1 files changed, 36 insertions, 0 deletions
diff --git a/src/Constant.php b/src/Constant.php
new file mode 100644
index 0000000..6cd63a7
--- /dev/null
+++ b/src/Constant.php
@@ -0,0 +1,36 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Zhineng\Snowflake;
+
+final class Constant extends Field
+{
+    use Makable;
+
+    public function __construct(
+        string $name,
+        int $bits,
+        public readonly int $value = 0
+    ) {
+        parent::__construct($name, $bits);
+
+        if ($this->value < 0) {
+            throw new \InvalidArgumentException('Field value must be non-negative.');
+        }
+
+        if ($this->value > $this->maxValue()) {
+            throw new \InvalidArgumentException(sprintf(
+                'Field value %d exceeds maximum %d for %d bits.',
+                $this->value,
+                $this->maxValue(),
+                $this->bits
+            ));
+        }
+    }
+
+    public function value(): int
+    {
+        return $this->value;
+    }
+}