//
//  CRF++ -- Yet Another CRF toolkit
//
//  $Id: mmap.h 1588 2007-02-12 09:03:39Z taku $;
//
//  Copyright(C) 2005-2007 Taku Kudo <taku@chasen.org>
//
#ifndef CRFPP_MMAP_H__
#define CRFPP_MMAP_H__

#include <errno.h>
#include <string>

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

extern "C" {

#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif

#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif

#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif

#ifdef HAVE_STRING_H
#include <string.h>
#endif

#if defined(_WIN32) && !defined(__CYGWIN__)
#ifdef HAVE_WINDOWS_H
#include <windows.h>
#endif
#else

#ifdef HAVE_SYS_MMAN_H
#include <sys/mman.h>
#endif

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#endif
}

#include "common.h"

#ifndef O_BINARY
#define O_BINARY 0
#endif

#if !defined(_WIN32) || defined(__CYGWIN__)
namespace {
  int open__(const char* name, int flag) { return open(name, flag); }
  int close__(int fd) { return close(fd); }
}
#endif

namespace CRFPP {

  template <class T> class Mmap {
  private:
    T            *text;
    size_t       length;
    std::string  fileName;
    whatlog what_;

#if defined(_WIN32) && !defined(__CYGWIN__)
    HANDLE hFile;
    HANDLE hMap;
#else
    int    fd;
    int    flag;
#endif

  public:
    T&       operator[](size_t n)       { return *(text + n); }
    const T& operator[](size_t n) const { return *(text + n); }
    T*       begin()           { return text; }
    const T* begin()    const  { return text; }
    T*       end()           { return text + size(); }
    const T* end()    const  { return text + size(); }
    size_t size()               { return length/sizeof(T); }
    const char *what()          { return what_.str(); }
    const char *file_name()     { return fileName.c_str(); }
    size_t file_size()          { return length; }
    bool empty()                { return(length == 0); }

    // This code is imported from sufary, develoved by
    //  TATUO Yamashita <yto@nais.to> Thanks!
#if defined(_WIN32) && !defined(__CYGWIN__)
    bool open(const char *filename, const char *mode = "r") {
      this->close();
      unsigned long mode1, mode2, mode3;
      fileName = std::string(filename);

      if (std::strcmp(mode, "r") == 0) {
        mode1 = GENERIC_READ;
        mode2 = PAGE_READONLY;
        mode3 = FILE_MAP_READ;
      } else if (std::strcmp(mode, "r+") == 0) {
        mode1 = GENERIC_READ | GENERIC_WRITE;
        mode2 = PAGE_READWRITE;
        mode3 = FILE_MAP_ALL_ACCESS;
      } else {
        CHECK_CLOSE_FALSE(false) << "unknown open mode:" << filename;
      }

      hFile = CreateFile(filename, mode1, FILE_SHARE_READ, 0,
                         OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);
      CHECK_CLOSE_FALSE(hFile != INVALID_HANDLE_VALUE)
        << "CreateFile() failed: " << filename;

      length = GetFileSize(hFile, 0);

      hMap = CreateFileMapping(hFile, 0, mode2, 0, 0, 0);
      CHECK_CLOSE_FALSE(hMap) << "CreateFileMapping() failed: " << filename;

      text = reinterpret_cast<T *>(MapViewOfFile(hMap, mode3, 0, 0, 0));
      CHECK_CLOSE_FALSE(text) << "MapViewOfFile() failed: " << filename;

      return true;
    }

    void close() {
      if (text) { UnmapViewOfFile(text); }
      if (hFile != INVALID_HANDLE_VALUE) {
        CloseHandle(hFile);
        hFile = INVALID_HANDLE_VALUE;
      }
      if (hMap) {
        CloseHandle(hMap);
        hMap = 0;
      }
      text = 0;
    }

    Mmap(): text(0), hFile(INVALID_HANDLE_VALUE), hMap(0) {}

#else

    bool open(const char *filename, const char *mode = "r") {
      this->close();
      struct stat st;
      fileName = std::string(filename);

      if      (std::strcmp(mode, "r") == 0)
        flag = O_RDONLY;
      else if (std::strcmp(mode, "r+") == 0)
        flag = O_RDWR;
      else
        CHECK_CLOSE_FALSE(false) << "unknown open mode: " << filename;

      CHECK_CLOSE_FALSE((fd = open__(filename, flag | O_BINARY)) >= 0)
        << "open failed: " << filename;

      CHECK_CLOSE_FALSE(fstat(fd, &st) >= 0)
        << "failed to get file size: " << filename;

      length = st.st_size;

#ifdef HAVE_MMAP
      int prot = PROT_READ;
      if (flag == O_RDWR) prot |= PROT_WRITE;
      char *p;
      CHECK_CLOSE_FALSE((p = reinterpret_cast<char *>
                         (mmap(0, length, prot, MAP_SHARED, fd, 0)))
                        != MAP_FAILED)
        << "mmap() failed: " << filename;

      text = reinterpret_cast<T *>(p);
#else
      text = new T[length];
      CHECK_CLOSE_FALSE(read(fd, text, length) >= 0)
        << "read() failed: " << filename;
#endif
      close__(fd);
      fd = -1;

      return true;
    }

    void close() {
      if (fd >= 0) {
        close__(fd);
        fd = -1;
      }

      if (text) {
#ifdef HAVE_MMAP
        munmap(reinterpret_cast<char *>(text), length);
        text = 0;
#else
        if (flag == O_RDWR) {
          int fd2;
          if ((fd2 = open__(fileName.c_str(), O_RDWR)) >= 0) {
            write(fd2, text, length);
            close__(fd2);
          }
        }
        delete [] text;
#endif
      }

      text = 0;
    }

    Mmap(): text(0), fd(-1) {}
#endif

    virtual ~Mmap() { this->close(); }
  };
}
#endif