mapfile.c

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/* Copyright 2013 Jorge Merlino

   This file is part of Context.

   Context 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.

   Context 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with Context.  If not, see <http://www.gnu.org/licenses/>.
*/
 
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include "mapfile.h"
#include "debug.h"

#ifdef WIN32

#include <io.h>


static int fileOpen(char *name, Uint *textlen, BOOL writefile)
{
  int fd;
  struct stat buf;

  if((fd = _open(name,(writefile) ? O_RDWR : O_RDONLY)) == -1)
  {
     fprintf(stderr,"fileOpen: Cannot open \"%s\"",name);
     return -1;
  }
  if(fstat(fd,&buf) == -1)
  {
     fprintf(stderr, "file \"%s\": fstat(fd = %d) failed",name,fd);
     return -2;
  }
  *textlen = (Uint) buf.st_size;
  return fd;
}


static void * fileParts(int fd, Uint offset, Uint len, HANDLE *hndl, BOOL writemap) {
  void * ret;

  *hndl = CreateFileMapping (
                 (HANDLE)_get_osfhandle(fd),
                 NULL,
                 (writemap ? PAGE_READWRITE : PAGE_READONLY),
                 0,
                 0,
                 NULL);
    
  if (*hndl == NULL) {
    fprintf(stderr, "fileParts(fd = %d, left = %ld, len = %ld, %s) failed",fd,
            (long) offset, (long) len, writemap ? "writable map" : "readable map");
  }

  ret = (void *)MapViewOfFile (
                   *hndl, 
                   (writemap ? FILE_MAP_WRITE : FILE_MAP_READ),
                   0, 
                   offset, 
                   len);
  if (ret == NULL) {
    fprintf(stderr, "fileParts(fd = %d, left = %ld, len = %ld, %s) failed",fd,
            (long) offset, (long) len, writemap ? "writable map" : "readable map");
  }

  return ret;
}


static void * genfile2String(char *name, Uint *textlen, HANDLE *hndl, BOOL writefile, BOOL writemap) {
  int fd;

  fd = fileOpen(name, textlen, writefile);
  if(fd < 0)
  {
    return NULL;
  }
  return fileParts(fd, 0, *textlen, hndl, writemap);
}


void freetextspace(Uchar *text, HANDLE hndl) {
  if (!(UnmapViewOfFile(text))) {
    fprintf(stderr, "Unable to unmap file");
  }
  if (!CloseHandle(hndl)) {
    fprintf(stderr, "Unable to close handle");
  }
}


void * file2String(char *name, Uint *textlen, HANDLE *hndl) {
  return genfile2String(name, textlen, hndl, False, False);
}


#else /* UNIX */

#include <sys/mman.h>


static int fileOpen(char *name, Uint *textlen, BOOL writefile)
{
  int fd;
  struct stat buf;

  if((fd = open(name,(writefile) ? O_RDWR : O_RDONLY)) == -1)
  {
     fprintf(stderr,"fileOpen: Cannot open \"%s\"",name);
     return -1;
  }
  if(fstat(fd,&buf) == -1)
  {
     fprintf(stderr, "file \"%s\": fstat(fd = %d) failed",name,fd);
     return -2;
  }
  *textlen = (Uint) buf.st_size;
  return fd;
}


static void * fileParts(int fd, Uint offset, Uint len, BOOL writemap)
{
  void *addr;

  addr = mmap((void *) 0, (size_t) len, writemap ? (PROT_READ | PROT_WRITE) : PROT_READ, MAP_PRIVATE, fd, (off_t) offset);
  if(addr == (void *) MAP_FAILED)
  {
    fprintf(stderr, "fileParts(fd = %d, left = %ld, len = %ld, %s) failed",fd,
            (long) offset,(long) len,
            writemap ? "writable map" : "readable map");
    return NULL;
  } 
  return addr;
}


static void * genfile2String(char *name, Uint *textlen, BOOL writefile, BOOL writemap) {
  int fd;

  fd = fileOpen(name, textlen, writefile);
  if(fd < 0)
  {
    return NULL;
  }
  return fileParts(fd, 0, *textlen, writemap);
}


void freetextspace(Uchar *text, Uint textlen) {
  if (munmap((void *) text, (size_t) textlen) == -1) {
    fprintf(stderr, "Unable to unmap file");
  }
}


void * file2String(char *name, Uint *textlen) {
  return genfile2String(name, textlen, False, False);
}

#endif