1 ///////////////////////////////////////////////////////////////////////////////
2 //
3 /// \file block_encoder.c
4 /// \brief Encodes .xz Blocks
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 "block_encoder.h"
14 #include "filter_encoder.h"
15 #include "check.h"
16
17
18 typedef struct {
19 /// The filters in the chain; initialized with lzma_raw_decoder_init().
20 lzma_next_coder next;
21
22 /// Encoding options; we also write Unpadded Size, Compressed Size,
23 /// and Uncompressed Size back to this structure when the encoding
24 /// has been finished.
25 lzma_block *block;
26
27 enum {
28 SEQ_CODE,
29 SEQ_PADDING,
30 SEQ_CHECK,
31 } sequence;
32
33 /// Compressed Size calculated while encoding
34 lzma_vli compressed_size;
35
36 /// Uncompressed Size calculated while encoding
37 lzma_vli uncompressed_size;
38
39 /// Position in the Check field
40 size_t pos;
41
42 /// Check of the uncompressed data
43 lzma_check_state check;
44 } lzma_block_coder;
45
46
47 static lzma_ret
block_encode(void * coder_ptr,const lzma_allocator * allocator,const uint8_t * restrict in,size_t * restrict in_pos,size_t in_size,uint8_t * restrict out,size_t * restrict out_pos,size_t out_size,lzma_action action)48 block_encode(void *coder_ptr, const lzma_allocator *allocator,
49 const uint8_t *restrict in, size_t *restrict in_pos,
50 size_t in_size, uint8_t *restrict out,
51 size_t *restrict out_pos, size_t out_size, lzma_action action)
52 {
53 lzma_block_coder *coder = coder_ptr;
54
55 // Check that our amount of input stays in proper limits.
56 if (LZMA_VLI_MAX - coder->uncompressed_size < in_size - *in_pos)
57 return LZMA_DATA_ERROR;
58
59 switch (coder->sequence) {
60 case SEQ_CODE: {
61 const size_t in_start = *in_pos;
62 const size_t out_start = *out_pos;
63
64 const lzma_ret ret = coder->next.code(coder->next.coder,
65 allocator, in, in_pos, in_size,
66 out, out_pos, out_size, action);
67
68 const size_t in_used = *in_pos - in_start;
69 const size_t out_used = *out_pos - out_start;
70
71 if (COMPRESSED_SIZE_MAX - coder->compressed_size < out_used)
72 return LZMA_DATA_ERROR;
73
74 coder->compressed_size += out_used;
75
76 // No need to check for overflow because we have already
77 // checked it at the beginning of this function.
78 coder->uncompressed_size += in_used;
79
80 lzma_check_update(&coder->check, coder->block->check,
81 in + in_start, in_used);
82
83 if (ret != LZMA_STREAM_END || action == LZMA_SYNC_FLUSH)
84 return ret;
85
86 assert(*in_pos == in_size);
87 assert(action == LZMA_FINISH);
88
89 // Copy the values into coder->block. The caller
90 // may use this information to construct Index.
91 coder->block->compressed_size = coder->compressed_size;
92 coder->block->uncompressed_size = coder->uncompressed_size;
93
94 coder->sequence = SEQ_PADDING;
95 }
96
97 // Fall through
98
99 case SEQ_PADDING:
100 // Pad Compressed Data to a multiple of four bytes. We can
101 // use coder->compressed_size for this since we don't need
102 // it for anything else anymore.
