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

llvm-svn: 63044

llvm/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.

llvm/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
 //===----------------------------------------------------------------------===//