first commit

pma/vendor/fgrosse/phpasn1/lib/ASN1/Base128.php

@@ -0,0 +1,63 @@
+<?php
+
+namespace FG\ASN1;
+
+use FG\Utility\BigInteger;
+use InvalidArgumentException;
+
+/**
+ * A base-128 decoder.
+ */
+class Base128
+{
+    /**
+     * @param int $value
+     *
+     * @return string
+     */
+    public static function encode($value)
+    {
+        $value = BigInteger::create($value);
+        $octets = chr($value->modulus(0x80)->toInteger());
+
+        $value = $value->shiftRight(7);
+        while ($value->compare(0) > 0) {
+            $octets .= chr(0x80 | $value->modulus(0x80)->toInteger());
+            $value = $value->shiftRight(7);
+        }
+
+        return strrev($octets);
+    }
+
+    /**
+     * @param string $octets
+     *
+     * @throws InvalidArgumentException if the given octets represent a malformed base-128 value or the decoded value would exceed the the maximum integer length
+     *
+     * @return int
+     */
+    public static function decode($octets)
+    {
+        $bitsPerOctet = 7;
+        $value = BigInteger::create(0);
+        $i = 0;
+
+        while (true) {
+            if (!isset($octets[$i])) {
+                throw new InvalidArgumentException(sprintf('Malformed base-128 encoded value (0x%s).', strtoupper(bin2hex($octets)) ?: '0'));
+            }
+
+            $octet = ord($octets[$i++]);
+
+            $l1 = $value->shiftLeft($bitsPerOctet);
+            $r1 = $octet & 0x7f;
+            $value = $l1->add($r1);
+
+            if (0 === ($octet & 0x80)) {
+                break;
+            }
+        }
+
+        return (string)$value;
+    }
+}