static int write_at(git_indexer *idx, const void *data, git_off_t offset, size_t size)
{
git_file fd = idx->pack->mwf.fd;
size_t page_size;
size_t page_offset;
git_off_t page_start;
unsigned char *map_data;
git_map map;
int error;
assert(data && size);
if ((error = git__page_size(&page_size)) < 0)
return error;
/* the offset needs to be at the beginning of the a page boundary */
page_offset = offset % page_size;
page_start = offset - page_offset;
if ((error = p_mmap(&map, page_offset + size, GIT_PROT_WRITE, GIT_MAP_SHARED, fd, page_start)) < 0)
return error;
map_data = (unsigned char *)map.data;
memcpy(map_data + page_offset, data, size);
p_munmap(&map);
return 0;
}
int git__mmap_alignment(size_t *alignment)
{
return git__page_size(alignment);
}
