Add method raw_fd_ostream::seek() for random access within a file.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63044 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 11 insertions, 1 deletions

diff --git a/include/llvm/Support/raw_ostream.h b/include/llvm/Support/raw_ostream.h
index 1a4f6bf6f4..030412169d 100644
--- a/include/llvm/Support/raw_ostream.h
+++ b/include/llvm/Support/raw_ostream.h
@@ -181,7 +181,11 @@ public:
   /// tell - Return the current offset with the file.
   uint64_t tell() {
     return pos + (OutBufCur - OutBufStart);
-  }  
+  }
+  
+  /// seek - Flushes the stream and repositions the underlying file descriptor
+  ///  positition to the offset specified from the beginning of the file.
+  uint64_t seek(uint64_t off);
 };
   
 /// raw_stdout_ostream - This is a stream that always prints to stdout.
diff --git a/lib/Support/raw_ostream.cpp b/lib/Support/raw_ostream.cpp
index 96c9a3a263..29665dc350 100644
--- a/lib/Support/raw_ostream.cpp
+++ b/lib/Support/raw_ostream.cpp
@@ -255,6 +255,12 @@ void raw_fd_ostream::close() {
   FD = -1;
 }
 
+uint64_t raw_fd_ostream::seek(uint64_t off) {
+  flush();
+  pos = lseek(FD, off, SEEK_SET);
+  return pos;  
+}
+
 //===----------------------------------------------------------------------===//
 //  raw_stdout/err_ostream
 //===----------------------------------------------------------------------===//