
+        )*
+    };
+}
+
+impl_random_int!(i8, i16, i32, i64, isize, u8, u16, u32, u64, usize);