root/compat/win32mmap.c

DEFINITIONS

1. git_mmap
2. git_munmap

#include "../git-compat-util.h"

void *git_mmap(void *start, size_t length, int prot, int flags, int fd, off_t offset)
{
        HANDLE hmap;
        void *temp;
        off_t len;
        struct stat st;
        uint64_t o = offset;
        uint32_t l = o & 0xFFFFFFFF;
        uint32_t h = (o >> 32) & 0xFFFFFFFF;

        if (!fstat(fd, &st))
                len = st.st_size;
        else
                die("mmap: could not determine filesize");

        if ((length + offset) > len)
                length = xsize_t(len - offset);

        if (!(flags & MAP_PRIVATE))
                die("Invalid usage of mmap when built with USE_WIN32_MMAP");

        hmap = CreateFileMapping((HANDLE)_get_osfhandle(fd), NULL,
                PAGE_WRITECOPY, 0, 0, NULL);

        if (!hmap)
                return MAP_FAILED;

        temp = MapViewOfFileEx(hmap, FILE_MAP_COPY, h, l, length, start);

        if (!CloseHandle(hmap))
                warning("unable to close file mapping handle");

        return temp ? temp : MAP_FAILED;
}

int git_munmap(void *start, size_t length)
{
        return !UnmapViewOfFile(start);
}