по замечаниям: контроль null, отрицательный счетчик, закрытие потока

Author: Mr-Rm

src/OneScript.StandardLibrary/Hash/HashImpl.cs

@@ -34,10 +34,11 @@ public HashImpl(IncrementalHash provider, HashFunctionEnum enumValue)
             _provider = provider;
             _enumValue = enumValue;
             _calculated = false;
-            if (enumValue == HashFunctionEnum.CRC32 || provider==null)
+            if (enumValue == HashFunctionEnum.CRC32)
             {
                 _crc32 = new Crc32();
             }
+            else ArgumentNullException.ThrowIfNull(provider);
         }
 
         [ContextProperty("ХешФункция", "HashFunction")]
@@ -63,6 +64,9 @@ public string HashString
         {
             get
             {
+                if (!_calculated)
+                    return "0";
+
                 if (_crc32 != null)
                     return _crc32.GetCurrentHashAsUInt32().ToString("X8");
 
@@ -132,10 +136,10 @@ public void Append(BslValue toAdd, int count = 0)
                     break;
                 case IStreamWrapper wrapper:
                     var stream = wrapper.GetUnderlyingStream();
-                    if (count == 0)
+                    if (count <= 0)
                         AppendStream(stream);
                     else
-                        AppendStream(stream, count);
+                    AppendStream(stream, count);
                     break;
                 case BinaryDataContext binaryData:
                     AppendStream(binaryData.GetStream());
@@ -149,10 +153,10 @@ public void Append(BslValue toAdd, int count = 0)
         public void AppendFile(string path)
         {
             if (!File.Exists(path))
-                throw RuntimeException.InvalidArgumentType();
-            var stream = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
-            AppendStream(stream);
-            stream.Close();
+                throw RuntimeException.InvalidArgumentType();
+
+            using var stream = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
+            AppendStream(stream);
         }
 
         [ScriptConstructor(Name = "По указанной хеш-функции")]