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>

2 files changed, 34 insertions, 8 deletions

diff --git a/crates/shirabe-php-shim/src/lib.rs b/crates/shirabe-php-shim/src/lib.rs
index 2a6ecf6..c236727 100644
--- a/crates/shirabe-php-shim/src/lib.rs
+++ b/crates/shirabe-php-shim/src/lib.rs
@@ -1,6 +1,8 @@
 mod preg;
+mod random;
 
 pub use preg::*;
+pub use random::*;
 
 use indexmap::IndexMap;
 
@@ -1360,10 +1362,6 @@ pub fn filesize(_path: &str) -> Option<i64> {
     std::fs::metadata(_path).ok().map(|m| m.len() as i64)
 }
 
-pub fn random_int(_min: i64, _max: i64) -> i64 {
-    todo!()
-}
-
 pub fn json_encode_ex<T: serde::Serialize + ?Sized>(_value: &T, _flags: i64) -> Option<String> {
     todo!()
 }
@@ -1607,10 +1605,6 @@ pub fn bin2hex(_data: &[u8]) -> String {
     _data.iter().map(|b| format!("{:02x}", b)).collect()
 }
 
-pub fn random_bytes(_length: usize) -> Vec<u8> {
-    todo!()
-}
-
 pub fn is_dir(_path: &str) -> bool {
     std::path::Path::new(_path).is_dir()
 }
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);