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 // Call lzma_check_update() only if input was consumed. This 81 // avoids null pointer + 0 (undefined behavior) when in == 0. 82 if (in_used > 0) 83 lzma_check_update(&coder->check, coder->block->check, 84 in + in_start, in_used); 85 86 if (ret != LZMA_STREAM_END || action == LZMA_SYNC_FLUSH) 87 return ret; 88 89 assert(*in_pos == in_size); 90 assert(action == LZMA_FINISH); 91 92 // Copy the values into coder->block. The caller 93 // may use this information to construct Index. 94 coder->block->compressed_size = coder->compressed_size; 95 coder->block->uncompressed_size = coder->uncompressed_size; 96 97 coder->sequence = SEQ_PADDING; 98 } 99 100 // Fall through 101 102 case SEQ_PADDING: 103 // Pad Compressed Data to a multiple of four bytes. We can 104 // use coder->compressed_size for this since we don't need 105 // it for anything else anymore. 106 while (coder->compressed_size & 3) { 107 if (*out_pos >= out_size) 108 return LZMA_OK; 109 110 out[*out_pos] = 0x00; 111 ++*out_pos; 112 ++coder->compressed_size; 113 } 114 115 if (coder->block->check == LZMA_CHECK_NONE) 116 return LZMA_STREAM_END; 117 118 lzma_check_finish(&coder->check, coder->block->check); 119 120 coder->sequence = SEQ_CHECK; 121 122 // Fall through 123 124 case SEQ_CHECK: { 125 const size_t check_size = lzma_check_size(coder->block->check); 126 lzma_bufcpy(coder->check.buffer.u8, &coder->pos, check_size, 127 out, out_pos, out_size); 128 if (coder->pos < check_size) 129 return LZMA_OK; 130 131 memcpy(coder->block->raw_check, coder->check.buffer.u8, 132 check_size); 133 return LZMA_STREAM_END; 134 } 135 } 136 137 return LZMA_PROG_ERROR; 138 } 139 140 141 static void 142 block_encoder_end(void *coder_ptr, const lzma_allocator *allocator) 143 { 144 lzma_block_coder *coder = coder_ptr; 145 lzma_next_end(&coder->next, allocator); 146 lzma_free(coder, allocator); 147 return; 148 } 149 150 151 static lzma_ret 152 block_encoder_update(void *coder_ptr, const lzma_allocator *allocator, 153 const lzma_filter *filters lzma_attribute((__unused__)), 154 const lzma_filter *reversed_filters) 155 { 156 lzma_block_coder *coder = coder_ptr; 157 158 if (coder->sequence != SEQ_CODE) 159 return LZMA_PROG_ERROR; 160 161 return lzma_next_filter_update( 162 &coder->next, allocator, reversed_filters); 163 } 164 165 166 extern lzma_ret 167 lzma_block_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator, 168 lzma_block *block) 169 { 170 lzma_next_coder_init(&lzma_block_encoder_init, next, allocator); 171 172 if (block == NULL) 173 return LZMA_PROG_ERROR; 174 175 // The contents of the structure may depend on the version so 176 // check the version first. 177 if (block->version > 1) 178 return LZMA_OPTIONS_ERROR; 179 180 // If the Check ID is not supported, we cannot calculate the check and 181 // thus not create a proper Block. 182 if ((unsigned int)(block->check) > LZMA_CHECK_ID_MAX) 183 return LZMA_PROG_ERROR; 184 185 if (!lzma_check_is_supported(block->check)) 186 return LZMA_UNSUPPORTED_CHECK; 187 188 // Allocate and initialize *next->coder if needed. 189 lzma_block_coder *coder = next->coder; 190 if (coder == NULL) { 191 coder = lzma_alloc(sizeof(lzma_block_coder), allocator); 192 if (coder == NULL) 193 return LZMA_MEM_ERROR; 194 195 next->coder = coder; 196 next->code = &block_encode; 197 next->end = &block_encoder_end; 198 next->update = &block_encoder_update; 199 coder->next = LZMA_NEXT_CODER_INIT; 200 } 201 202 // Basic initializations 203 coder->sequence = SEQ_CODE; 204 coder->block = block; 205 coder->compressed_size = 0; 206 coder->uncompressed_size = 0; 207 coder->pos = 0; 208 209 // Initialize the check 210 lzma_check_init(&coder->check, block->check); 211 212 // Initialize the requested filters. 213 return lzma_raw_encoder_init(&coder->next, allocator, block->filters); 214 } 215 216 217 extern LZMA_API(lzma_ret) 218 lzma_block_encoder(lzma_stream *strm, lzma_block *block) 219 { 220 lzma_next_strm_init(lzma_block_encoder_init, strm, block); 221 222 strm->internal->supported_actions[LZMA_RUN] = true; 223 strm->internal->supported_actions[LZMA_SYNC_FLUSH] = true; 224 strm->internal->supported_actions[LZMA_FINISH] = true; 225 226 return LZMA_OK; 227 } 228