Add toWei and bignumber

composer.json

@@ -13,7 +13,8 @@
     "require": {
         "guzzlehttp/guzzle": "~6.0",
         "PHP": "^7.1",
-        "kornrunner/keccak": "dev-master"
+        "kornrunner/keccak": "dev-master",
+        "phpseclib/phpseclib": "dev-master"
     },
     "require-dev": {
         "phpunit/phpunit": "~6.0"

src/Utils.php

@@ -13,6 +13,7 @@ namespace Web3;
 
 use InvalidArgumentException;
 use kornrunner\Keccak;
+use phpseclib\Math\BigInteger as BigNumber;
 
 class Utils
 {
@@ -23,6 +24,42 @@ class Utils
      */
     const SHA3_NULL_HASH = 'c5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470';
 
+    /**
+     * UNITS
+     * from web3.js
+     * 
+     * @const array
+     */
+    const UNITS = [
+        'noether' => '0',
+        'wei' => '1',
+        'kwei' => '1000',
+        'Kwei' => '1000',
+        'babbage' => '1000',
+        'femtoether' => '1000',
+        'mwei' => '1000000',
+        'Mwei' => '1000000',
+        'lovelace' => '1000000',
+        'picoether' => '1000000',
+        'gwei' => '1000000000',
+        'Gwei' => '1000000000',
+        'shannon' => '1000000000',
+        'nanoether' => '1000000000',
+        'nano' => '1000000000',
+        'szabo' => '1000000000000',
+        'microether' => '1000000000000',
+        'micro' => '1000000000000',
+        'finney' => '1000000000000000',
+        'milliether' => '1000000000000000',
+        'milli' => '1000000000000000',
+        'ether' => '1000000000000000000',
+        'kether' => '1000000000000000000000',
+        'grand' => '1000000000000000000000',
+        'mether' => '1000000000000000000000000',
+        'gether' => '1000000000000000000000000000',
+        'tether' => '1000000000000000000000000000000'
+    ];
+
     /**
      * construct
      *
@@ -120,4 +157,34 @@ class Utils
         }
         return '0x' . $hash;
     }
+
+    /**
+     * toWei
+     * 
+     * @param BigNumber|string|int $number
+     * @param string $unit
+     * @return string
+     */
+    public static function toWei($number, $unit)
+    {
+        if (is_int($number)) {
+            $bn = new BigNumber($number);
+        } elseif (is_string($number)) {
+            if (self::isZeroPrefixed($number)) {
+                $number = self::stripZero($number);
+            }
+            $bn = new BigNumber($number, 16);
+        } elseif (!$number instanceof BigNumber){
+            throw new InvalidArgumentException('toWei number must be BigNumber, string or int.');
+        }
+        if (!is_string($unit)) {
+            throw new InvalidArgumentException('toWei unit must be string.');
+        }
+        if (!isset(self::UNITS[$unit])) {
+            throw new InvalidArgumentException('toWei doesn\'t support ' . $unit . ' unit.');
+        }
+        $bnt = new BigNumber(self::UNITS[$unit]);
+
+        return $bn->multiply($bnt);
+    }
 }

test/unit/UtilsTest.php

@@ -110,4 +110,32 @@ class UtilsTest extends TestCase
 
         $this->assertEquals(mb_substr($str, 0, 10), '0xcdcd77c0');
     }
+
+    /**
+     * testToWei
+     * 
+     * @return void
+     */
+    public function testToWei()
+    {
+        $bn = Utils::toWei('0x1', 'wei');
+
+        $this->assertEquals($bn->toString(), '1');
+
+        $bn = Utils::toWei('1', 'wei');
+
+        $this->assertEquals($bn->toString(), '1');
+
+        $bn = Utils::toWei(1, 'wei');
+
+        $this->assertEquals($bn->toString(), '1');
+
+        $bn = Utils::toWei('1', 'ether');
+
+        $this->assertEquals($bn->toString(), '1000000000000000000');
+
+        $bn = Utils::toWei('0x5218', 'wei');
+
+        $this->assertEquals($bn->toString(), '21016');
+    }
 }