1/*
2 * Simple XZ decoder command line tool
3 *
4 * Author: Lasse Collin <lasse.collin@tukaani.org>
5 *
6 * This file has been put into the public domain.
7 * You can do whatever you want with this file.
8 */
9
10/*
11 * This is really limited: Not all filters from .xz format are supported,
12 * only CRC32 is supported as the integrity check, and decoding of
13 * concatenated .xz streams is not supported. Thus, you may want to look
14 * at xzdec from XZ Utils if a few KiB bigger tool is not a problem.
15 */
16
17#include <stdbool.h>
18#include <stdio.h>
19#include <string.h>
20#include "xz.h"
21
22static uint8_t in[BUFSIZ];
23static uint8_t out[BUFSIZ];
24
25int main(int argc, char **argv)
26{
27	struct xz_buf b;
28	struct xz_dec *s;
29	enum xz_ret ret;
30	const char *msg;
31
32	if (argc >= 2 && strcmp(argv[1], "--help") == 0) {
33		fputs("Uncompress a .xz file from stdin to stdout.\n"
34				"Arguments other than `--help' are ignored.\n",
35				stdout);
36		return 0;
37	}
38
39	xz_crc32_init();
40#ifdef XZ_USE_CRC64
41	xz_crc64_init();
42#endif
43
44	/*
45	 * Support up to 64 MiB dictionary. The actually needed memory
46	 * is allocated once the headers have been parsed.
47	 */
48	s = xz_dec_init(XZ_DYNALLOC, 1 << 26);
49	if (s == NULL) {
50		msg = "Memory allocation failed\n";
51		goto error;
52	}
53
54	b.in = in;
55	b.in_pos = 0;
56	b.in_size = 0;
57	b.out = out;
58	b.out_pos = 0;
59	b.out_size = BUFSIZ;
60
61	while (true) {
62		if (b.in_pos == b.in_size) {
63			b.in_size = fread(in, 1, sizeof(in), stdin);
64			b.in_pos = 0;
65		}
66
67		ret = xz_dec_run(s, &b);
68
69		if (b.out_pos == sizeof(out)) {
70			if (fwrite(out, 1, b.out_pos, stdout) != b.out_pos) {
71				msg = "Write error\n";
72				goto error;
73			}
74
75			b.out_pos = 0;
76		}
77
78		if (ret == XZ_OK)
79			continue;
80
81#ifdef XZ_DEC_ANY_CHECK
82		if (ret == XZ_UNSUPPORTED_CHECK) {
83			fputs(argv[0], stderr);
84			fputs(": ", stderr);
85			fputs("Unsupported check; not verifying "
86					"file integrity\n", stderr);
87			continue;
88		}
89#endif
90
91		if (fwrite(out, 1, b.out_pos, stdout) != b.out_pos
92				|| fclose(stdout)) {
93			msg = "Write error\n";
94			goto error;
95		}
96
97		switch (ret) {
98		case XZ_STREAM_END:
99			xz_dec_end(s);
100			return 0;
101
102		case XZ_MEM_ERROR:
103			msg = "Memory allocation failed\n";
104			goto error;
105
106		case XZ_MEMLIMIT_ERROR:
107			msg = "Memory usage limit reached\n";
108			goto error;
109
110		case XZ_FORMAT_ERROR:
111			msg = "Not a .xz file\n";
112			goto error;
113
114		case XZ_OPTIONS_ERROR:
115			msg = "Unsupported options in the .xz headers\n";
116			goto error;
117
118		case XZ_DATA_ERROR:
119		case XZ_BUF_ERROR:
120			msg = "File is corrupt\n";
121			goto error;
122
123		default:
124			msg = "Bug!\n";
125			goto error;
126		}
127	}
128
129error:
130	xz_dec_end(s);
131	fputs(argv[0], stderr);
132	fputs(": ", stderr);
133	fputs(msg, stderr);
134	return 1;
135}
136