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#ifndef PCL_IO_BUFFERS_H
#define PCL_IO_BUFFERS_H
#include <vector>
#include <limits>
#include <cassert>
#include <boost/cstdint.hpp>
#include <boost/thread/mutex.hpp>
namespace pcl
{
namespace io
{
/** An abstract base class for fixed-size data buffers.
*
* A new chunk of data can be inserted using the push() method; the data
* elements stored in the buffer can be accessed using operator[]().
*
* Concrete implementations of this interface (such as AverageBuffer or
* MedianBuffer) may perform arbitrary data processing under the hood and
* provide access to certain quantities computed based on the input data
* rather than the data themselves.
*
* \author Sergey Alexandrov
* \ingroup io */
template <typename T>
class Buffer
{
public:
typedef T value_type;
virtual
~Buffer ();
/** Access an element at a given index. */
virtual T
operator[] (size_t idx) const = 0;
/** Insert a new chunk of data into the buffer.
*
* Note that the \a data parameter is not `const`-qualified. This is
* done to allow deriving classes to implement no-copy data insertion,
* where the data is "stolen" from the input argument. */
virtual void
push (std::vector<T>& data) = 0;
/** Get the size of the buffer. */
inline size_t
size () const
{
return (size_);
}
protected:
Buffer (size_t size);
const size_t size_;
};
/** A simple buffer that only stores data.
*
* The buffer is thread-safe. */
template <typename T>
class SingleBuffer : public Buffer<T>
{
public:
/** Construct a buffer of given size. */
SingleBuffer (size_t size);
virtual
~SingleBuffer ();
virtual T
operator[] (size_t idx) const;
virtual void
push (std::vector<T>& data);
private:
std::vector<T> data_;
mutable boost::mutex data_mutex_;
using Buffer<T>::size_;
};
/** A buffer that computes running window median of the data inserted.
*
* The buffer and window sizes are specified at construction time. The
* buffer size defines the number of elements in each data chunk that is
* inserted in the buffer. The window size is the number of last data
* chunks that are considered for median computation. The median is
* computed separately for 1st, 2nd, etc. element in data chunks.
*
* The data can contain invalid elements. For integral types zeros are
* assumed to be invalid elements, whereas for floating-point types it is
* quiet NaN. Invalid elements are ignored when computing median.
*
* The buffer is thread-safe. */
template <typename T>
class MedianBuffer : public Buffer<T>
{
public:
/** Construct a buffer of given size with given running window size.
*
* \param[in] size buffer size
* \param[in] window_size running window size over which the median
* value should be computed (0..255) */
MedianBuffer (size_t size, unsigned char window_size);
virtual
~MedianBuffer ();
/** Access an element at a given index.
*
* This operation is constant time. */
virtual T
operator[] (size_t idx) const;
/** Insert a new chunk of data into the buffer.
*
* This operation is linear in buffer size and window size.
*
* \param[in] data input data chunk, the memory will be "stolen" */
virtual void
push (std::vector<T>& data);
private:
/** Compare two data elements.
*
* Invalid value is assumed to be larger than everything else. If both values
* are invalid, they are assumed to be equal.
*
* \return -1 if \c a < \c b, 0 if \c a == \c b, 1 if \c a > \c b */
static int compare (T a, T b);
const unsigned char window_size_;
const unsigned char midpoint_;
/// Data pushed into the buffer (last window_size_ chunks), logically
/// organized as a circular buffer
std::vector<std::vector<T> > data_;
/// Index of the last pushed data chunk in the data_ circular buffer
unsigned char data_current_idx_;
/// Indices that the argsort function would produce for data_ (with
/// dimensions swapped)
std::vector<std::vector<unsigned char> > data_argsort_indices_;
/// Number of invalid values in the buffer
std::vector<unsigned char> data_invalid_count_;
mutable boost::mutex data_mutex_;
using Buffer<T>::size_;
};
/** A buffer that computes running window average of the data inserted.
*
* The buffer and window sizes are specified at construction time. The
* buffer size defines the number of elements in each data chunk that is
* inserted in the buffer. The window size is the number of last data
* chunks that are considered for average computation. The average is
* computed separately for 1st, 2nd, etc. element in data chunks.
*
* The data can contain invalid elements. For integral types zeros are
* assumed to be invalid elements, whereas for floating-point types it is
* quiet NaN. Invalid elements are ignored when computing average.
*
* The buffer is thread-safe. */
template <typename T>
class AverageBuffer : public Buffer<T>
{
public:
/** Construct a buffer of given size with given running window size.
*
* \param[in] size buffer size
* \param[in] window_size running window size over which the median
* value should be computed (0..255) */
AverageBuffer (size_t size, unsigned char window_size);
virtual
~AverageBuffer ();
/** Access an element at a given index.
*
* This operation is constant time. */
virtual T
operator[] (size_t idx) const;
/** Insert a new chunk of data into the buffer.
*
* This operation is linear in buffer size.
*
* \param[in] data input data chunk, the memory will be "stolen" */
virtual void
push (std::vector<T>& data);
private:
const unsigned char window_size_;
/// Data pushed into the buffer (last window_size_ chunks), logically
/// organized as a circular buffer
std::vector<std::vector<T> > data_;
/// Index of the last pushed data chunk in the data_ circular buffer
unsigned char data_current_idx_;
/// Current sum of the buffer
std::vector<T> data_sum_;
/// Number of invalid values in the buffer
std::vector<unsigned char> data_invalid_count_;
mutable boost::mutex data_mutex_;
using Buffer<T>::size_;
};
}
}
#include <pcl/io/impl/buffers.hpp>
#endif /* PCL_IO_BUFFERS_H */