#ifndef _COMMON_MMAP_HPP_
#define _COMMON_MMAP_HPP_
#include <fcntl.h> 
#include <sys/stat.h> 
#include <unistd.h> 
#include <cstring>
#include <sys/mman.h>
#include <common/string.hpp>

class MemoryMappedFile
{
  public:
    enum CreationFlags{ReadOnly,ReadWrite};
    MemoryMappedFile(const String& pathFileName,CreationFlags creationFlags);
    virtual ~MemoryMappedFile();
    bool open(const String& pathFileName,CreationFlags creationFlags);
    bool readLine(String &strLine);
    char readChar(void);
    bool eof(void);
    char peekChar(void);
    void close(void);
    bool isOkay(void);
    off_t tell(void); 
  private:
    enum {CarriageReturn=0x0D,LineFeed=0x0A,NullChar=0x00};  
    enum {BlockSize=65536};
    bool createMemoryMap(void);
    int getFileAccessFromFlags(CreationFlags creationFlags)const;
    int getMemoryMapAccessFromFlags(CreationFlags creationFlags)const;

    int mFD = -1;
    unsigned long mIndex;
    off_t mFileLength = -1;
    char *mlpMappedDataBase = 0;
    CreationFlags mCreationFlags;
};

/// @brief 
/// @param pathFileName 
/// @param access
inline 
MemoryMappedFile::MemoryMappedFile(const String& pathFileName,CreationFlags creationFlags)
{
  open(pathFileName, creationFlags);
}

inline
MemoryMappedFile::~MemoryMappedFile()
{
}

inline
char MemoryMappedFile::readChar()
{
  return mlpMappedDataBase[mIndex++];
}

inline
bool MemoryMappedFile::eof()
{
  return mIndex<mFileLength?false:true;
}

inline 
char MemoryMappedFile::peekChar()
{
  return mlpMappedDataBase[mIndex];
}

inline
off_t MemoryMappedFile::tell(void)
{
  return mIndex;
} 

inline
bool MemoryMappedFile::readLine(String &strLine)
{
  off_t beginPosition = mIndex;
  while(mIndex<mFileLength && !(LineFeed==mlpMappedDataBase[mIndex++]));
  off_t currentPosition = mIndex;
  if(beginPosition==currentPosition)return false;
  off_t length = (currentPosition - beginPosition) -1;
  strLine.reserve(length<<1,0);
  ::memcpy((char*)strLine,mlpMappedDataBase+beginPosition,length);
  *((char*)strLine+length)=0;
  return true;
}

inline
bool MemoryMappedFile::isOkay(void)
{
    return -1==mFD?false:true;
}

#endif