1 files changed, 196 insertions, 0 deletions
diff --git a/gnuradio-core/src/lib/runtime/gr_buffer.h b/gnuradio-core/src/lib/runtime/gr_buffer.h
new file mode 100644
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+++ b/gnuradio-core/src/lib/runtime/gr_buffer.h
@@ -0,0 +1,196 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2004 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 2, 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., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifndef INCLUDED_GR_BUFFER_H
+#define INCLUDED_GR_BUFFER_H
+
+#include <gr_runtime.h>
+
+class gr_vmcircbuf;
+
+/*!
+ * \brief Allocate a buffer that holds at least \p nitems of size \p sizeof_item.
+ *
+ * The total size of the buffer will be rounded up to a system
+ * dependent boundary.  This is typically the system page size, but
+ * under MS windows is 64KB.
+ */
+gr_buffer_sptr gr_make_buffer (int nitems, size_t sizeof_item);
+
+
+/*!
+ * \brief Single writer, multiple reader fifo.
+ * \ingroup internal
+ */
+class gr_buffer {
+ public:
+  virtual ~gr_buffer ();
+
+  /*!
+   * \brief return number of items worth of space available for writing
+   */
+  int space_available () const;
+
+  /*!
+   * \brief return pointer to write buffer.
+   *
+   * The return value points at space that can hold at least
+   * space_available() items.
+   */
+  void *write_pointer ();
+
+  /*!
+   * \brief tell buffer that we wrote \p nitems into it
+   */
+  void update_write_pointer (int nitems);
+
+
+  void set_done (bool done)   { d_done = done; }
+  bool done () const { return d_done; }
+
+  // -------------------------------------------------------------------------
+
+ private:
+
+  friend class gr_buffer_reader;
+  friend gr_buffer_sptr gr_make_buffer (int nitems, size_t sizeof_item);
+  friend gr_buffer_reader_sptr gr_buffer_add_reader (gr_buffer_sptr buf, int history);
+
+ protected:
+  char				       *d_base;		// base address of buffer
+  unsigned int	 			d_bufsize;	// in items
+ private:
+  gr_vmcircbuf			       *d_vmcircbuf;
+  size_t	 			d_sizeof_item;	// in bytes
+  unsigned int				d_write_index;	// in items [0,d_bufsize)
+  std::vector<gr_buffer_reader *>	d_readers;
+  bool					d_done;
+  
+  unsigned
+  index_add (unsigned a, unsigned b)
+  {
+    unsigned s = a + b;
+
+    if (s >= d_bufsize)
+      s -= d_bufsize;
+
+    assert (s < d_bufsize);
+    return s;
+  }
+
+  unsigned
+  index_sub (unsigned a, unsigned b)
+  {
+    int s = a - b;
+
+    if (s < 0)
+      s += d_bufsize;
+
+    assert ((unsigned) s < d_bufsize);
+    return s;
+  }
+
+  virtual bool allocate_buffer (int nitems, size_t sizeof_item);
+
+  /*!
+   * \brief constructor is private.  Use gr_make_buffer to create instances.
+   *
+   * Allocate a buffer that holds at least \p nitems of size \p sizeof_item.
+   *
+   * The total size of the buffer will be rounded up to a system
+   * dependent boundary.  This is typically the system page size, but
+   * under MS windows is 64KB.
+   */
+  gr_buffer (int nitems, size_t sizeof_item);
+
+  /*!
+   * \brief disassociate \p reader from this buffer
+   */
+  void drop_reader (gr_buffer_reader *reader);
+
+};
+
+//! create a new gr_buffer_reader and attach it to buffer \p buf
+gr_buffer_reader_sptr gr_buffer_add_reader (gr_buffer_sptr buf, int history);
+
+//! returns # of gr_buffers currently allocated
+long gr_buffer_ncurrently_allocated ();
+
+
+// ---------------------------------------------------------------------------
+
+/*!
+ * \brief How we keep track of the readers of a gr_buffer.
+ * \ingroup internal
+ */
+
+class gr_buffer_reader {
+
+ public:
+  ~gr_buffer_reader ();
+
+  /*!
+   * \brief Return number of items available for reading.
+   */
+  int items_available () const;
+
+  /*!
+   * \brief Return maximum number of items that could ever be available for reading.
+   * This is used as a sanity check in the scheduler to avoid looping forever.
+   */
+  int max_possible_items_available () const { return d_buffer->d_bufsize - 1; }
+
+  /*!
+   * \brief return pointer to read buffer.
+   *
+   * The return value points to items_available() number of items
+   */
+  const void *read_pointer ();
+
+  /*
+   * \brief tell buffer we read \p items from it
+   */
+  void update_read_pointer (int nitems);
+
+  void set_done (bool done)   { d_buffer->set_done (done); }
+  bool done () const { return d_buffer->done (); }
+
+  // -------------------------------------------------------------------------
+
+ private:
+
+  friend class gr_buffer;
+  friend gr_buffer_reader_sptr gr_buffer_add_reader (gr_buffer_sptr buf, int history);
+
+
+  gr_buffer_sptr		d_buffer;
+  unsigned int			d_read_index;	// in items [0,d->buffer.d_bufsize)
+
+  //! constructor is private.  Use gr_buffer::add_reader to create instances
+  gr_buffer_reader (gr_buffer_sptr buffer, unsigned int read_index);
+};
+
+//! returns # of gr_buffer_readers currently allocated
+long gr_buffer_reader_ncurrently_allocated ();
+
+
+#endif /* INCLUDED_GR_BUFFER_H */