File: bzip2.c

package info (click to toggle)
busybox 1:1.17.1-8+deb6u11
  • links: PTS
  • area: main
  • in suites: squeeze-lts
  • size: 15,608 kB
  • ctags: 26,465
  • sloc: ansic: 182,252; sh: 6,047; cpp: 1,428; makefile: 1,031; yacc: 570; lex: 355; perl: 309; python: 251; awk: 29
file content (179 lines) | stat: -rw-r--r-- 4,686 bytes parent folder | download | duplicates (2)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
/*
 * Copyright (C) 2007 Denys Vlasenko <vda.linux@googlemail.com>
 *
 * This file uses bzip2 library code which is written
 * by Julian Seward <jseward@bzip.org>.
 * See README and LICENSE files in bz/ directory for more information
 * about bzip2 library code.
 */

#include "libbb.h"
#include "unarchive.h"

#define CONFIG_BZIP2_FEATURE_SPEED 1

/* Speed test:
 * Compiled with gcc 4.2.1, run on Athlon 64 1800 MHz (512K L2 cache).
 * Stock bzip2 is 26.4% slower than bbox bzip2 at SPEED 1
 * (time to compress gcc-4.2.1.tar is 126.4% compared to bbox).
 * At SPEED 5 difference is 32.7%.
 *
 * Test run of all CONFIG_BZIP2_FEATURE_SPEED values on a 11Mb text file:
 *     Size   Time (3 runs)
 * 0:  10828  4.145 4.146 4.148
 * 1:  11097  3.845 3.860 3.861
 * 2:  11392  3.763 3.767 3.768
 * 3:  11892  3.722 3.724 3.727
 * 4:  12740  3.637 3.640 3.644
 * 5:  17273  3.497 3.509 3.509
 */


#define BZ_DEBUG 0
/* Takes ~300 bytes, detects corruption caused by bad RAM etc */
#define BZ_LIGHT_DEBUG 0

#include "bz/bzlib.h"

#include "bz/bzlib_private.h"

#include "bz/blocksort.c"
#include "bz/bzlib.c"
#include "bz/compress.c"
#include "bz/huffman.c"

/* No point in being shy and having very small buffer here.
 * bzip2 internal buffers are much bigger anyway, hundreds of kbytes.
 * If iobuf is several pages long, malloc() may use mmap,
 * making iobuf is page aligned and thus (maybe) have one memcpy less
 * if kernel is clever enough.
 */
enum {
	IOBUF_SIZE = 8 * 1024
};

static uint8_t level;

/* NB: compressStream() has to return -1 on errors, not die.
 * bbunpack() will correctly clean up in this case
 * (delete incomplete .bz2 file)
 */

/* Returns:
 * -1 on errors
 * total written bytes so far otherwise
 */
static
IF_DESKTOP(long long) int bz_write(bz_stream *strm, void* rbuf, ssize_t rlen, void *wbuf)
{
	int n, n2, ret;

	strm->avail_in = rlen;
	strm->next_in = rbuf;
	while (1) {
		strm->avail_out = IOBUF_SIZE;
		strm->next_out = wbuf;

		ret = BZ2_bzCompress(strm, rlen ? BZ_RUN : BZ_FINISH);
		if (ret != BZ_RUN_OK /* BZ_RUNning */
		 && ret != BZ_FINISH_OK /* BZ_FINISHing, but not done yet */
		 && ret != BZ_STREAM_END /* BZ_FINISHed */
		) {
			bb_error_msg_and_die("internal error %d", ret);
		}

		n = IOBUF_SIZE - strm->avail_out;
		if (n) {
			n2 = full_write(STDOUT_FILENO, wbuf, n);
			if (n2 != n) {
				if (n2 >= 0)
					errno = 0; /* prevent bogus error message */
				bb_perror_msg(n2 >= 0 ? "short write" : bb_msg_write_error);
				return -1;
			}
		}

		if (ret == BZ_STREAM_END)
			break;
		if (rlen && strm->avail_in == 0)
			break;
	}
	return 0 IF_DESKTOP( + strm->total_out );
}

static
IF_DESKTOP(long long) int FAST_FUNC compressStream(unpack_info_t *info UNUSED_PARAM)
{
	IF_DESKTOP(long long) int total;
	ssize_t count;
	bz_stream bzs; /* it's small */
#define strm (&bzs)
	char *iobuf;
#define rbuf iobuf
#define wbuf (iobuf + IOBUF_SIZE)

	iobuf = xmalloc(2 * IOBUF_SIZE);
	BZ2_bzCompressInit(strm, level);

	while (1) {
		count = full_read(STDIN_FILENO, rbuf, IOBUF_SIZE);
		if (count < 0) {
			bb_perror_msg(bb_msg_read_error);
			total = -1;
			break;
		}
		/* if count == 0, bz_write finalizes compression */
		total = bz_write(strm, rbuf, count, wbuf);
		if (count == 0 || total < 0)
			break;
	}

#if ENABLE_FEATURE_CLEAN_UP
	BZ2_bzCompressEnd(strm);
	free(iobuf);
#endif
	return total;
}

int bzip2_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int bzip2_main(int argc UNUSED_PARAM, char **argv)
{
	unsigned opt;

	/* standard bzip2 flags
	 * -d --decompress force decompression
	 * -z --compress force compression
	 * -k --keep     keep (don't delete) input files
	 * -f --force    overwrite existing output files
	 * -t --test     test compressed file integrity
	 * -c --stdout   output to standard out
	 * -q --quiet    suppress noncritical error messages
	 * -v --verbose  be verbose (a 2nd -v gives more)
	 * -s --small    use less memory (at most 2500k)
	 * -1 .. -9      set block size to 100k .. 900k
	 * --fast        alias for -1
	 * --best        alias for -9
	 */

	opt_complementary = "s2"; /* -s means -2 (compatibility) */
	/* Must match bbunzip's constants OPT_STDOUT, OPT_FORCE! */
	opt = getopt32(argv, "cfv" IF_BUNZIP2("dt") "123456789qzs");
#if ENABLE_BUNZIP2 /* bunzip2_main may not be visible... */
	if (opt & 0x18) // -d and/or -t
		return bunzip2_main(argc, argv);
	opt >>= 5;
#else
	opt >>= 3;
#endif
	opt = (uint8_t)opt; /* isolate bits for -1..-8 */
	opt |= 0x100; /* if nothing else, assume -9 */
	level = 1;
	while (!(opt & 1)) {
		level++;
		opt >>= 1;
	}

	argv += optind;
	option_mask32 &= 0x7; /* ignore all except -cfv */
	return bbunpack(argv, compressStream, append_ext, "bz2");
}