From fadf080cce878db9dd28af1997883d96ef0ef779 Mon Sep 17 00:00:00 2001
From: Benjamin Morel <benjamin.morel@gmail.com>
Date: Tue, 18 Aug 2020 18:28:24 +0200
Subject: [PATCH] Fix bug in BigInteger::toBytes()

---
 src/BigInteger.php       | 18 ++++++++++++------
 tests/BigIntegerTest.php | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+), 6 deletions(-)

diff --git a/src/BigInteger.php b/src/BigInteger.php
index 1d53da0..5607560 100644
--- a/src/BigInteger.php
+++ b/src/BigInteger.php
@@ -1092,18 +1092,24 @@ public function toBytes(bool $signed = true) : string
             throw new NegativeNumberException('Cannot convert a negative number to a byte string when $signed is false.');
         }
 
-        $pad = function(string $hex) : string {
-            return (strlen($hex) % 2 !== 0) ? '0' . $hex : $hex;
-        };
-
         $hex = $this->abs()->toBase(16);
-        $hex = $pad($hex);
+
+        if (strlen($hex) % 2 !== 0) {
+            $hex = '0' . $hex;
+        }
+
+        $baseHexLength = strlen($hex);
 
         if ($signed) {
             if ($this->isNegative()) {
                 $hex = bin2hex(~hex2bin($hex));
                 $hex = self::fromBase($hex, 16)->plus(1)->toBase(16);
-                $hex = $pad($hex);
+
+                $hexLength = strlen($hex);
+
+                if ($hexLength < $baseHexLength) {
+                    $hex = str_repeat('0', $baseHexLength - $hexLength) . $hex;
+                }
 
                 if ($hex[0] < '8') {
                     $hex = 'FF' . $hex;
diff --git a/tests/BigIntegerTest.php b/tests/BigIntegerTest.php
index c6c4f1d..b4b55e0 100644
--- a/tests/BigIntegerTest.php
+++ b/tests/BigIntegerTest.php
@@ -3519,9 +3519,37 @@ public function testToBytes(string $number, bool $signed, string $expectedByteSt
     public function providerToBytes() : array
     {
         return [
+            ['-549755813889', true, 'FF7FFFFFFFFF'],
+            ['-549755813888', true, '8000000000'],
+            ['-549755813887', true, '8000000001'],
+            ['-4294967297', true, 'FEFFFFFFFF'],
+            ['-4294967296', true, 'FF00000000'],
+            ['-4294967295', true, 'FF00000001'],
+            ['-4294836226', true, 'FF0001FFFE'],
+            ['-4294836225', true, 'FF0001FFFF'],
+            ['-4294836224', true, 'FF00020000'],
+            ['-4294836223', true, 'FF00020001'],
+            ['-2147483650', true, 'FF7FFFFFFE'],
+            ['-2147483649', true, 'FF7FFFFFFF'],
+            ['-2147483648', true, '80000000'],
+            ['-16777217', true, 'FEFFFFFF'],
+            ['-16777216', true, 'FF000000'],
+            ['-16777215', true, 'FF000001'],
+            ['-16777214', true, 'FF000002'],
+            ['-16776961', true, 'FF0000FF'],
+            ['-16776960', true, 'FF000100'],
+            ['-16776959', true, 'FF000101'],
+            ['-131073', true, 'FDFFFF'],
+            ['-131072', true, 'FE0000'],
+            ['-131071', true, 'FE0001'],
+            ['-65537', true, 'FEFFFF'],
+            ['-65536', true, 'FF0000'],
+            ['-65535', true, 'FF0001'],
             ['-32769', true, 'FF7FFF'],
             ['-32768', true, '8000'],
             ['-32767', true, '8001'],
+            ['-256', true, 'FF00'],
+            ['-255', true, 'FF01'],
             ['-129', true, 'FF7F'],
             ['-128', true, '80'],
             ['-2', true, 'FE'],
@@ -3534,10 +3562,18 @@ public function providerToBytes() : array
             ['127', true, '7F'],
             ['128', false, '80'],
             ['128', true, '0080'],
+            ['255', false, 'FF'],
+            ['255', true, '00FF'],
             ['32767', false, '7FFF'],
             ['32767', true, '7FFF'],
             ['32768', false, '8000'],
             ['32768', true, '008000'],
+            ['65535', true, '00FFFF'],
+            ['65535', false, 'FFFF'],
+            ['8388607', false, '7FFFFF'],
+            ['8388607', true, '7FFFFF'],
+            ['16777215', false, 'FFFFFF'],
+            ['16777215', true, '00FFFFFF'],
 
             ['-783409810830859048059', true, 'D588013FBB7EADEB85'],
             ['3938956672038786165637', false, 'D588013FBB7EADEB85'],