contrib/xz/src/liblzma/common/stream_encoder.c

   1 ///////////////////////////////////////////////////////////////////////////////
   2 //
   3 /// \file       stream_encoder.c
   4 /// \brief      Encodes .xz Streams
   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 "index_encoder.h"
  15
  16
  17 struct lzma_coder_s {
  18         enum {
  19                 SEQ_STREAM_HEADER,
  20                 SEQ_BLOCK_INIT,
  21                 SEQ_BLOCK_HEADER,
  22                 SEQ_BLOCK_ENCODE,
  23                 SEQ_INDEX_ENCODE,
  24                 SEQ_STREAM_FOOTER,
  25         } sequence;
  26
  27         /// True if Block encoder has been initialized by
  28         /// stream_encoder_init() or stream_encoder_update()
  29         /// and thus doesn't need to be initialized in stream_encode().
  30         bool block_encoder_is_initialized;
  31
  32         /// Block
  33         lzma_next_coder block_encoder;
  34
  35         /// Options for the Block encoder
  36         lzma_block block_options;
  37
  38         /// The filter chain currently in use
  39         lzma_filter filters[LZMA_FILTERS_MAX + 1];
  40
  41         /// Index encoder. This is separate from Block encoder, because this
  42         /// doesn't take much memory, and when encoding multiple Streams
  43         /// with the same encoding options we avoid reallocating memory.
  44         lzma_next_coder index_encoder;
  45
  46         /// Index to hold sizes of the Blocks
  47         lzma_index *index;
  48
  49         /// Read position in buffer[]
  50         size_t buffer_pos;
  51
  52         /// Total number of bytes in buffer[]
  53         size_t buffer_size;
  54
  55         /// Buffer to hold Stream Header, Block Header, and Stream Footer.
  56         /// Block Header has biggest maximum size.
  57         uint8_t buffer[LZMA_BLOCK_HEADER_SIZE_MAX];
  58 };
  59
  60
  61 static lzma_ret
  62 block_encoder_init(lzma_coder *coder, const lzma_allocator *allocator)
  63 {
  64         // Prepare the Block options. Even though Block encoder doesn't need
  65         // compressed_size, uncompressed_size, and header_size to be
  66         // initialized, it is a good idea to do it here, because this way
  67         // we catch if someone gave us Filter ID that cannot be used in
  68         // Blocks/Streams.
  69         coder->block_options.compressed_size = LZMA_VLI_UNKNOWN;
  70         coder->block_options.uncompressed_size = LZMA_VLI_UNKNOWN;
  71
  72         return_if_error(lzma_block_header_size(&coder->block_options));
  73
  74         // Initialize the actual Block encoder.
  75         return lzma_block_encoder_init(&coder->block_encoder, allocator,
  76                         &coder->block_options);
  77 }
  78
  79
  80 static lzma_ret
  81 stream_encode(lzma_coder *coder, const lzma_allocator *allocator,
  82                 const uint8_t *restrict in, size_t *restrict in_pos,
  83                 size_t in_size, uint8_t *restrict out,
  84                 size_t *restrict out_pos, size_t out_size, lzma_action action)
  85 {
  86         // Main loop
  87         while (*out_pos < out_size)
  88         switch (coder->sequence) {
  89         case SEQ_STREAM_HEADER:
  90         case SEQ_BLOCK_HEADER:
  91         case SEQ_STREAM_FOOTER:
  92                 lzma_bufcpy(coder->buffer, &coder->buffer_pos,
  93                                 coder->buffer_size, out, out_pos, out_size);
  94                 if (coder->buffer_pos < coder->buffer_size)
  95                         return LZMA_OK;
  96
  97                 if (coder->sequence == SEQ_STREAM_FOOTER)
  98                         return LZMA_STREAM_END;
  99
 100                 coder->buffer_pos = 0;
 101                 ++coder->sequence;
 102                 break;
 103
 104         case SEQ_BLOCK_INIT: {
 105                 if (*in_pos == in_size) {
 106                         // If we are requested to flush or finish the current
 107                         // Block, return LZMA_STREAM_END immediately since
 108                         // there's nothing to do.
