sdsl/include/sdsl/vlc_vector.hpp

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/* sdsl - succinct data structures library
    Copyright (C) 2008 Simon Gog

    This program 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 of the License, or
    (at your option) any later version.

    This program 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 this program.  If not, see http://www.gnu.org/licenses/ .
*/
#include "int_vector.hpp"
#include "elias_delta_coder.hpp"
#include "iterators.hpp"

#ifndef SDSL_VLC_VECTOR
#define SDSL_VLC_VECTOR

namespace sdsl
{

template<uint8_t fixedIntWidth>
struct vlc_vector_trait {
    typedef int_vector<0> int_vector_type;
};

template<>
struct vlc_vector_trait<32> {
    typedef int_vector<32> int_vector_type;
};


template<class Coder=coder::elias_delta,
         uint32_t SampleDens = 16, uint8_t fixedIntWidth=0>
class vlc_vector
{
    public:
        typedef uint64_t                                                        value_type;     // STL Container requirement
        typedef random_access_const_iterator<vlc_vector> iterator;// STL Container requirement
        typedef iterator                                                        const_iterator; // STL Container requirement
        typedef const value_type                                        reference;
        typedef const value_type                                        const_reference;
        typedef const value_type*                                       const_pointer;
        typedef ptrdiff_t                                                       difference_type;// STL Container requirement
        typedef int_vector<>::size_type                         size_type;              // STL Container requirement
        typedef Coder                                                           coder;
        typedef typename vlc_vector_trait<fixedIntWidth>::int_vector_type int_vector_type;
        static  const uint32_t                                          sample_dens     = SampleDens;

        int_vector<0>   m_z;            // compressed bit stream
    private:
        int_vector_type   m_sample_pointer;
        size_type               m_elements;    // number of elements
        uint32_t                m_sample_dens;

        // workaround function for the constructor
        void construct() {
            m_elements = 0;
            m_sample_dens = 16;
        }
        void copy(const vlc_vector& v);

        void clear() {
            m_z.resize(0);
            m_elements = 0;
            m_sample_pointer.resize(0);
        }

    public:
        vlc_vector() {
            construct();
        };

        vlc_vector(const vlc_vector& v);


        template<class Container>
        vlc_vector(const Container& c) {
            construct();
            init(c);
        };

        /*
            \param v_buf A int_vector_file_buf.
                \pre No two adjacent values should be equal.
        */
        template<uint8_t int_width, class size_type_class>
        vlc_vector(int_vector_file_buffer<int_width, size_type_class>& v_buf) {
            construct();
            init(v_buf);
        }

        template<class Container>
        void init(const Container& c);

        template<uint8_t int_width, class size_type_class>
        void init(int_vector_file_buffer<int_width, size_type_class>& v_buf);

        ~vlc_vector() {
        };


        size_type size()const;


        static size_type max_size();


        bool empty() const;


        void swap(vlc_vector& v);


        const const_iterator begin()const;


        const const_iterator end()const;

        // Iterator that points to the last element of the vlc_vector.
        /*
         *      Required for the Container Concept of the STL.
         *  \sa rend()
         */
//              reverse_iterator rbegin()const;

        // Iterator that points to the position before the first element of the vlc_vector.
        /*
         *      Required for the Container Concept of the STL
         *  \sa rbegin()
         */
//              reverse_iterator rend()const;


        value_type operator[](size_type i)const;


        vlc_vector& operator=(const vlc_vector& v);


        bool operator==(const vlc_vector& v)const;


        bool operator!=(const vlc_vector& v)const;


        size_type serialize(std::ostream& out) const;

        void load(std::istream& in);


        value_type sample(const size_type i) const;

        uint32_t get_sample_dens() const;
        void set_sample_dens(const uint32_t sample_dens);
};


template<class Coder, uint32_t SampleDens, uint8_t fixedIntWidth>
inline uint32_t vlc_vector<Coder, SampleDens, fixedIntWidth>::get_sample_dens() const
{
    if (SampleDens == 0)
        return m_sample_dens;
    else
        return SampleDens;
}

template<class Coder, uint32_t SampleDens, uint8_t fixedIntWidth>
inline void vlc_vector<Coder, SampleDens, fixedIntWidth>::set_sample_dens(const uint32_t sample_dens)
{
    m_sample_dens = sample_dens;
}

