compat/win32mmap.c

   1 #include "../git-compat-util.h"
   2
   3 void *git_mmap(void *start, size_t length, int prot, int flags, int fd, off_t offset)
   4 {
   5         HANDLE hmap;
   6         void *temp;
   7         off_t len;
   8         struct stat st;
   9         uint64_t o = offset;
  10         uint32_t l = o & 0xFFFFFFFF;
  11         uint32_t h = (o >> 32) & 0xFFFFFFFF;
  12
  13         if (!fstat(fd, &st))
  14                 len = st.st_size;
  15         else
  16                 die("mmap: could not determine filesize");
  17
  18         if ((length + offset) > len)
  19                 length = xsize_t(len - offset);
  20
  21         if (!(flags & MAP_PRIVATE))
  22                 die("Invalid usage of mmap when built with USE_WIN32_MMAP");
  23
  24         hmap = CreateFileMapping((HANDLE)_get_osfhandle(fd), 0, PAGE_WRITECOPY,
  25                 0, 0, 0);
  26
  27         if (!hmap)
  28                 return MAP_FAILED;
  29
  30         temp = MapViewOfFileEx(hmap, FILE_MAP_COPY, h, l, length, start);
  31
  32         if (!CloseHandle(hmap))
  33                 warning("unable to close file mapping handle\n");
  34
  35         return temp ? temp : MAP_FAILED;
  36 }
  37
  38 int git_munmap(void *start, size_t length)
  39 {
  40         return !UnmapViewOfFile(start);
  41 }