Andrew's git - gitweb.git/blob - compat/win32mmap.c

   1#include "../git-compat-util.h"
   2
   3/*
   4 * Note that this doesn't return the actual pagesize, but
   5 * the allocation granularity. If future Windows specific git code
   6 * needs the real getpagesize function, we need to find another solution.
   7 */
   8int mingw_getpagesize(void)
   9{
  10        SYSTEM_INFO si;
  11        GetSystemInfo(&si);
  12        return si.dwAllocationGranularity;
  13}
  14
  15void *git_mmap(void *start, size_t length, int prot, int flags, int fd, off_t offset)
  16{
  17        HANDLE hmap;
  18        void *temp;
  19        size_t len;
  20        struct stat st;
  21        uint64_t o = offset;
  22        uint32_t l = o & 0xFFFFFFFF;
  23        uint32_t h = (o >> 32) & 0xFFFFFFFF;
  24
  25        if (!fstat(fd, &st))
  26                len = xsize_t(st.st_size);
  27        else
  28                die("mmap: could not determine filesize");
  29
  30        if ((length + offset) > len)
  31                length = len - offset;
  32
  33        if (!(flags & MAP_PRIVATE))
  34                die("Invalid usage of mmap when built with USE_WIN32_MMAP");
  35
  36        hmap = CreateFileMapping((HANDLE)_get_osfhandle(fd), 0, PAGE_WRITECOPY,
  37                0, 0, 0);
  38
  39        if (!hmap)
  40                return MAP_FAILED;
  41
  42        temp = MapViewOfFileEx(hmap, FILE_MAP_COPY, h, l, length, start);
  43
  44        if (!CloseHandle(hmap))
  45                warning("unable to close file mapping handle\n");
  46
  47        return temp ? temp : MAP_FAILED;
  48}
  49
  50int git_munmap(void *start, size_t length)
  51{
  52        return !UnmapViewOfFile(start);
  53}