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 typedef struct {
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 } lzma_lzma2_coder;
54
55
56 static lzma_ret
57 lzma2_decode(void *coder_ptr, lzma_dict *restrict dict,
58 const uint8_t *restrict in, size_t *restrict in_pos,
59 size_t in_size)
60 {
61 lzma_lzma2_coder *restrict coder = coder_ptr;
62
63 // With SEQ_LZMA it is possible that no new input is needed to do
64 // some progress. The rest of the sequences assume that there is
65 // at least one byte of input.
66 while (*in_pos < in_size || coder->sequence == SEQ_LZMA)
67 switch (coder->sequence) {
68 case SEQ_CONTROL: {
69 const uint32_t control = in[*in_pos];
70 ++*in_pos;
71
72 // End marker
73 if (control == 0x00)
74 return LZMA_STREAM_END;
75
76 if (control >= 0xE0 || control == 1) {
77 // Dictionary reset implies that next LZMA chunk has
78 // to set new properties.
79 coder->need_properties = true;
80 coder->need_dictionary_reset = true;
81 } else if (coder->need_dictionary_reset) {
82 return LZMA_DATA_ERROR;
83 }
84
85 if (control >= 0x80) {
86 // LZMA chunk. The highest five bits of the
87 // uncompressed size are taken from the control byte.
88 coder->uncompressed_size = (control & 0x1F) << 16;
89 coder->sequence = SEQ_UNCOMPRESSED_1;
90
91 // See if there are new properties or if we need to
92 // reset the state.
93 if (control >= 0xC0) {
94 // When there are new properties, state reset
95 // is done at SEQ_PROPERTIES.
96 coder->need_properties = false;
97 coder->next_sequence = SEQ_PROPERTIES;
98
99 } else if (coder->need_properties) {
100 return LZMA_DATA_ERROR;
101
102 } else {
103 coder->next_sequence = SEQ_LZMA;
104
105 // If only state reset is wanted with old
106 // properties, do the resetting here for
107 // simplicity.
108 if (control >= 0xA0)
109 coder->lzma.reset(coder->lzma.coder,
110 &coder->options);
111 }
112 } else {
113 // Invalid control values
114 if (control > 2)
115 return LZMA_DATA_ERROR;
116
117 // It's uncompressed chunk
118 coder->sequence = SEQ_COMPRESSED_0;
119 coder->next_sequence = SEQ_COPY;
120 }
121
122 if (coder->need_dictionary_reset) {
123 // Finish the dictionary reset and let the caller
124 // flush the dictionary to the actual output buffer.
125 coder->need_dictionary_reset = false;
126 dict_reset(dict);
127 return LZMA_OK;
128 }
129
130 break;
131 }
132
133 case SEQ_UNCOMPRESSED_1:
134 coder->uncompressed_size += (uint32_t)(in[(*in_pos)++]) << 8;
135 coder->sequence = SEQ_UNCOMPRESSED_2;
136 break;
137
138 case SEQ_UNCOMPRESSED_2:
139 coder->uncompressed_size += in[(*in_pos)++] + 1U;
140 coder->sequence = SEQ_COMPRESSED_0;
141 coder->lzma.set_uncompressed(coder->lzma.coder,
142 coder->uncompressed_size, false);
143 break;
144
145 case SEQ_COMPRESSED_0:
146 coder->compressed_size = (uint32_t)(in[(*in_pos)++]) << 8;
147 coder->sequence = SEQ_COMPRESSED_1;
148 break;
149
150 case SEQ_COMPRESSED_1:
151 coder->compressed_size += in[(*in_pos)++] + 1U;
152 coder->sequence = coder->next_sequence;
153 break;
154
155 case SEQ_PROPERTIES:
156 if (lzma_lzma_lclppb_decode(&coder->options, in[(*in_pos)++]))
157 return LZMA_DATA_ERROR;
158
159 coder->lzma.reset(coder->lzma.coder, &coder->options);
160
161 coder->sequence = SEQ_LZMA;
162 break;
163
164 case SEQ_LZMA: {
165 // Store the start offset so that we can update
166 // coder->compressed_size later.
167 const size_t in_start = *in_pos;
168
169 // Decode from in[] to *dict.
170 const lzma_ret ret = coder->lzma.code(coder->lzma.coder,
171 dict, in, in_pos, in_size);
172
173 // Validate and update coder->compressed_size.
