1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2022 Klara, Inc.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28/* This file is #included by gzip.c */
29
30static off_t
31unzstd(int in, int out, char *pre, size_t prelen, off_t *bytes_in)
32{
33	static char *ibuf, *obuf;
34	ZSTD_inBuffer zib;
35	ZSTD_outBuffer zob;
36	ZSTD_DCtx *zds;
37	ssize_t res;
38	size_t zres;
39	size_t bytes_out = 0;
40	int eof = 0;
41
42	if (ibuf == NULL)
43		ibuf = malloc(BUFLEN);
44	if (obuf == NULL)
45		obuf = malloc(BUFLEN);
46	if (ibuf == NULL || obuf == NULL)
47		maybe_err("malloc");
48
49	zds = ZSTD_createDStream();
50	ZSTD_initDStream(zds);
51
52	zib.src = pre;
53	zib.size = prelen;
54	zib.pos = 0;
55	if (bytes_in != NULL)
56		*bytes_in = prelen;
57	zob.dst = obuf;
58	zob.size = BUFLEN;
59	zob.pos = 0;
60
61	while (!eof) {
62		if (zib.pos >= zib.size) {
63			res = read(in, ibuf, BUFLEN);
64			if (res < 0)
65				maybe_err("read");
66			if (res == 0)
67				eof = 1;
68			infile_newdata(res);
69			zib.src = ibuf;
70			zib.size = res;
71			zib.pos = 0;
72			if (bytes_in != NULL)
73				*bytes_in += res;
74		}
75		zres = ZSTD_decompressStream(zds, &zob, &zib);
76		if (ZSTD_isError(zres)) {
77			maybe_errx("%s", ZSTD_getErrorName(zres));
78		}
79		if (zob.pos > 0) {
80			res = write(out, obuf, zob.pos);
81			if (res < 0)
82				maybe_err("write");
83			zob.pos = 0;
84			bytes_out += res;
85		}
86	}
87	ZSTD_freeDStream(zds);
88	return (bytes_out);
89}
90