template<class Coder, uint32_t SampleDens, uint8_t fixedIntWidth>
inline typename vlc_vector<Coder, SampleDens,fixedIntWidth>::value_type vlc_vector<Coder, SampleDens,fixedIntWidth>::operator[](const size_type i)const
{
    assert(i+1 != 0);
#ifdef SDSL_DEBUG
    if (i >= m_elements) {
        throw std::out_of_range("OUT_OF_RANGE_ERROR: vlc_vector::operator[](size_type); i >= size()!");
        return 0;
    }
#endif
    size_type idx = i/get_sample_dens();
    return (Coder::template decode<false, false, int*>(m_z.data(), m_sample_pointer[idx], i-SampleDens*idx+1)) - 1;
}

template<class Coder, uint32_t SampleDens, uint8_t fixedIntWidth>
inline vlc_vector<>::size_type vlc_vector<Coder, SampleDens,fixedIntWidth>::size()const
{
    return m_elements;
}

template<class Coder, uint32_t SampleDens, uint8_t fixedIntWidth>
inline vlc_vector<>::size_type vlc_vector<Coder, SampleDens,fixedIntWidth>::max_size()
{
    return int_vector<>::max_size()/2; // each element could possible occupy double space with selfdelimiting codes
}

template<class Coder, uint32_t SampleDens, uint8_t fixedIntWidth>
inline bool vlc_vector<Coder, SampleDens,fixedIntWidth>::empty()const
{
    return 0==m_elements;
}


template<class Coder, uint32_t SampleDens, uint8_t fixedIntWidth>
void vlc_vector<Coder, SampleDens,fixedIntWidth>::copy(const vlc_vector<Coder, SampleDens,fixedIntWidth>& v)
{
    m_z                                 = v.m_z;                                // copy compressed bit stream
    m_sample_pointer            = v.m_sample_pointer;      // copy sample values
    m_elements                  = v.m_elements;                 // copy number of stored elements
}

template<class Coder, uint32_t SampleDens, uint8_t fixedIntWidth>
vlc_vector<Coder, SampleDens,fixedIntWidth>::vlc_vector(const vlc_vector& v)
{
    copy(v);
}

template<class Coder, uint32_t SampleDens, uint8_t fixedIntWidth>
vlc_vector<Coder, SampleDens,fixedIntWidth>& vlc_vector<Coder, SampleDens,fixedIntWidth>::operator=(const vlc_vector<Coder, SampleDens,fixedIntWidth>& v)
{
    if (this != &v) {// if v and _this_ are not the same object
        copy(v);
    }
    return *this;
}

template<class Coder, uint32_t SampleDens, uint8_t fixedIntWidth>
bool vlc_vector<Coder, SampleDens,fixedIntWidth>::operator==(const vlc_vector<Coder, SampleDens,fixedIntWidth>& v)const
{
    if (this == &v)
        return true;
    return              m_elements == v.m_elements
                and     m_z == v.m_z
                and     m_sample_pointer == v.m_sample_pointer;
}

template<class Coder, uint32_t SampleDens, uint8_t fixedIntWidth>
bool vlc_vector<Coder, SampleDens,fixedIntWidth>::operator!=(const vlc_vector<Coder, SampleDens,fixedIntWidth>& v)const
{
    return !(*this == v);
}

template<class Coder, uint32_t SampleDens, uint8_t fixedIntWidth>
void vlc_vector<Coder, SampleDens,fixedIntWidth>::swap(vlc_vector<Coder, SampleDens,fixedIntWidth>& v)
{
    if (this != &v) { // if v and _this_ are not the same object
        m_z.swap(v.m_z);                                        // swap compressed bit streams
        m_sample_pointer.swap(v.m_sample_pointer);
        std::swap(m_elements, v.m_elements);// swap the number of elements
    }
}


template<class Coder, uint32_t SampleDens, uint8_t fixedIntWidth>
template<class Container>
void vlc_vector<Coder, SampleDens,fixedIntWidth>::init(const Container& c)
{
    // clear bit_vectors
    clear();

    if (c.empty())  // if c is empty there is nothing to do...
        return;
    size_type samples = 0, z_size = 0;
//  (1) Calculate size of z
    for (size_type i=0; i < c.size(); ++i) {
        if (c[i]+1<1) {
            throw std::logic_error("vlc_vector cannot decode values smaller than 1!");
        }
        z_size += Coder::encoding_length(c[i]+1);
    }
    samples = (c.size()+get_sample_dens()-1)/get_sample_dens();
//      (2) Write z

    m_sample_pointer.set_int_width(bit_magic::l1BP(z_size+1) + 1);
    m_sample_pointer.resize(samples+1); // add 1 for last entry

