1 /*
2  * Copyright (c) 2020 Ori Bernstein
3  * Copyright (c) 2021 Stefan Sperling <stsp@openbsd.org>
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 struct got_delta_block {
19 	off_t		len;
20 	off_t		offset;
21 	uint64_t	hash;
22 };
23 
24 struct got_delta_table {
25 	struct got_delta_block	*blocks;
26 	int			nblocks;
27 	int			nalloc;
28 };
29 
30 struct got_delta_instruction {
31 	int	copy;
32 	off_t	offset;
33 	off_t	len;
34 };
35 
36 enum {
37 	GOT_DELTIFY_MINCHUNK	= 128,
38 	GOT_DELTIFY_MAXCHUNK	= 8192,
39 	GOT_DELTIFY_SPLITMASK	= (1 << 8) - 1,
40 	
41 };
42 
43 const struct got_error *got_deltify_init(struct got_delta_table **dt, FILE *f,
44     off_t fileoffset, off_t filesize);
45 const struct got_error *got_deltify(struct got_delta_instruction **deltas,
46     int *ndeltas, FILE *f, off_t fileoffset, off_t filesize,
47     struct got_delta_table *dt, FILE *basefile, off_t basefile_size);
48 void got_deltify_free(struct got_delta_table *dt);