1 ///////////////////////////////////////////////////////////////////////////////
3 /// \file auto_decoder.c
4 /// \brief Autodetect between .xz Stream and .lzma (LZMA_Alone) formats
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 "stream_decoder.h"
14 #include "alone_decoder.h"
18 /// Stream decoder or LZMA_Alone decoder
33 auto_decode(lzma_coder *coder, const lzma_allocator *allocator,
34 const uint8_t *restrict in, size_t *restrict in_pos,
35 size_t in_size, uint8_t *restrict out,
36 size_t *restrict out_pos, size_t out_size, lzma_action action)
38 switch (coder->sequence) {
40 if (*in_pos >= in_size)
43 // Update the sequence now, because we want to continue from
44 // SEQ_CODE even if we return some LZMA_*_CHECK.
45 coder->sequence = SEQ_CODE;
47 // Detect the file format. For now this is simple, since if
48 // it doesn't start with 0xFD (the first magic byte of the
49 // new format), it has to be LZMA_Alone, or something that
50 // we don't support at all.
51 if (in[*in_pos] == 0xFD) {
52 return_if_error(lzma_stream_decoder_init(
53 &coder->next, allocator,
54 coder->memlimit, coder->flags));
56 return_if_error(lzma_alone_decoder_init(&coder->next,
57 allocator, coder->memlimit, true));
59 // If the application wants to know about missing
60 // integrity check or about the check in general, we
61 // need to handle it here, because LZMA_Alone decoder
62 // doesn't accept any flags.
63 if (coder->flags & LZMA_TELL_NO_CHECK)
66 if (coder->flags & LZMA_TELL_ANY_CHECK)
67 return LZMA_GET_CHECK;
73 const lzma_ret ret = coder->next.code(
74 coder->next.coder, allocator,
76 out, out_pos, out_size, action);
77 if (ret != LZMA_STREAM_END
78 || (coder->flags & LZMA_CONCATENATED) == 0)
81 coder->sequence = SEQ_FINISH;
87 // When LZMA_DECODE_CONCATENATED was used and we were decoding
88 // LZMA_Alone file, we need to check check that there is no
89 // trailing garbage and wait for LZMA_FINISH.
90 if (*in_pos < in_size)
91 return LZMA_DATA_ERROR;
93 return action == LZMA_FINISH ? LZMA_STREAM_END : LZMA_OK;
97 return LZMA_PROG_ERROR;
103 auto_decoder_end(lzma_coder *coder, const lzma_allocator *allocator)
105 lzma_next_end(&coder->next, allocator);
106 lzma_free(coder, allocator);
112 auto_decoder_get_check(const lzma_coder *coder)
114 // It is LZMA_Alone if get_check is NULL.
115 return coder->next.get_check == NULL ? LZMA_CHECK_NONE
116 : coder->next.get_check(coder->next.coder);
121 auto_decoder_memconfig(lzma_coder *coder, uint64_t *memusage,
122 uint64_t *old_memlimit, uint64_t new_memlimit)
126 if (coder->next.memconfig != NULL) {
127 ret = coder->next.memconfig(coder->next.coder,
128 memusage, old_memlimit, new_memlimit);
129 assert(*old_memlimit == coder->memlimit);
131 // No coder is configured yet. Use the base value as
132 // the current memory usage.
133 *memusage = LZMA_MEMUSAGE_BASE;
134 *old_memlimit = coder->memlimit;
138 if (ret == LZMA_OK && new_memlimit != 0)
139 coder->memlimit = new_memlimit;
146 auto_decoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
147 uint64_t memlimit, uint32_t flags)
149 lzma_next_coder_init(&auto_decoder_init, next, allocator);
152 return LZMA_PROG_ERROR;
154 if (flags & ~LZMA_SUPPORTED_FLAGS)
155 return LZMA_OPTIONS_ERROR;
157 if (next->coder == NULL) {
158 next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
159 if (next->coder == NULL)
160 return LZMA_MEM_ERROR;
162 next->code = &auto_decode;
163 next->end = &auto_decoder_end;
164 next->get_check = &auto_decoder_get_check;
165 next->memconfig = &auto_decoder_memconfig;
166 next->coder->next = LZMA_NEXT_CODER_INIT;
169 next->coder->memlimit = memlimit;
170 next->coder->flags = flags;
171 next->coder->sequence = SEQ_INIT;
177 extern LZMA_API(lzma_ret)
178 lzma_auto_decoder(lzma_stream *strm, uint64_t memlimit, uint32_t flags)
180 lzma_next_strm_init(auto_decoder_init, strm, memlimit, flags);
182 strm->internal->supported_actions[LZMA_RUN] = true;
183 strm->internal->supported_actions[LZMA_FINISH] = true;