src/thinkextend/image/driver/Gif.php
public function GIFGetByte($len)
    {
        $this->GIF_buffer = [];

        for ($i = 0; $i < $len; $i++) {
            if ($this->GIF_bfseek > strlen($this->GIF_stream)) {
                return 0;
            }
            $this->GIF_buffer[] = ord($this->GIF_stream{$this->GIF_bfseek++});
        }
        return 1;
    }
public function GIFGetByte($len)
    {
        $this->GIF_buffer = [];

        for ($i = 0; $i < $len; $i++) {
            if ($this->GIF_bfseek > strlen($this->GIF_stream)) {
                return 0;
            }
            $this->GIF_buffer[] = ord($this->GIF_stream{$this->GIF_bfseek++});
        }
        return 1;
    }
/*

05.06.2007.
Made a little modification


-    function GIFGetByte ( $len ) {
-        $this->GIF_buffer = array ( );
-
-        for ( $i = 0; $i < $len; $i++ ) {
+            if ( $this->GIF_bfseek > strlen ( $this->GIF_stream ) ) {
+                return 0;
+            }
-            $this->GIF_buffer [ ] = ord ( $this->GIF_stream { $this->GIF_bfseek++ } );
-        }
+        return 1;
-    }