1 files changed, 60 insertions, 0 deletions
diff --git a/gnuradio-runtime/lib/gr_circular_file.h b/gnuradio-runtime/lib/gr_circular_file.h
new file mode 100644
index 0000000000..2b61bf2711
--- /dev/null
+++ b/gnuradio-runtime/lib/gr_circular_file.h
@@ -0,0 +1,60 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2002 Free Software Foundation, Inc.
+ *
+ * This file is part of GNU Radio
+ *
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ *
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef _GR_CIRCULAR_FILE_H_
+#define _GR_CIRCULAR_FILE_H_
+
+#include <gr_runtime_api.h>
+
+/*
+ * writes input data into a circular buffer on disk.
+ *
+ * the file contains a fixed header:
+ *   0x0000:    int32 magic (0xEB021026)
+ *   0x0004:	int32 size in bytes of header (constant 4096)
+ *   0x0008:	int32 size in bytes of circular buffer (not including header)
+ *   0x000C:    int32 file offset to beginning of circular buffer
+ *   0x0010:    int32 byte offset from beginning of circular buffer to
+ *		      current start of data
+ *
+ */
+class GR_RUNTIME_API gr_circular_file {
+  int		 d_fd;
+  int		*d_header;
+  unsigned char	*d_buffer;
+  int		 d_mapped_size;
+  int		 d_bytes_read;
+
+public:
+  gr_circular_file (const char *filename, bool writable = false, int size = 0);
+  ~gr_circular_file ();
+
+  bool write (void *data, int nbytes);
+
+  // returns # of bytes actually read or 0 if end of buffer, or -1 on error.
+  int read (void *data, int nbytes);
+
+  // reset read pointer to beginning of buffer.
+  void reset_read_pointer ();
+};
+
+#endif /* _GR_CIRCULAR_FILE_H_ */
+\ No newline at end of file