BufferUnSync.hpp

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/***************************************************************************
  tag: Peter Soetens  Thu Oct 22 11:59:07 CEST 2009  BufferUnSync.hpp

                        BufferUnSync.hpp -  description
                           -------------------
    begin                : Thu October 22 2009
    copyright            : (C) 2009 Peter Soetens
    email                : peter@thesourcworks.com

 ***************************************************************************
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#ifndef ORO_CORELIB_BUFFER_UNSYNC_HPP
#define ORO_CORELIB_BUFFER_UNSYNC_HPP

#include "BufferInterface.hpp"
#include <deque>

namespace RTT
{ namespace base {


    template<class T>
    class BufferUnSync
        :public BufferInterface<T>
    {
    public:
        typedef typename BufferInterface<T>::reference_t reference_t;
        typedef typename BufferInterface<T>::param_t param_t;
        typedef typename BufferInterface<T>::size_type size_type;
        typedef T value_t;

        BufferUnSync( size_type size, const T& initial_value = T(), bool circular = false )
            : cap(size), buf(), mcircular(circular), droppedSamples(0)
        {
            data_sample(initial_value);
        }

        virtual void data_sample( const T& sample )
        {
            buf.resize(cap, sample);
            buf.resize(0);
        }

        virtual T data_sample() const
        {
            return lastSample;
        }

        ~BufferUnSync() {}

        bool Push( param_t item )
        {
            if (cap == (size_type)buf.size() ) {
                //buffer is full, we either overwrite a sample, or drop the given one
                droppedSamples++;
                if (!mcircular)
                {
                    return false;
                }
                else
                {
                    buf.pop_front();
                }
            }
            buf.push_back( item );
            return true;
        }

        size_type Push(const std::vector<T>& items)
        {
            typename std::vector<T>::const_iterator itl( items.begin() );
            if (mcircular && (size_type)items.size() >= cap ) {
                // clear out current data and reset iterator to first element we're going to take.
                buf.clear();
                //note the ignored samples are added below to the dropped samples.
                droppedSamples += cap;
                itl = items.begin() + ( items.size() - cap );
            } else if ( mcircular && (size_type)(buf.size() + items.size()) > cap) {
                // drop excess elements from front
                assert( (size_type)items.size() < cap );
                while ( (size_type)(buf.size() + items.size()) > cap )
                {
                    droppedSamples++;
                    buf.pop_front();
                }
                // itl still points at first element of items.
            }
            while ( ((size_type)buf.size() != cap) && (itl != items.end()) ) {
                buf.push_back( *itl );
                ++itl;
            }
            
            size_type written = (itl - items.begin());
            
            droppedSamples += items.size() - written;
            
            return written;
        }

        bool Pop( reference_t item )
        {
            if ( buf.empty() ) {
                return false;
            }
            item = buf.front();
            buf.pop_front();
            return true;
        }

        size_type Pop(std::vector<T>& items )
        {
            int quant = 0;
            items.clear();
            while ( !buf.empty() ) {
                items.push_back( buf.front() );
                buf.pop_front();
                ++quant;
            }
            return quant;
        }

    value_t* PopWithoutRelease()
    {
        if(buf.empty())
        return 0;
        
        //note we need to copy the sample, as 
        //front is not garanteed to be valid after
        //any other operation on the deque
        lastSample = buf.front();
        buf.pop_front();
        return &lastSample;

        return 0;
    }
    
    void Release(value_t *item)
    {
        //we do not need to release any memory, but we can check
        //if the other side messed up
        assert(item == &lastSample && "Wrong pointer given back to buffer");
    }
    
        size_type capacity() const {
            return cap;
        }

        size_type size() const {
            return buf.size();
        }

        void clear() {
            buf.clear();
        }

        bool empty() const {
            return buf.empty();
        }

        bool full() const {
            return (size_type)buf.size() ==  cap;
        }
        
        virtual size_type dropped() const
        {
            return droppedSamples;
        }
    private:
        size_type cap;
        std::deque<T> buf;
        value_t lastSample;
        const bool mcircular;
        size_type droppedSamples;
    };
}}

#endif // BUFFERSIMPLE_HPP