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
180
181
182
183
184
185
186
187
188
189
190
191
192
193
|
///////////////////////////////////////////////////////////////////////////////
//
/// \file 03_compress_custom.c
/// \brief Compress in multi-call mode using x86 BCJ and LZMA2
///
/// Usage: ./03_compress_custom < INFILE > OUTFILE
///
/// Example: ./03_compress_custom < foo > foo.xz
//
// Author: Lasse Collin
//
// This file has been put into the public domain.
// You can do whatever you want with this file.
//
///////////////////////////////////////////////////////////////////////////////
#include <stdbool.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <lzma.h>
static bool
init_encoder(lzma_stream *strm)
{
// Use the default preset (6) for LZMA2.
//
// The lzma_options_lzma structure and the lzma_lzma_preset() function
// are declared in lzma/lzma12.h (src/liblzma/api/lzma/lzma12.h in the
// source package or e.g. /usr/include/lzma/lzma12.h depending on
// the install prefix).
lzma_options_lzma opt_lzma2;
if (lzma_lzma_preset(&opt_lzma2, LZMA_PRESET_DEFAULT)) {
// It should never fail because the default preset
// (and presets 0-9 optionally with LZMA_PRESET_EXTREME)
// are supported by all stable liblzma versions.
//
// (The encoder initialization later in this function may
// still fail due to unsupported preset *if* the features
// required by the preset have been disabled at build time,
// but no-one does such things except on embedded systems.)
fprintf(stderr, "Unsupported preset, possibly a bug\n");
return false;
}
// Now we could customize the LZMA2 options if we wanted. For example,
// we could set the the dictionary size (opt_lzma2.dict_size) to
// something else than the default (8 MiB) of the default preset.
// See lzma/lzma12.h for details of all LZMA2 options.
//
// The x86 BCJ filter will try to modify the x86 instruction stream so
// that LZMA2 can compress it better. The x86 BCJ filter doesn't need
// any options so it will be set to NULL below.
//
// Construct the filter chain. The uncompressed data goes first to
// the first filter in the array, in this case the x86 BCJ filter.
// The array is always terminated by setting .id = LZMA_VLI_UNKNOWN.
//
// See lzma/filter.h for more information about the lzma_filter
// structure.
lzma_filter filters[] = {
{ .id = LZMA_FILTER_X86, .options = NULL },
{ .id = LZMA_FILTER_LZMA2, .options = &opt_lzma2 },
{ .id = LZMA_VLI_UNKNOWN, .options = NULL },
};
// Initialize the encoder using the custom filter chain.
lzma_ret ret = lzma_stream_encoder(strm, filters, LZMA_CHECK_CRC64);
if (ret == LZMA_OK)
return true;
const char *msg;
switch (ret) {
case LZMA_MEM_ERROR:
msg = "Memory allocation failed";
break;
case LZMA_OPTIONS_ERROR:
// We are no longer using a plain preset so this error
// message has been edited accordingly compared to
// 01_compress_easy.c.
msg = "Specified filter chain is not supported";
break;
case LZMA_UNSUPPORTED_CHECK:
msg = "Specified integrity check is not supported";
break;
default:
msg = "Unknown error, possibly a bug";
break;
}
fprintf(stderr, "Error initializing the encoder: %s (error code %u)\n",
msg, ret);
return false;
}
// This function is identical to the one in 01_compress_easy.c.
static bool
compress(lzma_stream *strm, FILE *infile, FILE *outfile)
{
lzma_action action = LZMA_RUN;
uint8_t inbuf[BUFSIZ];
uint8_t outbuf[BUFSIZ];
strm->next_in = NULL;
strm->avail_in = 0;
strm->next_out = outbuf;
strm->avail_out = sizeof(outbuf);
while (true) {
if (strm->avail_in == 0 && !feof(infile)) {
strm->next_in = inbuf;
strm->avail_in = fread(inbuf, 1, sizeof(inbuf),
infile);
if (ferror(infile)) {
fprintf(stderr, "Read error: %s\n",
strerror(errno));
return false;
}
if (feof(infile))
action = LZMA_FINISH;
}
lzma_ret ret = lzma_code(strm, action);
if (strm->avail_out == 0 || ret == LZMA_STREAM_END) {
size_t write_size = sizeof(outbuf) - strm->avail_out;
if (fwrite(outbuf, 1, write_size, outfile)
!= write_size) {
fprintf(stderr, "Write error: %s\n",
strerror(errno));
return false;
}
strm->next_out = outbuf;
strm->avail_out = sizeof(outbuf);
}
if (ret != LZMA_OK) {
if (ret == LZMA_STREAM_END)
return true;
const char *msg;
switch (ret) {
case LZMA_MEM_ERROR:
msg = "Memory allocation failed";
break;
case LZMA_DATA_ERROR:
msg = "File size limits exceeded";
break;
default:
msg = "Unknown error, possibly a bug";
break;
}
fprintf(stderr, "Encoder error: %s (error code %u)\n",
msg, ret);
return false;
}
}
}
extern int
main(void)
{
lzma_stream strm = LZMA_STREAM_INIT;
bool success = init_encoder(&strm);
if (success)
success = compress(&strm, stdin, stdout);
lzma_end(&strm);
if (fclose(stdout)) {
fprintf(stderr, "Write error: %s\n", strerror(errno));
success = false;
}
return success ? EXIT_SUCCESS : EXIT_FAILURE;
}
|
