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
41	/*
42	 * Support up to 64 MiB dictionary. The actually needed memory
43	 * is allocated once the headers have been parsed.
44	 */
45	s = xz_dec_init(XZ_DYNALLOC, 1 << 26);
46	if (s == NULL) {
47		msg = "Memory allocation failed\n";
48		goto error;
49	}
50
51	b.in = in;
52	b.in_pos = 0;
53	b.in_size = 0;
54	b.out = out;
55	b.out_pos = 0;
56	b.out_size = BUFSIZ;
57
58	while (true) {
59		if (b.in_pos == b.in_size) {
60			b.in_size = fread(in, 1, sizeof(in), stdin);
61			b.in_pos = 0;
62		}
63
64		ret = xz_dec_run(s, &b);
65
66		if (b.out_pos == sizeof(out)) {
67			if (fwrite(out, 1, b.out_pos, stdout) != b.out_pos) {
68				msg = "Write error\n";
69				goto error;
70			}
71
72			b.out_pos = 0;
73		}
74
75		if (ret == XZ_OK)
76			continue;
77
78#ifdef XZ_DEC_ANY_CHECK
79		if (ret == XZ_UNSUPPORTED_CHECK) {
80			fputs(argv[0], stderr);
81			fputs(": ", stderr);
82			fputs("Unsupported check; not verifying "
83					"file integrity\n", stderr);
84			continue;
85		}
86#endif
87
88		if (fwrite(out, 1, b.out_pos, stdout) != b.out_pos
89				|| fclose(stdout)) {
90			msg = "Write error\n";
91			goto error;
92		}
93
94		switch (ret) {
95		case XZ_STREAM_END:
96			xz_dec_end(s);
97			return 0;
98
99		case XZ_MEM_ERROR:
100			msg = "Memory allocation failed\n";
101			goto error;
102
103		case XZ_MEMLIMIT_ERROR:
104			msg = "Memory usage limit reached\n";
105			goto error;
106
107		case XZ_FORMAT_ERROR:
108			msg = "Not a .xz file\n";
109			goto error;
110
111		case XZ_OPTIONS_ERROR:
112			msg = "Unsupported options in the .xz headers\n";
113			goto error;
114
115		case XZ_DATA_ERROR:
116		case XZ_BUF_ERROR:
117			msg = "File is corrupt\n";
118			goto error;
119
120		default:
121			msg = "Bug!\n";
122			goto error;
123		}
124	}
125
126error:
127	xz_dec_end(s);
128	fputs(argv[0], stderr);
129	fputs(": ", stderr);
130	fputs(msg, stderr);
131	return 1;
132}
133