feat: new chain

app/Services/Chain/EthRlp.php

@@ -0,0 +1,66 @@
+<?php
+
+namespace App\Services\Chain;
+
+/**
+ * Minimal RLP encoder for legacy Ethereum transactions.
+ */
+final class EthRlp
+{
+    /**
+     * @param  list<string|list<mixed>>  $list  binary strings or nested lists
+     */
+    public static function encodeList(array $list): string
+    {
+        $payload = '';
+        foreach ($list as $item) {
+            $payload .= is_array($item) ? self::encodeList($item) : self::encodeString($item);
+        }
+
+        return self::encodeLength(strlen($payload), 0xc0).$payload;
+    }
+
+    public static function encodeString(string $input): string
+    {
+        $len = strlen($input);
+        if ($len === 1 && ord($input) < 0x80) {
+            return $input;
+        }
+
+        return self::encodeLength($len, 0x80).$input;
+    }
+
+    /** Integer → minimal big-endian binary (empty for zero). */
+    public static function intToBin(string|int $value): string
+    {
+        if (is_int($value)) {
+            $value = (string) $value;
+        }
+        if (! preg_match('/^\d+$/', $value)) {
+            throw new \InvalidArgumentException('Invalid integer');
+        }
+        if (bccomp($value, '0') === 0) {
+            return '';
+        }
+        $hex = gmp_strval(gmp_init($value, 10), 16);
+        if (strlen($hex) % 2 !== 0) {
+            $hex = '0'.$hex;
+        }
+
+        return hex2bin($hex) ?: '';
+    }
+
+    private static function encodeLength(int $len, int $offset): string
+    {
+        if ($len < 56) {
+            return chr($len + $offset);
+        }
+        $hex = dechex($len);
+        if (strlen($hex) % 2 !== 0) {
+            $hex = '0'.$hex;
+        }
+        $bin = hex2bin($hex) ?: '';
+
+        return chr(strlen($bin) + $offset + 55).$bin;
+    }
+}