StringFileFeatures.cpp

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#include <shogun/features/StringFileFeatures.h>

namespace shogun
{

template <class ST> CStringFileFeatures<ST>::CStringFileFeatures() : CStringFeatures<ST>(), file(NULL)
{
}

template <class ST> CStringFileFeatures<ST>::CStringFileFeatures(const char* fname, EAlphabet alpha)
: CStringFeatures<ST>(alpha)
{
    file = new CMemoryMappedFile<ST>(fname);
    fetch_meta_info_from_file();
}

template <class ST> CStringFileFeatures<ST>::~CStringFileFeatures()
{
    SG_UNREF(file);
    CStringFileFeatures<ST>::cleanup();
}

template <class ST> ST* CStringFileFeatures<ST>::get_line(uint64_t& len, uint64_t& offs, int32_t& line_nr, uint64_t file_length)
{
    ST* s = file->get_map();
    for (uint64_t i=offs; i<file_length; i++)
    {
        ST c=s[i];

        if (c == '\n')
        {
            ST* line=&s[offs];
            len=i-offs;
            offs=i+1;
            line_nr++;
            return line;
        }
        else
        {
            if (!CStringFeatures<ST>::alphabet->is_valid((uint8_t) c))
            {
                CStringFileFeatures<ST>::cleanup();
                CStringFeatures<ST>::SG_ERROR("Invalid character (%c) in line %d\n", c, line_nr);
            }
        }
    }

    len=0;
    offs=file_length;
    return NULL;
}

template <class ST> void CStringFileFeatures<ST>::cleanup()
{
    CStringFeatures<ST>::num_vectors=0;
    SG_FREE(CStringFeatures<ST>::features);
    SG_FREE(CStringFeatures<ST>::symbol_mask_table);
    CStringFeatures<ST>::features=NULL;
    CStringFeatures<ST>::symbol_mask_table=NULL;

    /* start with a fresh alphabet, but instead of emptying the histogram
     * create a new object (to leave the alphabet object alone if it is used
     * by others)
     */
    CAlphabet* alpha=new CAlphabet(CStringFeatures<ST>::alphabet->get_alphabet());
    SG_UNREF(CStringFeatures<ST>::alphabet);
    CStringFeatures<ST>::alphabet=alpha;
    SG_REF(CStringFeatures<ST>::alphabet);
}

template <class ST> void CStringFileFeatures<ST>::cleanup_feature_vector(int32_t num)
{
    CStringFeatures<ST>::SG_ERROR("Cleaning single feature vector not"
            "supported by StringFileFeatures\n");
}

template <class ST> void CStringFileFeatures<ST>::fetch_meta_info_from_file(int32_t granularity)
{
    CStringFileFeatures<ST>::cleanup();
    uint64_t file_size=file->get_size();
    ASSERT(granularity>=1);
    ASSERT(CStringFeatures<ST>::alphabet);

    int64_t buffer_size=granularity;
    CStringFeatures<ST>::features=SG_MALLOC(SGString<ST>, buffer_size);

    uint64_t offs=0;
    uint64_t len=0;
    CStringFeatures<ST>::max_string_length=0;
    CStringFeatures<ST>::num_vectors=0;

    while (true)
    {
        ST* line=get_line(len, offs, CStringFeatures<ST>::num_vectors, file_size);

        if (line)
        {
            if (CStringFeatures<ST>::num_vectors > buffer_size)
            {
                CStringFeatures<ST>::features = SG_REALLOC(SGString<ST>, CStringFeatures<ST>::features, buffer_size+granularity);
                buffer_size+=granularity;
            }

            CStringFeatures<ST>::features[CStringFeatures<ST>::num_vectors-1].string=line;
            CStringFeatures<ST>::features[CStringFeatures<ST>::num_vectors-1].slen=len;
            CStringFeatures<ST>::max_string_length=CMath::max(CStringFeatures<ST>::max_string_length, (int32_t) len);
        }
        else
            break;
    }

    CStringFeatures<ST>::SG_INFO("number of strings:%d\n", CStringFeatures<ST>::num_vectors);
    CStringFeatures<ST>::SG_INFO("maximum string length:%d\n", CStringFeatures<ST>::max_string_length);
    CStringFeatures<ST>::SG_INFO("max_value_in_histogram:%d\n", CStringFeatures<ST>::alphabet->get_max_value_in_histogram());
    CStringFeatures<ST>::SG_INFO("num_symbols_in_histogram:%d\n", CStringFeatures<ST>::alphabet->get_num_symbols_in_histogram());

    if (!CStringFeatures<ST>::alphabet->check_alphabet_size() || !CStringFeatures<ST>::alphabet->check_alphabet())
        CStringFileFeatures<ST>::cleanup();

    CStringFeatures<ST>::features=SG_REALLOC(SGString<ST>, CStringFeatures<ST>::features, CStringFeatures<ST>::num_vectors);
}

template class CStringFileFeatures<bool>;
template class CStringFileFeatures<char>;
template class CStringFileFeatures<int8_t>;
template class CStringFileFeatures<uint8_t>;
template class CStringFileFeatures<int16_t>;
template class CStringFileFeatures<uint16_t>;
template class CStringFileFeatures<int32_t>;
template class CStringFileFeatures<uint32_t>;
template class CStringFileFeatures<int64_t>;
template class CStringFileFeatures<uint64_t>;
template class CStringFileFeatures<float32_t>;
template class CStringFileFeatures<float64_t>;
template class CStringFileFeatures<floatmax_t>;
}