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