1 ///////////////////////////////////////////////////////////////////////////////
3 /// \file alone_decoder.c
4 /// \brief Decoder for LZMA_Alone files
6 // Author: Lasse Collin
8 // This file has been put into the public domain.
9 // You can do whatever you want with this file.
11 ///////////////////////////////////////////////////////////////////////////////
13 #include "alone_decoder.h"
14 #include "lzma_decoder.h"
15 #include "lz_decoder.h"
24 SEQ_UNCOMPRESSED_SIZE
,
29 /// Position in the header fields
32 /// Uncompressed size decoded from the header
33 lzma_vli uncompressed_size
;
35 /// Memory usage limit
38 /// Amount of memory actually needed (only an estimate)
41 /// Options decoded from the header needed to initialize
43 lzma_options_lzma options
;
48 alone_decode(lzma_coder
*coder
,
49 lzma_allocator
*allocator
lzma_attribute((__unused__
)),
50 const uint8_t *restrict in
, size_t *restrict in_pos
,
51 size_t in_size
, uint8_t *restrict out
,
52 size_t *restrict out_pos
, size_t out_size
,
55 while (*out_pos
< out_size
56 && (coder
->sequence
== SEQ_CODE
|| *in_pos
< in_size
))
57 switch (coder
->sequence
) {
59 if (lzma_lzma_lclppb_decode(&coder
->options
, in
[*in_pos
]))
60 return LZMA_FORMAT_ERROR
;
62 coder
->sequence
= SEQ_DICTIONARY_SIZE
;
66 case SEQ_DICTIONARY_SIZE
:
67 coder
->options
.dict_size
68 |= (size_t)(in
[*in_pos
]) << (coder
->pos
* 8);
70 if (++coder
->pos
== 4) {
71 if (coder
->options
.dict_size
!= UINT32_MAX
) {
72 // A hack to ditch tons of false positives:
73 // We allow only dictionary sizes that are
74 // 2^n or 2^n + 2^(n-1). LZMA_Alone created
75 // only files with 2^n, but accepts any
76 // dictionary size. If someone complains, this
77 // will be reconsidered.
78 uint32_t d
= coder
->options
.dict_size
- 1;
86 if (d
!= coder
->options
.dict_size
)
87 return LZMA_FORMAT_ERROR
;
91 coder
->sequence
= SEQ_UNCOMPRESSED_SIZE
;
97 case SEQ_UNCOMPRESSED_SIZE
:
98 coder
->uncompressed_size
99 |= (lzma_vli
)(in
[*in_pos
]) << (coder
->pos
* 8);
101 if (++coder
->pos
< 8)
104 // Another hack to ditch false positives: Assume that
105 // if the uncompressed size is known, it must be less
106 // than 256 GiB. Again, if someone complains, this
107 // will be reconsidered.
108 if (coder
->uncompressed_size
!= LZMA_VLI_UNKNOWN
109 && coder
->uncompressed_size
110 >= (LZMA_VLI_C(1) << 38))
111 return LZMA_FORMAT_ERROR
;
113 // Calculate the memory usage so that it is ready
114 // for SEQ_CODER_INIT.
115 coder
->memusage
= lzma_lzma_decoder_memusage(&coder
->options
)
116 + LZMA_MEMUSAGE_BASE
;
119 coder
->sequence
= SEQ_CODER_INIT
;
123 case SEQ_CODER_INIT
: {
124 if (coder
->memusage
> coder
->memlimit
)
125 return LZMA_MEMLIMIT_ERROR
;
127 lzma_filter_info filters
[2] = {
129 .init
= &lzma_lzma_decoder_init
,
130 .options
= &coder
->options
,
136 const lzma_ret ret
= lzma_next_filter_init(&coder
->next
,
141 // Use a hack to set the uncompressed size.
142 lzma_lz_decoder_uncompressed(coder
->next
.coder
,
143 coder
->uncompressed_size
);
145 coder
->sequence
= SEQ_CODE
;
150 return coder
->next
.code(coder
->next
.coder
,
151 allocator
, in
, in_pos
, in_size
,
152 out
, out_pos
, out_size
, action
);
156 return LZMA_PROG_ERROR
;
164 alone_decoder_end(lzma_coder
*coder
, lzma_allocator
*allocator
)
166 lzma_next_end(&coder
->next
, allocator
);
167 lzma_free(coder
, allocator
);
173 alone_decoder_memconfig(lzma_coder
*coder
, uint64_t *memusage
,
174 uint64_t *old_memlimit
, uint64_t new_memlimit
)
176 *memusage
= coder
->memusage
;
177 *old_memlimit
= coder
->memlimit
;
179 if (new_memlimit
!= 0) {
180 if (new_memlimit
< coder
->memusage
)
181 return LZMA_MEMLIMIT_ERROR
;
183 coder
->memlimit
= new_memlimit
;
191 lzma_alone_decoder_init(lzma_next_coder
*next
, lzma_allocator
*allocator
,
194 lzma_next_coder_init(&lzma_alone_decoder_init
, next
, allocator
);
197 return LZMA_PROG_ERROR
;
199 if (next
->coder
== NULL
) {
200 next
->coder
= lzma_alloc(sizeof(lzma_coder
), allocator
);
201 if (next
->coder
== NULL
)
202 return LZMA_MEM_ERROR
;
204 next
->code
= &alone_decode
;
205 next
->end
= &alone_decoder_end
;
206 next
->memconfig
= &alone_decoder_memconfig
;
207 next
->coder
->next
= LZMA_NEXT_CODER_INIT
;
210 next
->coder
->sequence
= SEQ_PROPERTIES
;
211 next
->coder
->pos
= 0;
212 next
->coder
->options
.dict_size
= 0;
213 next
->coder
->options
.preset_dict
= NULL
;
214 next
->coder
->options
.preset_dict_size
= 0;
215 next
->coder
->uncompressed_size
= 0;
216 next
->coder
->memlimit
= memlimit
;
217 next
->coder
->memusage
= LZMA_MEMUSAGE_BASE
;
223 extern LZMA_API(lzma_ret
)
224 lzma_alone_decoder(lzma_stream
*strm
, uint64_t memlimit
)
226 lzma_next_strm_init(lzma_alone_decoder_init
, strm
, memlimit
);
228 strm
->internal
->supported_actions
[LZMA_RUN
] = true;
229 strm
->internal
->supported_actions
[LZMA_FINISH
] = true;