From 4bf2e8f8bf0002f23f639aefce5f5162f6f183eb Mon Sep 17 00:00:00 2001
From: Abyr Valg <valga@abyrga.ru>
Date: Mon, 13 Apr 2020 07:31:17 +0300
Subject: [PATCH 1/2] Make sure that buffer is always a string

substr() returns false when offset is greater than total length.
---
 src/AesEncryptingStream.php | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/AesEncryptingStream.php b/src/AesEncryptingStream.php
index 97dfcdb..1322406 100644
--- a/src/AesEncryptingStream.php
+++ b/src/AesEncryptingStream.php
@@ -69,7 +69,11 @@ public function read($length): string
         }
 
         $data = substr($this->buffer, 0, $length);
-        $this->buffer = substr($this->buffer, $length);
+        if ($length < strlen($this->buffer)) {
+            $this->buffer = substr($this->buffer, $length);
+        } else {
+            $this->buffer = '';
+        }
 
         return $data ? $data : '';
     }

From 8fc77f6c46b0028905789ec195a162504c0c4342 Mon Sep 17 00:00:00 2001
From: Abyr Valg <valga@abyrga.ru>
Date: Sun, 12 Apr 2020 21:26:25 +0300
Subject: [PATCH 2/2] Make eof() consider padding when reading less than block
 size

---
 src/AesEncryptingStream.php       |  5 +++++
 tests/AesEncryptingStreamTest.php | 20 ++++++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/src/AesEncryptingStream.php b/src/AesEncryptingStream.php
index 1322406..d61b5ae 100644
--- a/src/AesEncryptingStream.php
+++ b/src/AesEncryptingStream.php
@@ -97,6 +97,11 @@ public function seek($offset, $whence = SEEK_SET): void
         }
     }
 
+    public function eof(): bool
+    {
+        return $this->stream->eof() && $this->buffer === '';
+    }
+
     private function encryptBlock(int $length): string
     {
         if ($this->stream->eof()) {
diff --git a/tests/AesEncryptingStreamTest.php b/tests/AesEncryptingStreamTest.php
index 201c6e9..af97dc3 100644
--- a/tests/AesEncryptingStreamTest.php
+++ b/tests/AesEncryptingStreamTest.php
@@ -216,4 +216,24 @@ public function seek(int $offset, int $whence = SEEK_SET): void {}
 
         $this->assertRegExp("/EncryptionFailedException: Unable to encrypt/", $error);
     }
+
+    /**
+     * @dataProvider cipherMethodProvider
+     *
+     * @param CipherMethod $cipherMethod
+     */
+    public function testEofShouldConsiderPaddingWhenReadSizeIsLessThenBlockSize(CipherMethod $cipherMethod)
+    {
+        $stream = new AesEncryptingStream(
+            new RandomByteStream(100),
+            self::KEY,
+            $cipherMethod
+        );
+        $expectedSize = $stream->getSize();
+        $actualSize = 0;
+        while (!$stream->eof()) {
+            $actualSize += strlen($stream->read(15));
+        }
+        $this->assertSame($expectedSize, $actualSize);
+    }
 }