CircularBuffer.h

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/*
 * 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.
 *
 * Written (W) 2013 Engeniy Andreev (gsomix)
 */

#ifndef __CIRCULARBUFFER_H_
#define __CIRCULARBUFFER_H_

#include <shogun/base/SGObject.h>
#include <shogun/lib/SGVector.h>
#include <shogun/lib/Tokenizer.h>

namespace shogun
{

class CCircularBuffer : public CSGObject
{
public:
    CCircularBuffer();

    CCircularBuffer(int32_t buffer_size);

    ~CCircularBuffer();

    void set_tokenizer(CTokenizer* tokenizer);

    int32_t push(SGVector<char> source);

    int32_t push(FILE* source, int32_t source_size);

    SGVector<char> pop(int32_t num_chars);

    bool has_next();

    index_t next_token_idx(index_t &start);

    void skip_characters(int32_t num_chars);

    int32_t available() const 
    {
        return m_bytes_available;
    }

    int32_t num_bytes_contained() const
    {
        return m_bytes_count;
    }

    void clear();

    virtual const char* get_name() const { return "CircularBuffer"; }

private:
    void init();

    int32_t append_chunk(const char* source, int32_t source_size, 
                    bool from_buffer_begin);
    
    int32_t append_chunk(FILE* source, int32_t source_size,
                    bool from_buffer_begin);

    void detach_chunk(char** dest, int32_t* dest_size, int32_t dest_offset, int32_t num_bytes, 
                    bool from_buffer_begin);

    bool has_next_locally(char* begin, char* end);

    index_t next_token_idx_locally(index_t &start, char* begin, char* end);

    void move_pointer(char** pointer, char* new_position);

private:
    SGVector<char> m_buffer;

    char* m_buffer_end;

    char* m_begin_pos;

    char* m_end_pos;

    CTokenizer* m_tokenizer;

    index_t m_last_idx;

    int32_t m_bytes_available;

    int32_t m_bytes_count;
};

}

#endif /* _CIRCULARBUFFER_H_ */