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
|
///////////////////////////////////////////////////////////////////////////////
//
/// \file auto_decoder.c
/// \brief Autodetect between .xz Stream and .lzma (LZMA_Alone) formats
//
// Author: Lasse Collin
//
// This file has been put into the public domain.
// You can do whatever you want with this file.
//
///////////////////////////////////////////////////////////////////////////////
#include "stream_decoder.h"
#include "alone_decoder.h"
struct lzma_coder_s {
/// Stream decoder or LZMA_Alone decoder
lzma_next_coder next;
uint64_t memlimit;
uint32_t flags;
enum {
SEQ_INIT,
SEQ_CODE,
SEQ_FINISH,
} sequence;
};
static lzma_ret
auto_decode(lzma_coder *coder, const lzma_allocator *allocator,
const uint8_t *restrict in, size_t *restrict in_pos,
size_t in_size, uint8_t *restrict out,
size_t *restrict out_pos, size_t out_size, lzma_action action)
{
switch (coder->sequence) {
case SEQ_INIT:
if (*in_pos >= in_size)
return LZMA_OK;
// Update the sequence now, because we want to continue from
// SEQ_CODE even if we return some LZMA_*_CHECK.
coder->sequence = SEQ_CODE;
// Detect the file format. For now this is simple, since if
// it doesn't start with 0xFD (the first magic byte of the
// new format), it has to be LZMA_Alone, or something that
// we don't support at all.
if (in[*in_pos] == 0xFD) {
return_if_error(lzma_stream_decoder_init(
&coder->next, allocator,
coder->memlimit, coder->flags));
} else {
return_if_error(lzma_alone_decoder_init(&coder->next,
allocator, coder->memlimit, true));
// If the application wants to know about missing
// integrity check or about the check in general, we
// need to handle it here, because LZMA_Alone decoder
// doesn't accept any flags.
if (coder->flags & LZMA_TELL_NO_CHECK)
return LZMA_NO_CHECK;
if (coder->flags & LZMA_TELL_ANY_CHECK)
return LZMA_GET_CHECK;
}
// Fall through
case SEQ_CODE: {
const lzma_ret ret = coder->next.code(
coder->next.coder, allocator,
in, in_pos, in_size,
out, out_pos, out_size, action);
if (ret != LZMA_STREAM_END
|| (coder->flags & LZMA_CONCATENATED) == 0)
return ret;
coder->sequence = SEQ_FINISH;
}
// Fall through
case SEQ_FINISH:
// When LZMA_DECODE_CONCATENATED was used and we were decoding
// LZMA_Alone file, we need to check check that there is no
// trailing garbage and wait for LZMA_FINISH.
if (*in_pos < in_size)
return LZMA_DATA_ERROR;
return action == LZMA_FINISH ? LZMA_STREAM_END : LZMA_OK;
default:
assert(0);
return LZMA_PROG_ERROR;
}
}
static void
auto_decoder_end(lzma_coder *coder, const lzma_allocator *allocator)
{
lzma_next_end(&coder->next, allocator);
lzma_free(coder, allocator);
return;
}
static lzma_check
auto_decoder_get_check(const lzma_coder *coder)
{
// It is LZMA_Alone if get_check is NULL.
return coder->next.get_check == NULL ? LZMA_CHECK_NONE
: coder->next.get_check(coder->next.coder);
}
static lzma_ret
auto_decoder_memconfig(lzma_coder *coder, uint64_t *memusage,
uint64_t *old_memlimit, uint64_t new_memlimit)
{
lzma_ret ret;
if (coder->next.memconfig != NULL) {
ret = coder->next.memconfig(coder->next.coder,
memusage, old_memlimit, new_memlimit);
assert(*old_memlimit == coder->memlimit);
} else {
// No coder is configured yet. Use the base value as
// the current memory usage.
*memusage = LZMA_MEMUSAGE_BASE;
*old_memlimit = coder->memlimit;
ret = LZMA_OK;
}
if (ret == LZMA_OK && new_memlimit != 0)
coder->memlimit = new_memlimit;
return ret;
}
static lzma_ret
auto_decoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
uint64_t memlimit, uint32_t flags)
{
lzma_next_coder_init(&auto_decoder_init, next, allocator);
if (memlimit == 0)
return LZMA_PROG_ERROR;
if (flags & ~LZMA_SUPPORTED_FLAGS)
return LZMA_OPTIONS_ERROR;
if (next->coder == NULL) {
next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
if (next->coder == NULL)
return LZMA_MEM_ERROR;
next->code = &auto_decode;
next->end = &auto_decoder_end;
next->get_check = &auto_decoder_get_check;
next->memconfig = &auto_decoder_memconfig;
next->coder->next = LZMA_NEXT_CODER_INIT;
}
next->coder->memlimit = memlimit;
next->coder->flags = flags;
next->coder->sequence = SEQ_INIT;
return LZMA_OK;
}
extern LZMA_API(lzma_ret)
lzma_auto_decoder(lzma_stream *strm, uint64_t memlimit, uint32_t flags)
{
lzma_next_strm_init(auto_decoder_init, strm, memlimit, flags);
strm->internal->supported_actions[LZMA_RUN] = true;
strm->internal->supported_actions[LZMA_FINISH] = true;
return LZMA_OK;
}
|
