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 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 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 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 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) 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_SYNC_FLUSH] = true; 221 strm->internal->supported_actions[LZMA_FINISH] = true; 222 223 return LZMA_OK; 224 } 225