Changeset 341 for CoolStreaming/UVarBlockSerializer.pas

Timestamp:

Apr 3, 2012, 7:32:43 AM (13 years ago)

Author:

chronos

Message:

• Modified: CoolStreaming VarBlockSerializer enhanced to better decode invalid data.

File:

• CoolStreaming/UVarBlockSerializer.pas (modified) (4 diffs)

CoolStreaming/UVarBlockSerializer.pas

@@ -110 +110 @@
   SUInt64Overflow = '64-bit UInt read overflow.';
   SReadError = 'Stream read error. Expected length %d, read %d. Source stream size %d.';
+  SErrorGetVarSize = 'Error reading variable block size';
 
 { TVarBlockSerializer }
@@ -416 +417 @@
   StoredPosition: Integer;
 begin
-  StoredPosition := Stream.Position;
-  Result := 1; // Byte block length
-  Data := Stream.ReadByte;
-  if Data = $ff then Result := GetVarSize + ReadVarUInt + 1
-  else begin
-    Result := DecodeUnaryLength(Data);
-  end;
-  Stream.Position := StoredPosition;
+  try
+    StoredPosition := Stream.Position;
+    Result := 1; // Byte block length
+    Data := Stream.ReadByte;
+
+    if Data = $ff then Result := GetVarSize + ReadVarUInt + 1
+    else begin
+      Result := DecodeUnaryLength(Data);
+    end;
+    Stream.Position := StoredPosition;
+  except
+    raise Exception.Create(SErrorGetVarSize);
+  end;
 end;
 
@@ -477 +483 @@
   I: Integer;
   StreamHelper: TStreamHelper;
+  RequestedSize: Integer;
 begin
   try
@@ -492 +499 @@
         StreamHelper.ReadStream(Data.Stream, GetVarSize);
     except
-      raise Exception.Create(SMaskedValueReadError);
+      //raise Exception.Create(SMaskedValueReadError);
+      // Error recovery for not enough source data in stream
+      Data.Stream.Size := 0;
+      Data.Stream.WriteByte(0);
     end;
   finally