1 ///////////////////////////////////////////////////////////////////////////////
3 /// \file block_encoder.c
4 /// \brief Encodes .xz Blocks
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 "block_encoder.h"
14 #include "filter_encoder.h"
19 /// The filters in the chain; initialized with lzma_raw_decoder_init().
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.
33 /// Compressed Size calculated while encoding
34 lzma_vli compressed_size;
36 /// Uncompressed Size calculated while encoding
37 lzma_vli uncompressed_size;
39 /// Position in the Check field
42 /// Check of the uncompressed data
43 lzma_check_state check;
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)
53 lzma_block_coder *coder = coder_ptr;
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;
59 switch (coder->sequence) {
61 const size_t in_start = *in_pos;
62 const size_t out_start = *out_pos;
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);
68 const size_t in_used = *in_pos - in_start;
69 const size_t out_used = *out_pos - out_start;
71 if (COMPRESSED_SIZE_MAX - coder->compressed_size < out_used)
72 return LZMA_DATA_ERROR;
74 coder->compressed_size += out_used;
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;
80 lzma_check_update(&coder->check, coder->block->check,
81 in + in_start, in_used);
83 if (ret != LZMA_STREAM_END || action == LZMA_SYNC_FLUSH)
86 assert(*in_pos == in_size);
87 assert(action == LZMA_FINISH);
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;
94 coder->sequence = 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)
107 out[*out_pos] = 0x00;
109 ++coder->compressed_size;
112 if (coder->block->check == LZMA_CHECK_NONE)
113 return LZMA_STREAM_END;
115 lzma_check_finish(&coder->check, coder->block->check);
117 coder->sequence = 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)
128 memcpy(coder->block->raw_check, coder->check.buffer.u8,
130 return LZMA_STREAM_END;
134 return LZMA_PROG_ERROR;
139 block_encoder_end(void *coder_ptr, const lzma_allocator *allocator)
141 lzma_block_coder *coder = coder_ptr;
142 lzma_next_end(&coder->next, allocator);
143 lzma_free(coder, allocator);
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)
153 lzma_block_coder *coder = coder_ptr;
155 if (coder->sequence != SEQ_CODE)
156 return LZMA_PROG_ERROR;
158 return lzma_next_filter_update(
159 &coder->next, allocator, reversed_filters);
164 lzma_block_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
167 lzma_next_coder_init(&lzma_block_encoder_init, next, allocator);
170 return LZMA_PROG_ERROR;
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;
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;
182 if (!lzma_check_is_supported(block->check))
183 return LZMA_UNSUPPORTED_CHECK;
185 // Allocate and initialize *next->coder if needed.
186 lzma_block_coder *coder = next->coder;
188 coder = lzma_alloc(sizeof(lzma_block_coder), allocator);
190 return LZMA_MEM_ERROR;
193 next->code = &block_encode;
194 next->end = &block_encoder_end;
195 next->update = &block_encoder_update;
196 coder->next = LZMA_NEXT_CODER_INIT;
199 // Basic initializations
200 coder->sequence = SEQ_CODE;
201 coder->block = block;
202 coder->compressed_size = 0;
203 coder->uncompressed_size = 0;
206 // Initialize the check
207 lzma_check_init(&coder->check, block->check);
209 // Initialize the requested filters.
210 return lzma_raw_encoder_init(&coder->next, allocator, block->filters);
214 extern LZMA_API(lzma_ret)
215 lzma_block_encoder(lzma_stream *strm, lzma_block *block)
217 lzma_next_strm_init(lzma_block_encoder_init, strm, block);
219 strm->internal->supported_actions[LZMA_RUN] = true;
220 strm->internal->supported_actions[LZMA_FINISH] = true;