GIT_INLINE(int) pack_window_contains(git_mwindow *win, off_t offset)
{
/* We must promise at least 20 bytes (one hash) after the
* offset is available from this window, otherwise the offset
* is not actually in this window and a different window (which
* has that one hash excess) must be used. This is to support
* the object header and delta base parsing routines below.
*/
return git_mwindow_contains(win, offset + 20);
}
/*
* Open a new window, closing the least recenty used until we have
* enough space. Don't forget to add it to your list
*/
unsigned char *git_mwindow_open(git_mwindow_file *mwf, git_mwindow **cursor,
git_off_t offset, int extra, unsigned int *left)
{
git_mwindow *w = *cursor;
if (!w || !git_mwindow_contains(w, offset + extra)) {
if (w) {
w->inuse_cnt--;
}
for (w = mwf->windows; w; w = w->next) {
if (git_mwindow_contains(w, offset + extra))
break;
}
/*
* If there isn't a suitable window, we need to create a new
* one.
*/
if (!w) {
w = new_window(mwf, mwf->fd, mwf->size, offset);
if (w == NULL)
return NULL;
w->next = mwf->windows;
mwf->windows = w;
}
}
/* If we changed w, store it in the cursor */
if (w != *cursor) {
w->last_used = ctl.used_ctr++;
w->inuse_cnt++;
*cursor = w;
}
offset -= w->offset;
assert(git__is_sizet(offset));
if (left)
*left = (unsigned int)(w->window_map.len - offset);
return (unsigned char *) w->window_map.data + offset;
}