103 while (coder->compressed_size & 3) {
104 if (*out_pos >= out_size)
105 return LZMA_OK;
106
107 out[*out_pos] = 0x00;
108 ++*out_pos;
109 ++coder->compressed_size;
110 }
111
112 if (coder->block->check == LZMA_CHECK_NONE)
113 return LZMA_STREAM_END;
114
115 lzma_check_finish(&coder->check, coder->block->check);
116
117 coder->sequence = SEQ_CHECK;
118
119 // Fall through
120
121 case SEQ_CHECK: {
122 const size_t check_size = lzma_check_size(coder->block->check);
123 lzma_bufcpy(coder->check.buffer.u8, &coder->pos, check_size,
124 out, out_pos, out_size);
125 if (coder->pos < check_size)
126 return LZMA_OK;
127
128 memcpy(coder->block->raw_check, coder->check.buffer.u8,
129 check_size);
130 return LZMA_STREAM_END;
131 }
132 }
133
134 return LZMA_PROG_ERROR;
135 }
136
137
138 static void
block_encoder_end(void * coder_ptr,const lzma_allocator * allocator)139 block_encoder_end(void *coder_ptr, const lzma_allocator *allocator)
140 {
141 lzma_block_coder *coder = coder_ptr;
142 lzma_next_end(&coder->next, allocator);
143 lzma_free(coder, allocator);
144 return;
145 }
146
147
148 static lzma_ret
block_encoder_update(void * coder_ptr,const lzma_allocator * allocator,const lzma_filter * filters lzma_attribute ((__unused__)),const lzma_filter * reversed_filters)149 block_encoder_update(void *coder_ptr, const lzma_allocator *allocator,
150 const lzma_filter *filters lzma_attribute((__unused__)),
151 const lzma_filter *reversed_filters)
152 {
153 lzma_block_coder *coder = coder_ptr;
154
155 if (coder->sequence != SEQ_CODE)
156 return LZMA_PROG_ERROR;
157
158 return lzma_next_filter_update(
159 &coder->next, allocator, reversed_filters);
160 }
161
162
163 extern lzma_ret
lzma_block_encoder_init(lzma_next_coder * next,const lzma_allocator * allocator,lzma_block * block)164 lzma_block_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
165 lzma_block *block)
166 {
167 lzma_next_coder_init(&lzma_block_encoder_init, next, allocator);
168
169 if (block == NULL)
170 return LZMA_PROG_ERROR;
171
172 // The contents of the structure may depend on the version so
173 // check the version first.
174 if (block->version > 1)
175 return LZMA_OPTIONS_ERROR;
176
177 // If the Check ID is not supported, we cannot calculate the check and
178 // thus not create a proper Block.
179 if ((unsigned int)(block->check) > LZMA_CHECK_ID_MAX)
180 return LZMA_PROG_ERROR;
181
182 if (!lzma_check_is_supported(block->check))
183 return LZMA_UNSUPPORTED_CHECK;
184
185 // Allocate and initialize *next->coder if needed.
186 lzma_block_coder *coder = next->coder;
187 if (coder == NULL) {
188 coder = lzma_alloc(sizeof(lzma_block_coder), allocator);
189 if (coder == NULL)
190 return LZMA_MEM_ERROR;
191
192 next->coder = coder;
193 next->code = &block_encode;
194 next->end = &block_encoder_end;
195 next->update = &block_encoder_update;
196 coder->next = LZMA_NEXT_CODER_INIT;
197 }
198
199 // Basic initializations
200 coder->sequence = SEQ_CODE;
201 coder->block = block;
202 coder->compressed_size = 0;
203 coder->uncompressed_size = 0;
204 coder->pos = 0;
205
206 // Initialize the check
207 lzma_check_init(&coder->check, block->check);
208
209 // Initialize the requested filters.
210 return lzma_raw_encoder_init(&coder->next, allocator, block->filters);
211 }
212
213
214 extern LZMA_API(lzma_ret)
lzma_block_encoder(lzma_stream * strm,lzma_block * block)215 lzma_block_encoder(lzma_stream *strm, lzma_block *block)
216 {
217 lzma_next_strm_init(lzma_block_encoder_init, strm, block);
218
219 strm->internal->supported_actions[LZMA_RUN] = true;
220 strm->internal->supported_actions[LZMA_FINISH] = true;
221
222 return LZMA_OK;
223 }
224