CPPUtil/UtilMappedFile.cpp

   1 //
   2 //  UtilMappedFile.cpp
   3 //  CPPUtil
   4 //
   5 //  Created by James McIlree on 4/19/13.
   6 //  Copyright (c) 2013 Apple. All rights reserved.
   7 //
   8
   9 #include "CPPUtil.h"
  10
  11 #include <sys/mman.h>
  12
  13 BEGIN_UTIL_NAMESPACE
  14
  15 static int open_fd(const char* path, size_t& file_size)
  16 {
  17         int fd = open(path, O_RDONLY, 0);
  18         if(fd >= 0) {
  19                 struct stat data;
  20                 if (fstat(fd, &data) == 0) {
  21                         if (S_ISREG(data.st_mode)) {
  22                                 // Is it zero sized?
  23                                 if (data.st_size > 0) {
  24                                         file_size = (size_t)data.st_size;
  25                                         return fd;
  26                                 }
  27                         }
  28                 }
  29                 close(fd);
  30         }
  31
  32         return -1;
  33 }
  34
  35 MappedFile::MappedFile(const char* path) :
  36         _address(NULL),
  37         _size(0)
  38 {
  39         ASSERT(path, "Sanity");
  40         int fd = open_fd(path, _size);
  41         if (fd >= 0) {
  42                 _address = (unsigned char*)mmap(NULL, _size, PROT_READ, MAP_FILE | MAP_SHARED, fd, 0);
  43                 if (_address == (void*)-1) {
  44                         _address = NULL;
  45                 }
  46                 close(fd);
  47         }
  48 }
  49
  50 MappedFile::~MappedFile()
  51 {
  52         if (_address != NULL) {
  53                 munmap(_address, _size);
  54         }
  55 }
  56
  57 END_UTIL_NAMESPACE