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1 ///////////////////////////////////////////////////////////////////////////////
2 //
3 /// \file       alone_decoder.c
4 /// \brief      Decoder for LZMA_Alone files
5 //
6 //  Author:     Lasse Collin
7 //
8 //  This file has been put into the public domain.
9 //  You can do whatever you want with this file.
10 //
11 ///////////////////////////////////////////////////////////////////////////////
12
13 #include "common.h"
14 #include "lzma_encoder.h"
15
16
17 #define ALONE_HEADER_SIZE (1 + 4 + 8)
18
19
20 typedef struct {
21         lzma_next_coder next;
22
23         enum {
24                 SEQ_HEADER,
25                 SEQ_CODE,
26         } sequence;
27
28         size_t header_pos;
29         uint8_t header[ALONE_HEADER_SIZE];
30 } lzma_alone_coder;
31
32
33 static lzma_ret
34 alone_encode(void *coder_ptr,
35                 const lzma_allocator *allocator lzma_attribute((__unused__)),
36                 const uint8_t *restrict in, size_t *restrict in_pos,
37                 size_t in_size, uint8_t *restrict out,
38                 size_t *restrict out_pos, size_t out_size,
39                 lzma_action action)
40 {
41         lzma_alone_coder *coder = coder_ptr;
42
43         while (*out_pos < out_size)
44         switch (coder->sequence) {
45         case SEQ_HEADER:
46                 lzma_bufcpy(coder->header, &coder->header_pos,
47                                 ALONE_HEADER_SIZE,
48                                 out, out_pos, out_size);
49                 if (coder->header_pos < ALONE_HEADER_SIZE)
50                         return LZMA_OK;
51
52                 coder->sequence = SEQ_CODE;
53                 break;
54
55         case SEQ_CODE:
56                 return coder->next.code(coder->next.coder,
57                                 allocator, in, in_pos, in_size,
58                                 out, out_pos, out_size, action);
59
60         default:
61                 assert(0);
62                 return LZMA_PROG_ERROR;
63         }
64
65         return LZMA_OK;
66 }
67
68
69 static void
70 alone_encoder_end(void *coder_ptr, const lzma_allocator *allocator)
71 {
72         lzma_alone_coder *coder = coder_ptr;
73         lzma_next_end(&coder->next, allocator);
74         lzma_free(coder, allocator);
75         return;
76 }
77
78
79 // At least for now, this is not used by any internal function.
80 static lzma_ret
81 alone_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
82                 const lzma_options_lzma *options)
83 {
84         lzma_next_coder_init(&alone_encoder_init, next, allocator);
85
86         lzma_alone_coder *coder = next->coder;
87
88         if (coder == NULL) {
89                 coder = lzma_alloc(sizeof(lzma_alone_coder), allocator);
90                 if (coder == NULL)
91                         return LZMA_MEM_ERROR;
92
93                 next->coder = coder;
94                 next->code = &alone_encode;
95                 next->end = &alone_encoder_end;
96                 coder->next = LZMA_NEXT_CODER_INIT;
97         }
98
99         // Basic initializations
100         coder->sequence = SEQ_HEADER;
101         coder->header_pos = 0;
102
103         // Encode the header:
104         // - Properties (1 byte)
105         if (lzma_lzma_lclppb_encode(options, coder->header))
106                 return LZMA_OPTIONS_ERROR;
107
108         // - Dictionary size (4 bytes)
109         if (options->dict_size < LZMA_DICT_SIZE_MIN)
110                 return LZMA_OPTIONS_ERROR;
111
112         // Round up to the next 2^n or 2^n + 2^(n - 1) depending on which
113         // one is the next unless it is UINT32_MAX. While the header would
114         // allow any 32-bit integer, we do this to keep the decoder of liblzma
115         // accepting the resulting files.
116         uint32_t d = options->dict_size - 1;
117         d |= d >> 2;
118         d |= d >> 3;
119         d |= d >> 4;
120         d |= d >> 8;
121         d |= d >> 16;
122         if (d != UINT32_MAX)
123                 ++d;
124
125         unaligned_write32le(coder->header + 1, d);
126
127         // - Uncompressed size (always unknown and using EOPM)
128         memset(coder->header + 1 + 4, 0xFF, 8);
129
130         // Initialize the LZMA encoder.
131         const lzma_filter_info filters[2] = {
132                 {
133                         .init = &lzma_lzma_encoder_init,
134                         .options = (void *)(options),
135                 }, {
136                         .init = NULL,
137                 }
138         };
139
140         return lzma_next_filter_init(&coder->next, allocator, filters);
141 }
142
143
144 /*
145 extern lzma_ret
146 lzma_alone_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
147                 const lzma_options_alone *options)
148 {
149         lzma_next_coder_init(&alone_encoder_init, next, allocator, options);
150 }
151 */
152
153
154 extern LZMA_API(lzma_ret)
155 lzma_alone_encoder(lzma_stream *strm, const lzma_options_lzma *options)
156 {
157         lzma_next_strm_init(alone_encoder_init, strm, options);
158
159         strm->internal->supported_actions[LZMA_RUN] = true;
160         strm->internal->supported_actions[LZMA_FINISH] = true;
161
162         return LZMA_OK;
163 }