1 ///////////////////////////////////////////////////////////////////////////////
2 //
3 /// \file lzma2_decoder.c
4 /// \brief LZMA2 decoder
5 ///
6 // Authors: Igor Pavlov
7 // Lasse Collin
8 //
9 // This file has been put into the public domain.
10 // You can do whatever you want with this file.
11 //
12 ///////////////////////////////////////////////////////////////////////////////
13
14 #include "lzma2_decoder.h"
15 #include "lz_decoder.h"
16 #include "lzma_decoder.h"
17
18
19 struct lzma_coder_s {
20 enum sequence {
21 SEQ_CONTROL,
22 SEQ_UNCOMPRESSED_1,
23 SEQ_UNCOMPRESSED_2,
24 SEQ_COMPRESSED_0,
25 SEQ_COMPRESSED_1,
26 SEQ_PROPERTIES,
27 SEQ_LZMA,
28 SEQ_COPY,
29 } sequence;
30
31 /// Sequence after the size fields have been decoded.
32 enum sequence next_sequence;
33
34 /// LZMA decoder
35 lzma_lz_decoder lzma;
36
37 /// Uncompressed size of LZMA chunk
38 size_t uncompressed_size;
39
40 /// Compressed size of the chunk (naturally equals to uncompressed
41 /// size of uncompressed chunk)
42 size_t compressed_size;
43
44 /// True if properties are needed. This is false before the
45 /// first LZMA chunk.
46 bool need_properties;
47
48 /// True if dictionary reset is needed. This is false before the
49 /// first chunk (LZMA or uncompressed).
50 bool need_dictionary_reset;
51
52 lzma_options_lzma options;
53 };
54
55
56 static lzma_ret
lzma2_decode(lzma_coder * restrict coder,lzma_dict * restrict dict,const uint8_t * restrict in,size_t * restrict in_pos,size_t in_size)57 lzma2_decode(lzma_coder *restrict coder, lzma_dict *restrict dict,
58 const uint8_t *restrict in, size_t *restrict in_pos,
59 size_t in_size)
60 {
61 // With SEQ_LZMA it is possible that no new input is needed to do
62 // some progress. The rest of the sequences assume that there is
63 // at least one byte of input.
64 while (*in_pos < in_size || coder->sequence == SEQ_LZMA)
65 switch (coder->sequence) {
66 case SEQ_CONTROL: {
67 const uint32_t control = in[*in_pos];
68 ++*in_pos;
69
70 // End marker
71 if (control == 0x00)
72 return LZMA_STREAM_END;
73
74 if (control >= 0xE0 || control == 1) {
75 // Dictionary reset implies that next LZMA chunk has
76 // to set new properties.
77 coder->need_properties = true;
78 coder->need_dictionary_reset = true;
79 } else if (coder->need_dictionary_reset) {
80 return LZMA_DATA_ERROR;
81 }
82
83 if (control >= 0x80) {
84 // LZMA chunk. The highest five bits of the
85 // uncompressed size are taken from the control byte.
86 coder->uncompressed_size = (control & 0x1F) << 16;
87 coder->sequence = SEQ_UNCOMPRESSED_1;
88
89 // See if there are new properties or if we need to
90 // reset the state.
91 if (control >= 0xC0) {
92 // When there are new properties, state reset
93 // is done at SEQ_PROPERTIES.
94 coder->need_properties = false;
95 coder->next_sequence = SEQ_PROPERTIES;
96
97 } else if (coder->need_properties) {
98 return LZMA_DATA_ERROR;
99
100 } else {
101 coder->next_sequence = SEQ_LZMA;
102
103 // If only state reset is wanted with old
104 // properties, do the resetting here for
105 // simplicity.
106 if (control >= 0xA0)
107 coder->lzma.reset(coder->lzma.coder,
108 &coder->options);
109 }
110 } else {
111 // Invalid control values
112 if (control > 2)
113 return LZMA_DATA_ERROR;
114
115 // It's uncompressed chunk
116 coder->sequence = SEQ_COMPRESSED_0;
117 coder->next_sequence = SEQ_COPY;
118 }
119
120 if (coder->need_dictionary_reset) {
121 // Finish the dictionary reset and let the caller
122 // flush the dictionary to the actual output buffer.
123 coder->need_dictionary_reset = false;
124 dict_reset(dict);
125 return LZMA_OK;
126 }
127
128 break;
129 }
130
131 case SEQ_UNCOMPRESSED_1:
132 coder->uncompressed_size += (uint32_t)(in[(*in_pos)++]) << 8;
133 coder->sequence = SEQ_UNCOMPRESSED_2;
134 break;
135
136 case SEQ_UNCOMPRESSED_2:
137 coder->uncompressed_size += in[(*in_pos)++] + 1;
138 coder->sequence = SEQ_COMPRESSED_0;
139 coder->lzma.set_uncompressed(coder->lzma.coder,
140 coder->uncompressed_size);
141 break;
142
143 case SEQ_COMPRESSED_0:
144 coder->compressed_size = (uint32_t)(in[(*in_pos)++]) << 8;
145 coder->sequence = SEQ_COMPRESSED_1;
146 break;
147
148 case SEQ_COMPRESSED_1:
149 coder->compressed_size += in[(*in_pos)++] + 1;
150 coder->sequence = coder->next_sequence;
151 break;
152
153 case SEQ_PROPERTIES:
154 if (lzma_lzma_lclppb_decode(&coder->options, in[(*in_pos)++]))
155 return LZMA_DATA_ERROR;
156
157 coder->lzma.reset(coder->lzma.coder, &coder->options);
158
159 coder->sequence = SEQ_LZMA;
160 break;
161
162 case SEQ_LZMA: {
163 // Store the start offset so that we can update
164 // coder->compressed_size later.