174 const size_t in_used = *in_pos - in_start;
175 if (in_used > coder->compressed_size)
176 return LZMA_DATA_ERROR;
177
178 coder->compressed_size -= in_used;
179
180 // Return if we didn't finish the chunk, or an error occurred.
181 if (ret != LZMA_STREAM_END)
182 return ret;
183
184 // The LZMA decoder must have consumed the whole chunk now.
185 // We don't need to worry about uncompressed size since it
186 // is checked by the LZMA decoder.
187 if (coder->compressed_size != 0)
188 return LZMA_DATA_ERROR;
189
190 coder->sequence = SEQ_CONTROL;
191 break;
192 }
193
194 case SEQ_COPY: {
195 // Copy from input to the dictionary as is.
196 dict_write(dict, in, in_pos, in_size, &coder->compressed_size);
197 if (coder->compressed_size != 0)
198 return LZMA_OK;
199
200 coder->sequence = SEQ_CONTROL;
201 break;
202 }
203
204 default:
205 assert(0);
206 return LZMA_PROG_ERROR;
207 }
208
209 return LZMA_OK;
210 }
211
212
213 static void
214 lzma2_decoder_end(void *coder_ptr, const lzma_allocator *allocator)
215 {
216 lzma_lzma2_coder *coder = coder_ptr;
217
218 assert(coder->lzma.end == NULL);
219 lzma_free(coder->lzma.coder, allocator);
220
221 lzma_free(coder, allocator);
222
223 return;
224 }
225
226
227 static lzma_ret
228 lzma2_decoder_init(lzma_lz_decoder *lz, const lzma_allocator *allocator,
229 lzma_vli id lzma_attribute((__unused__)), const void *opt,
230 lzma_lz_options *lz_options)
231 {
232 lzma_lzma2_coder *coder = lz->coder;
233 if (coder == NULL) {
234 coder = lzma_alloc(sizeof(lzma_lzma2_coder), allocator);
235 if (coder == NULL)
236 return LZMA_MEM_ERROR;
237
238 lz->coder = coder;
239 lz->code = &lzma2_decode;
240 lz->end = &lzma2_decoder_end;
241
242 coder->lzma = LZMA_LZ_DECODER_INIT;
243 }
244
245 const lzma_options_lzma *options = opt;
246
247 coder->sequence = SEQ_CONTROL;
248 coder->need_properties = true;
249 coder->need_dictionary_reset = options->preset_dict == NULL
250 || options->preset_dict_size == 0;
251
252 return lzma_lzma_decoder_create(&coder->lzma,
253 allocator, options, lz_options);
254 }
255
256
257 extern lzma_ret
258 lzma_lzma2_decoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
259 const lzma_filter_info *filters)
260 {
261 // LZMA2 can only be the last filter in the chain. This is enforced
262 // by the raw_decoder initialization.
263 assert(filters[1].init == NULL);
264
265 return lzma_lz_decoder_init(next, allocator, filters,
266 &lzma2_decoder_init);
267 }
268
269
270 extern uint64_t
271 lzma_lzma2_decoder_memusage(const void *options)
272 {
273 return sizeof(lzma_lzma2_coder)
274 + lzma_lzma_decoder_memusage_nocheck(options);
275 }
276
277
278 extern lzma_ret
279 lzma_lzma2_props_decode(void **options, const lzma_allocator *allocator,
280 const uint8_t *props, size_t props_size)
281 {
282 if (props_size != 1)
283 return LZMA_OPTIONS_ERROR;
284
285 // Check that reserved bits are unset.
286 if (props[0] & 0xC0)
287 return LZMA_OPTIONS_ERROR;
288
289 // Decode the dictionary size.
290 if (props[0] > 40)
291 return LZMA_OPTIONS_ERROR;
292
293 lzma_options_lzma *opt = lzma_alloc(
294 sizeof(lzma_options_lzma), allocator);
295 if (opt == NULL)
296 return LZMA_MEM_ERROR;
297
298 if (props[0] == 40) {
299 opt->dict_size = UINT32_MAX;
300 } else {
301 opt->dict_size = 2 | (props[0] & 1U);
302 opt->dict_size <<= props[0] / 2U + 11;
303 }
304
305 opt->preset_dict = NULL;
306 opt->preset_dict_size = 0;
307
308 *options = opt;
309
310 return LZMA_OK;
311 }