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#ifndef FILE_SNAPSHOT_H
#define FILE_SNAPSHOT_H
struct snapshot
{
int data_size;
int num_items;
struct item
{
int type_and_id;
int *data() { return (int *)(this+1); }
int type() { return type_and_id>>16; }
int id() { return type_and_id&(0xffff); }
int key() { return type_and_id; }
};
int *offsets() { return (int *)(this+1); }
char *data_start() { return (char *)(offsets() + num_items); }
item *get_item(int index) { return (item *)(data_start() + offsets()[index]); };
// returns the number of ints in the item data
int get_item_datasize(int index)
{
if(index == num_items-1)
return (data_size - offsets()[index]) - sizeof(item);
return (offsets()[index+1] - offsets()[index]) - sizeof(item);
}
int get_item_index(int key)
{
// TODO: this should not be a linear search. very bad
for(int i = 0; i < num_items; i++)
{
if(get_item(i)->key() == key)
return i;
}
return -1;
}
};
void *snapshot_empty_delta();
int snapshot_create_delta(snapshot *from, snapshot *to, void *data);
int snapshot_unpack_delta(snapshot *from, snapshot *to, void *data, int data_size);
#endif // FILE_SNAPSHOT_H
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