165 const size_t in_start = *in_pos;
166
167 // Decode from in[] to *dict.
168 const lzma_ret ret = coder->lzma.code(coder->lzma.coder,
169 dict, in, in_pos, in_size);
170
171 // Validate and update coder->compressed_size.
172 const size_t in_used = *in_pos - in_start;
173 if (in_used > coder->compressed_size)
174 return LZMA_DATA_ERROR;
175
176 coder->compressed_size -= in_used;
177
178 // Return if we didn't finish the chunk, or an error occurred.
179 if (ret != LZMA_STREAM_END)
180 return ret;
181
182 // The LZMA decoder must have consumed the whole chunk now.
183 // We don't need to worry about uncompressed size since it
184 // is checked by the LZMA decoder.
185 if (coder->compressed_size != 0)
186 return LZMA_DATA_ERROR;
187
188 coder->sequence = SEQ_CONTROL;
189 break;
190 }
191
192 case SEQ_COPY: {
193 // Copy from input to the dictionary as is.
194 dict_write(dict, in, in_pos, in_size, &coder->compressed_size);
195 if (coder->compressed_size != 0)
196 return LZMA_OK;
197
198 coder->sequence = SEQ_CONTROL;
199 break;
200 }
201
202 default:
203 assert(0);
204 return LZMA_PROG_ERROR;
205 }
206
207 return LZMA_OK;
208 }
209
210
211 static void
lzma2_decoder_end(lzma_coder * coder,const lzma_allocator * allocator)212 lzma2_decoder_end(lzma_coder *coder, const lzma_allocator *allocator)
213 {
214 assert(coder->lzma.end == NULL);
215 lzma_free(coder->lzma.coder, allocator);
216
217 lzma_free(coder, allocator);
218
219 return;
220 }
221
222
223 static lzma_ret
lzma2_decoder_init(lzma_lz_decoder * lz,const lzma_allocator * allocator,const void * opt,lzma_lz_options * lz_options)224 lzma2_decoder_init(lzma_lz_decoder *lz, const lzma_allocator *allocator,
225 const void *opt, lzma_lz_options *lz_options)
226 {
227 if (lz->coder == NULL) {
228 lz->coder = lzma_alloc(sizeof(lzma_coder), allocator);
229 if (lz->coder == NULL)
230 return LZMA_MEM_ERROR;
231
232 lz->code = &lzma2_decode;
233 lz->end = &lzma2_decoder_end;
234
235 lz->coder->lzma = LZMA_LZ_DECODER_INIT;
236 }
237
238 const lzma_options_lzma *options = opt;
239
240 lz->coder->sequence = SEQ_CONTROL;
241 lz->coder->need_properties = true;
242 lz->coder->need_dictionary_reset = options->preset_dict == NULL
243 || options->preset_dict_size == 0;
244
245 return lzma_lzma_decoder_create(&lz->coder->lzma,
246 allocator, options, lz_options);
247 }
248
249
250 extern lzma_ret
lzma_lzma2_decoder_init(lzma_next_coder * next,const lzma_allocator * allocator,const lzma_filter_info * filters)251 lzma_lzma2_decoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
252 const lzma_filter_info *filters)
253 {
254 // LZMA2 can only be the last filter in the chain. This is enforced
255 // by the raw_decoder initialization.
256 assert(filters[1].init == NULL);
257
258 return lzma_lz_decoder_init(next, allocator, filters,
259 &lzma2_decoder_init);
260 }
261
262
263 extern uint64_t
lzma_lzma2_decoder_memusage(const void * options)264 lzma_lzma2_decoder_memusage(const void *options)
265 {
266 return sizeof(lzma_coder)
267 + lzma_lzma_decoder_memusage_nocheck(options);
268 }
269
270
271 extern lzma_ret
lzma_lzma2_props_decode(void ** options,const lzma_allocator * allocator,const uint8_t * props,size_t props_size)272 lzma_lzma2_props_decode(void **options, const lzma_allocator *allocator,
273 const uint8_t *props, size_t props_size)
274 {
275 if (props_size != 1)
276 return LZMA_OPTIONS_ERROR;
277
278 // Check that reserved bits are unset.
279 if (props[0] & 0xC0)
280 return LZMA_OPTIONS_ERROR;
281
282 // Decode the dictionary size.
283 if (props[0] > 40)
284 return LZMA_OPTIONS_ERROR;
285
286 lzma_options_lzma *opt = lzma_alloc(
287 sizeof(lzma_options_lzma), allocator);
288 if (opt == NULL)
289 return LZMA_MEM_ERROR;
290
291 if (props[0] == 40) {
292 opt->dict_size = UINT32_MAX;
293 } else {
294 opt->dict_size = 2 | (props[0] & 1);
295 opt->dict_size <<= props[0] / 2 + 11;
296 }
297
298 opt->preset_dict = NULL;
299 opt->preset_dict_size = 0;
300
301 *options = opt;
302
303 return LZMA_OK;
304 }
305