feat(php-shim): implement round() shim

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

1 files changed, 13 insertions, 16 deletions

diff --git a/crates/shirabe-php-shim/src/math.rs b/crates/shirabe-php-shim/src/math.rs
index fffe2d6..ee9a76d 100644
--- a/crates/shirabe-php-shim/src/math.rs
+++ b/crates/shirabe-php-shim/src/math.rs
@@ -1,33 +1,30 @@
-pub fn max_i64(_a: i64, _b: i64) -> i64 {
-    _a.max(_b)
+pub fn max(a: i64, b: i64) -> i64 {
+    a.max(b)
 }
 
-pub fn max(_a: i64, _b: i64) -> i64 {
-    _a.max(_b)
+pub fn min(a: i64, b: i64) -> i64 {
+    a.min(b)
 }
 
-pub fn min(_a: i64, _b: i64) -> i64 {
-    _a.min(_b)
+pub fn abs(v: i64) -> i64 {
+    v.abs()
 }
 
-pub fn abs(_value: i64) -> i64 {
-    _value.abs()
-}
-
-pub fn floor(_value: f64) -> f64 {
-    _value.floor()
+pub fn floor(v: f64) -> f64 {
+    v.floor()
 }
 
 pub fn ceil(v: f64) -> f64 {
     v.ceil()
 }
 
-pub fn round(_value: f64, _precision: i64) -> f64 {
-    todo!()
+pub fn round(v: f64, precision: i64) -> f64 {
+    // PHP's default mode is PHP_ROUND_HALF_UP (round half away from zero),
+    // which matches Rust's f64::round.
+    let factor = 10f64.powi(precision as i32);
+    (v * factor).round() / factor
 }
 
 pub fn intdiv(a: i64, b: i64) -> i64 {
-    // PHP intdiv() throws DivisionByZeroError on a zero divisor and ArithmeticError
-    // for PHP_INT_MIN / -1; Rust's `/` likewise panics in both cases.
     a / b
 }