From 677ae387b0a24530bc7c5d43d94dc333bdfaf099 Mon Sep 17 00:00:00 2001
From: terrafrost <terrafrost@php.net>
Date: Sun, 26 May 2019 15:38:18 -0500
Subject: [PATCH] BigInteger: backport GMP fixes from master branch

---
 phpseclib/Math/BigInteger.php           | 2 +-
 tests/Unit/Math/BigInteger/TestCase.php | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/phpseclib/Math/BigInteger.php b/phpseclib/Math/BigInteger.php
index 1807e4aa..9d41a5c2 100644
--- a/phpseclib/Math/BigInteger.php
+++ b/phpseclib/Math/BigInteger.php
@@ -441,7 +441,7 @@ class Math_BigInteger
                 // (?<=^|-)0*: find any 0's that are preceded by the start of the string or by a - (ie. octals)
                 // [^-0-9].*: find any non-numeric characters and then any characters that follow that
                 $x = preg_replace('#(?<!^)(?:-).*|(?<=^|-)0*|[^-0-9].*#', '', $x);
-                if (!strlen($x)) {
+                if (!strlen($x) || $x == '-') {
                     $x = '0';
                 }
 
diff --git a/tests/Unit/Math/BigInteger/TestCase.php b/tests/Unit/Math/BigInteger/TestCase.php
index 103b5c6a..d6985fd3 100644
--- a/tests/Unit/Math/BigInteger/TestCase.php
+++ b/tests/Unit/Math/BigInteger/TestCase.php
@@ -414,5 +414,8 @@ abstract class Unit_Math_BigInteger_TestCase extends PhpseclibTestCase
     {
         $temp = $this->getInstance('00');
         $this->assertSame($temp->toString(), '0');
+
+        $temp = $this->getInstance('-0');
+        $this->assertSame($temp->toString(), '0');
     }
 }