/* -*- c++ -*- */
/*
* Copyright 2004,2009-2011,2013 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 INCLUDED_GR_RUNTIME_BUFFER_H
#define INCLUDED_GR_RUNTIME_BUFFER_H
#include <gnuradio/api.h>
#include <gnuradio/runtime_types.h>
#include <gnuradio/tags.h>
#include <boost/weak_ptr.hpp>
#include <gnuradio/thread/thread.h>
#include <deque>
namespace gr {
class 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.
*
* \param nitems is the minimum number of items the buffer will hold.
* \param sizeof_item is the size of an item in bytes.
* \param link is the block that writes to this buffer.
*/
GR_RUNTIME_API buffer_sptr make_buffer(int nitems, size_t sizeof_item,
block_sptr link=block_sptr());
/*!
* \brief Single writer, multiple reader fifo.
* \ingroup internal
*/
class GR_RUNTIME_API buffer
{
public:
virtual ~buffer();
/*!
* \brief return number of items worth of space available for writing
*/
int space_available();
/*!
* \brief return size of this buffer in items
*/
int bufsize() const { return d_bufsize; }
/*!
* \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);
bool done() const { return d_done; }
/*!
* \brief Return the block that writes to this buffer.
*/
block_sptr link() { return block_sptr(d_link); }
size_t nreaders() const { return d_readers.size(); }
buffer_reader* reader(size_t index) { return d_readers[index]; }
gr::thread::mutex *mutex() { return &d_mutex; }
uint64_t nitems_written() { return d_abs_write_offset; }
size_t get_sizeof_item() { return d_sizeof_item; }
/*!
* \brief Adds a new tag to the buffer.
*
* \param tag the new tag
*/
void add_item_tag(const tag_t &tag);
/*!
* \brief Removes an existing tag from the buffer.
*
* If no such tag is found, does nothing.
*
* \param tag the tag that needs to be removed
*/
void remove_item_tag(const tag_t &tag);
/*!
* \brief Removes all tags before \p max_time from buffer
*
* \param max_time the time (item number) to trim up until.
*/
void prune_tags(uint64_t max_time);
std::deque<tag_t>::iterator get_tags_begin() { return d_item_tags.begin(); }
std::deque<tag_t>::iterator get_tags_end() { return d_item_tags.end(); }
// -------------------------------------------------------------------------
private:
friend class buffer_reader;
friend GR_RUNTIME_API buffer_sptr make_buffer(int nitems, size_t sizeof_item, block_sptr link);
friend GR_RUNTIME_API buffer_reader_sptr buffer_add_reader(buffer_sptr buf, int nzero_preload, block_sptr link);
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
std::vector<buffer_reader *> d_readers;
boost::weak_ptr<block> d_link; // block that writes to this buffer
//
// The mutex protects d_write_index, d_abs_write_offset, d_done, d_item_tags
// and the d_read_index's and d_abs_read_offset's in the buffer readers.
//
gr::thread::mutex d_mutex;
unsigned int d_write_index; // in items [0,d_bufsize)
uint64_t d_abs_write_offset; // num items written since the start
bool d_done;
std::deque<tag_t> d_item_tags;
uint64_t d_last_min_items_read;
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.
*
* \param nitems is the minimum number of items the buffer will hold.
* \param sizeof_item is the size of an item in bytes.
* \param link is the block that writes to this buffer.
*
* 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.
*/
buffer(int nitems, size_t sizeof_item, block_sptr link);
/*!
* \brief disassociate \p reader from this buffer
*/
void drop_reader(buffer_reader *reader);
};
/*!
* \brief Create a new gr::buffer_reader and attach it to buffer \p buf
* \param buf is the buffer the \p gr::buffer_reader reads from.
* \param nzero_preload -- number of zero items to "preload" into buffer.
* \param link is the block that reads from the buffer using this gr::buffer_reader.
*/
GR_RUNTIME_API buffer_reader_sptr
buffer_add_reader(buffer_sptr buf, int nzero_preload, block_sptr link=block_sptr());
//! returns # of buffers currently allocated
GR_RUNTIME_API long buffer_ncurrently_allocated();
// ---------------------------------------------------------------------------
/*!
* \brief How we keep track of the readers of a gr::buffer.
* \ingroup internal
*/
class GR_RUNTIME_API buffer_reader
{
public:
~buffer_reader();
/*!
* \brief Return number of items available for reading.
*/
int items_available() const;
/*!
* \brief Return buffer this reader reads from.
*/
buffer_sptr buffer() const { return d_buffer; }
/*!
* \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(); }
gr::thread::mutex *mutex() { return d_buffer->mutex(); }
uint64_t nitems_read() { return d_abs_read_offset; }
size_t get_sizeof_item() { return d_buffer->get_sizeof_item(); }
/*!
* \brief Return the block that reads via this reader.
*
*/
block_sptr link() { return block_sptr(d_link); }
/*!
* \brief Given a [start,end), returns a vector all tags in the range.
*
* Get a vector of tags in given range. Range of counts is from start to end-1.
*
* Tags are tuples of:
* (item count, source id, key, value)
*
* \param v a vector reference to return tags into
* \param abs_start a uint64 count of the start of the range of interest
* \param abs_end a uint64 count of the end of the range of interest
*/
void get_tags_in_range(std::vector<tag_t> &v,
uint64_t abs_start,
uint64_t abs_end);
// -------------------------------------------------------------------------
private:
friend class buffer;
friend GR_RUNTIME_API buffer_reader_sptr
buffer_add_reader(buffer_sptr buf, int nzero_preload, block_sptr link);
buffer_sptr d_buffer;
unsigned int d_read_index; // in items [0,d->buffer.d_bufsize)
uint64_t d_abs_read_offset; // num items seen since the start
boost::weak_ptr<block> d_link; // block that reads via this buffer reader
//! constructor is private. Use gr::buffer::add_reader to create instances
buffer_reader(buffer_sptr buffer, unsigned int read_index, block_sptr link);
};
//! returns # of buffer_readers currently allocated
GR_RUNTIME_API long buffer_reader_ncurrently_allocated ();
} /* namespace gr */
#endif /* INCLUDED_GR_RUNTIME_BUFFER_H */