259 lines
7.8 KiB
C++
259 lines
7.8 KiB
C++
/* -*- c++ -*- */
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/*
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* Copyright 2004,2009-2011,2013 Free Software Foundation, Inc.
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*
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* This file is part of GNU Radio
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*
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* GNU Radio is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3, or (at your option)
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* any later version.
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*
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* GNU Radio is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GNU Radio; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street,
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* Boston, MA 02110-1301, USA.
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*/
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#ifndef INCLUDED_GR_RUNTIME_BUFFER_H
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#define INCLUDED_GR_RUNTIME_BUFFER_H
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#include <gnuradio/api.h>
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#include <gnuradio/runtime_types.h>
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#include <boost/weak_ptr.hpp>
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#include <gnuradio/thread/thread.h>
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#include <deque>
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namespace gr {
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class vmcircbuf;
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/*!
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* \brief Allocate a buffer that holds at least \p nitems of size \p sizeof_item.
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*
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* The total size of the buffer will be rounded up to a system
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* dependent boundary. This is typically the system page size, but
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* under MS windows is 64KB.
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*
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* \param nitems is the minimum number of items the buffer will hold.
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* \param sizeof_item is the size of an item in bytes.
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* \param link is the block that writes to this buffer.
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*/
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GR_RUNTIME_API buffer_sptr make_buffer(int nitems, size_t sizeof_item,
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block_sptr link=block_sptr());
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/*!
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* \brief Single writer, multiple reader fifo.
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* \ingroup internal
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*/
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class GR_RUNTIME_API buffer
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{
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public:
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virtual ~buffer();
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/*!
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* \brief return number of items worth of space available for writing
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*/
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int space_available();
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/*!
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* \brief return size of this buffer in items
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*/
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int bufsize() const { return d_bufsize; }
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/*!
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* \brief return pointer to write buffer.
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*
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* The return value points at space that can hold at least
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* space_available() items.
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*/
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void *write_pointer();
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/*!
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* \brief tell buffer that we wrote \p nitems into it
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*/
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void update_write_pointer(int nitems);
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void set_done(bool done);
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bool done() const { return d_done; }
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/*!
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* \brief Return the block that writes to this buffer.
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*/
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block_sptr link() { return block_sptr(d_link); }
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size_t nreaders() const { return d_readers.size(); }
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buffer_reader* reader(size_t index) { return d_readers[index]; }
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gr::thread::mutex *mutex() { return &d_mutex; }
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uint64_t nitems_written() { return d_abs_write_offset; }
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size_t get_sizeof_item() { return d_sizeof_item; }
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// -------------------------------------------------------------------------
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private:
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friend class buffer_reader;
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friend GR_RUNTIME_API buffer_sptr make_buffer(int nitems, size_t sizeof_item, block_sptr link);
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friend GR_RUNTIME_API buffer_reader_sptr buffer_add_reader(buffer_sptr buf, int nzero_preload, block_sptr link);
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protected:
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char *d_base; // base address of buffer
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unsigned int d_bufsize; // in items
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private:
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gr::vmcircbuf *d_vmcircbuf;
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size_t d_sizeof_item; // in bytes
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std::vector<buffer_reader *> d_readers;
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boost::weak_ptr<block> d_link; // block that writes to this buffer
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//
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// The mutex protects d_write_index, d_abs_write_offset, d_done, d_item_tags
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// and the d_read_index's and d_abs_read_offset's in the buffer readers.
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//
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gr::thread::mutex d_mutex;
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unsigned int d_write_index; // in items [0,d_bufsize)
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uint64_t d_abs_write_offset; // num items written since the start
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bool d_done;
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uint64_t d_last_min_items_read;
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unsigned index_add(unsigned a, unsigned b)
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{
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unsigned s = a + b;
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if(s >= d_bufsize)
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s -= d_bufsize;
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assert(s < d_bufsize);
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return s;
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}
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unsigned index_sub(unsigned a, unsigned b)
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{
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int s = a - b;
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if(s < 0)
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s += d_bufsize;
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assert((unsigned) s < d_bufsize);
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return s;
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}
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virtual bool allocate_buffer(int nitems, size_t sizeof_item);
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/*!
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* \brief constructor is private. Use gr_make_buffer to create instances.
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*
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* Allocate a buffer that holds at least \p nitems of size \p sizeof_item.
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*
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* \param nitems is the minimum number of items the buffer will hold.
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* \param sizeof_item is the size of an item in bytes.
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* \param link is the block that writes to this buffer.
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*
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* The total size of the buffer will be rounded up to a system
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* dependent boundary. This is typically the system page size, but
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* under MS windows is 64KB.
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*/
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buffer(int nitems, size_t sizeof_item, block_sptr link);
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/*!
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* \brief disassociate \p reader from this buffer
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*/
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void drop_reader(buffer_reader *reader);
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};
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/*!
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* \brief Create a new gr::buffer_reader and attach it to buffer \p buf
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* \param buf is the buffer the \p gr::buffer_reader reads from.
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* \param nzero_preload -- number of zero items to "preload" into buffer.
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* \param link is the block that reads from the buffer using this gr::buffer_reader.
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*/
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GR_RUNTIME_API buffer_reader_sptr
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buffer_add_reader(buffer_sptr buf, int nzero_preload, block_sptr link=block_sptr());
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//! returns # of buffers currently allocated
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GR_RUNTIME_API long buffer_ncurrently_allocated();
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// ---------------------------------------------------------------------------
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/*!
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* \brief How we keep track of the readers of a gr::buffer.
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* \ingroup internal
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*/
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class GR_RUNTIME_API buffer_reader
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{
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public:
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~buffer_reader();
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/*!
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* \brief Return number of items available for reading.
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*/
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int items_available() const;
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/*!
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* \brief Return buffer this reader reads from.
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*/
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buffer_sptr buffer() const { return d_buffer; }
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/*!
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* \brief Return maximum number of items that could ever be available for reading.
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* This is used as a sanity check in the scheduler to avoid looping forever.
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*/
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int max_possible_items_available() const { return d_buffer->d_bufsize - 1; }
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/*!
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* \brief return pointer to read buffer.
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*
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* The return value points to items_available() number of items
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*/
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const void *read_pointer();
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/*
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* \brief tell buffer we read \p items from it
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*/
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void update_read_pointer(int nitems);
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void set_done(bool done) { d_buffer->set_done(done); }
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bool done() const { return d_buffer->done(); }
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gr::thread::mutex *mutex() { return d_buffer->mutex(); }
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uint64_t nitems_read() { return d_abs_read_offset; }
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size_t get_sizeof_item() { return d_buffer->get_sizeof_item(); }
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/*!
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* \brief Return the block that reads via this reader.
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*
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*/
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block_sptr link() { return block_sptr(d_link); }
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// -------------------------------------------------------------------------
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private:
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friend class buffer;
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friend GR_RUNTIME_API buffer_reader_sptr
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buffer_add_reader(buffer_sptr buf, int nzero_preload, block_sptr link);
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buffer_sptr d_buffer;
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unsigned int d_read_index; // in items [0,d->buffer.d_bufsize)
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uint64_t d_abs_read_offset; // num items seen since the start
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boost::weak_ptr<block> d_link; // block that reads via this buffer reader
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//! constructor is private. Use gr::buffer::add_reader to create instances
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buffer_reader(buffer_sptr buffer, unsigned int read_index, block_sptr link);
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};
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//! returns # of buffer_readers currently allocated
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GR_RUNTIME_API long buffer_reader_ncurrently_allocated ();
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} /* namespace gr */
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#endif /* INCLUDED_GR_RUNTIME_BUFFER_H */
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