-- fix overflow error in seekToChunk()

Summary:
- I love finding overflow errors.

Reviewed By: jwang

Test Plan: tested by rolling back search logfile

Notes:
- This should not affect anything currently in production.


git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@665020 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/lib/cpp/src/transport/TFileTransport.cpp b/lib/cpp/src/transport/TFileTransport.cpp
index 3f625bc..a9f3e9e 100644
--- a/lib/cpp/src/transport/TFileTransport.cpp
+++ b/lib/cpp/src/transport/TFileTransport.cpp
@@ -630,7 +630,8 @@
     minEndOffset = lseek(fd_, 0, SEEK_END);
   }
   
-  offset_ = lseek(fd_, chunk * chunkSize_, SEEK_SET);  
+  off_t newOffset = off_t(chunk) * chunkSize_;
+  offset_ = lseek(fd_, newOffset, SEEK_SET);  
   readState_.resetAllValues();
   if (offset_ == -1) {
     perror("TFileTransport: lseek error in seekToChunk");