    std::cout<<"z_size="<<z_size<<std::endl;
    std::cout<<"int_width = "<<bit_magic::l1BP(z_size+1)+1<<std::endl;
    std::cout<<samples<<std::endl;

    m_z.bit_resize(z_size);
    z_size = 0;
    uint64_t* z_data = Coder::raw_data(m_z);
    uint8_t offset = 0;
    size_type no_sample = 0;
    for (size_type i=0, sample_cnt=0; i < c.size(); ++i, --no_sample) {
        if (!no_sample) { // add a sample pointer
            no_sample = get_sample_dens();
            m_sample_pointer[sample_cnt++] = z_size;
        }
        Coder::encode(c[i]+1, z_data, offset);
        z_size += Coder::encoding_length(c[i]+1);
    }
    m_elements = c.size();
}

template<class Coder, uint32_t SampleDens, uint8_t fixedIntWidth>
template<uint8_t int_width, class size_type_class>
void vlc_vector<Coder, SampleDens,fixedIntWidth>::init(int_vector_file_buffer<int_width, size_type_class>& v_buf)
{
    // clear bit_vectors
    clear();
    size_type n = v_buf.int_vector_size;
    if (n == 0)  // if c is empty there is nothing to do...
        return;
    v_buf.reset();
    size_type samples=0, z_size=0;
//  (1) Calculate size of z
    for (size_type i=0, r_sum=0, r = v_buf.load_next_block(); r_sum < n;) {
        for (; i < r_sum+r; ++i) {
            size_type x = v_buf[i-r_sum]+1;
            if (x < 1) {
                throw std::logic_error("vlc_vector cannot decode values smaller than 1!");
            }
            z_size += Coder::encoding_length(x);
        }
        r_sum += r; r = v_buf.load_next_block();
    }
    samples = (n+get_sample_dens()-1)/get_sample_dens();
//      (2) Write z

    m_sample_pointer.set_int_width(bit_magic::l1BP(z_size+1) + 1);
    m_sample_pointer.resize(samples+1); // add 1 for last entry

//     (b) Initilize bit_vector for encoded data
    m_z.bit_resize(z_size);
    z_size = 0;
    uint64_t* z_data = Coder::raw_data(m_z);
    uint8_t offset = 0;

//     (c) Write sample values and deltas
    v_buf.reset();
    size_type no_sample = 0;
    for (size_type i=0, sample_cnt = 0, r_sum=0, r = v_buf.load_next_block(); r_sum < n;) {
        for (; i < r_sum+r; ++i, --no_sample) {
            if (!no_sample) { // add a sample pointer
                no_sample = get_sample_dens();
                m_sample_pointer[sample_cnt++] = z_size;
            }
            size_type x = v_buf[i-r_sum]+1;
            Coder::encode(x, z_data, offset);   // write encoded values
            z_size += Coder::encoding_length(x);
        }
        r_sum += r; r = v_buf.load_next_block();
    }
    m_elements = n;
}


template<class Coder, uint32_t SampleDens, uint8_t fixedIntWidth>
vlc_vector<>::size_type vlc_vector<Coder, SampleDens,fixedIntWidth>::serialize(std::ostream& out) const
{
    size_type written_bytes = 0;
    out.write((char*) &m_elements, sizeof(m_elements));
    written_bytes += sizeof(m_elements);
    written_bytes += m_z.serialize(out);
    written_bytes += m_sample_pointer.serialize(out);
    return written_bytes;
}

template<class Coder, uint32_t SampleDens, uint8_t fixedIntWidth>
void vlc_vector<Coder, SampleDens,fixedIntWidth>::load(std::istream& in)
{
    in.read((char*) &m_elements, sizeof(m_elements));
    m_z.load(in);
    m_sample_pointer.load(in);
}

template<class Coder, uint32_t SampleDens, uint8_t fixedIntWidth>
const typename vlc_vector<Coder,SampleDens,fixedIntWidth>::const_iterator vlc_vector<Coder, SampleDens,fixedIntWidth>::begin()const
{
    return const_iterator(this, 0);
}

template<class Coder, uint32_t SampleDens, uint8_t fixedIntWidth>
const typename vlc_vector<Coder,SampleDens,fixedIntWidth>::const_iterator vlc_vector<Coder, SampleDens,fixedIntWidth>::end()const
{
    return const_iterator(this, this->m_elements);
}


} // end namespace sdsl

#endif