sprint/io/mem.h

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/******************************************************************************
*   sprint::mem
*
*   Copyright (C) 2005-2011  Paolo Medici <www.pmx.it>
*
*  This library is free software; you can redistribute it and/or
*  modify it under the terms of the GNU Lesser General Public
*  License as published by the Free Software Foundation; either
*  version 2.1 of the License, or (at your option) any later version.
*
*  This library 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
*  Lesser General Public License for more details.
*
*  You should have received a copy of the GNU Lesser General Public
*  License along with this library; if not, write to the Free Software
*  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
*
*******************************************************************************/

#ifndef _SPRINT_IO_MEM_H
#define _SPRINT_IO_MEM_H

#include <sprint/io/type.h>
#include <algorithm>
#include <cstring>

namespace sprint {

namespace io {
  
template<bool buffer_mode>
class mem {
        char *m_data;
        int m_size;
        int m_cur_pos;
        
        public:
                mem() : m_data(0), m_size(0), m_cur_pos(0) { resize(4096); }
                mem(const char * src, int size) : m_data(0), m_size(0), m_cur_pos(0)
                { 
                  if(buffer_mode)
                  {
                    m_data = src;
                    m_size = size;
                  }
                  else
                  {
                    resize(size);
                    memcpy(m_data, src, size);
                  }
                }
                
                ~mem() { 
                  if(!buffer_mode) 
                        delete [] m_data; 
                  }

                void resize(int size)
                {
                  if(!buffer_mode)
                  {
                    if(size > m_size)
                    {
                      int suggested_size = (size + 65535) & 0xFFFF0000;
                      char *new_buf = new char [suggested_size];
                      
                      memcpy(new_buf, m_data, m_size);
                      m_size = suggested_size;
                      delete [] m_data;
                      m_data = new_buf;
                    }
                  }
                }

                int write(const char *buf, unsigned int size) {
                  if(!buffer_mode)
                  {
                  resize(m_cur_pos + size);
                  memcpy(m_data + m_cur_pos, buf, size);
                  m_cur_pos += size;
                  return size;
                  }
                  else
                  {
                    return -1;
                  }
                }
                
                int read(char *buf, unsigned int size) {
                  int remaing = std::min<int>(size, m_size - m_cur_pos);
                  memcpy(buf, m_data + m_cur_pos, remaing);
                  m_cur_pos += remaing;
                  return remaing;
                }
                
                int seek(int offset, int type) 
                { 
                        return sprint::io::unimplemented;
                }
                
                int length() const { return m_size; }
                
                state_t state() const { return sprint::io::unimplemented; }

                char * data() { return m_data; }
                const char * data() const { return m_data; }
        };

        typedef mem<true> dynamic_buffer;
        
        typedef mem<false> const_buffer;
        
} // io
        
} // sprint


#endif