1 files changed, 65 insertions, 0 deletions
diff --git a/gnuradio-runtime/lib/circular_file.h b/gnuradio-runtime/lib/circular_file.h
new file mode 100644
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+++ b/gnuradio-runtime/lib/circular_file.h
@@ -0,0 +1,65 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2002,2013 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 <gnuradio/api.h>
+
+namespace gr {
+
+  /*
+   * 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 circular_file
+  {
+  private:
+    int  d_fd;
+    int	*d_header;
+    unsigned char *d_buffer;
+    int d_mapped_size;
+    int d_bytes_read;
+
+  public:
+    circular_file(const char *filename, bool writable = false, int size = 0);
+    ~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();
+  };
+
+} /* namespace gr */
+
+#endif /* GR_CIRCULAR_FILE_H */