xref: /freebsd/usr.bin/gzip/unzstd.c (revision 2e3f49888ec8851bafb22011533217487764fdb0)
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 
30 static off_t
31 unzstd(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