 109                         if (action != LZMA_FINISH)
 110                                 return action == LZMA_RUN
 111                                                 ? LZMA_OK : LZMA_STREAM_END;
 112
 113                         // The application had used LZMA_FULL_FLUSH to finish
 114                         // the previous Block, but now wants to finish without
 115                         // encoding new data, or it is simply creating an
 116                         // empty Stream with no Blocks.
 117                         //
 118                         // Initialize the Index encoder, and continue to
 119                         // actually encoding the Index.
 120                         return_if_error(lzma_index_encoder_init(
 121                                         &coder->index_encoder, allocator,
 122                                         coder->index));
 123                         coder->sequence = SEQ_INDEX_ENCODE;
 124                         break;
 125                 }
 126
 127                 // Initialize the Block encoder unless it was already
 128                 // initialized by stream_encoder_init() or
 129                 // stream_encoder_update().
 130                 if (!coder->block_encoder_is_initialized)
 131                         return_if_error(block_encoder_init(coder, allocator));
 132
 133                 // Make it false so that we don't skip the initialization
 134                 // with the next Block.
 135                 coder->block_encoder_is_initialized = false;
 136
 137                 // Encode the Block Header. This shouldn't fail since we have
 138                 // already initialized the Block encoder.
 139                 if (lzma_block_header_encode(&coder->block_options,
 140                                 coder->buffer) != LZMA_OK)
 141                         return LZMA_PROG_ERROR;
 142
 143                 coder->buffer_size = coder->block_options.header_size;
 144                 coder->sequence = SEQ_BLOCK_HEADER;
 145                 break;
 146         }
 147
 148         case SEQ_BLOCK_ENCODE: {
 149                 static const lzma_action convert[LZMA_ACTION_MAX + 1] = {
 150                         LZMA_RUN,
 151                         LZMA_SYNC_FLUSH,
 152                         LZMA_FINISH,
 153                         LZMA_FINISH,
 154                         LZMA_FINISH,
 155                 };
 156
 157                 const lzma_ret ret = coder->block_encoder.code(
 158                                 coder->block_encoder.coder, allocator,
 159                                 in, in_pos, in_size,
 160                                 out, out_pos, out_size, convert[action]);
 161                 if (ret != LZMA_STREAM_END || action == LZMA_SYNC_FLUSH)
 162                         return ret;
 163
 164                 // Add a new Index Record.
 165                 const lzma_vli unpadded_size = lzma_block_unpadded_size(
 166                                 &coder->block_options);
 167                 assert(unpadded_size != 0);
 168                 return_if_error(lzma_index_append(coder->index, allocator,
 169                                 unpadded_size,
 170                                 coder->block_options.uncompressed_size));
 171
 172                 coder->sequence = SEQ_BLOCK_INIT;
 173                 break;
 174         }
 175
 176         case SEQ_INDEX_ENCODE: {
 177                 // Call the Index encoder. It doesn't take any input, so
 178                 // those pointers can be NULL.
 179                 const lzma_ret ret = coder->index_encoder.code(
 180                                 coder->index_encoder.coder, allocator,
 181                                 NULL, NULL, 0,
 182                                 out, out_pos, out_size, LZMA_RUN);
 183                 if (ret != LZMA_STREAM_END)
 184                         return ret;
 185
 186                 // Encode the Stream Footer into coder->buffer.
 187                 const lzma_stream_flags stream_flags = {
 188                         .version = 0,
 189                         .backward_size = lzma_index_size(coder->index),
 190                         .check = coder->block_options.check,
 191                 };
 192
 193                 if (lzma_stream_footer_encode(&stream_flags, coder->buffer)
 194                                 != LZMA_OK)
 195                         return LZMA_PROG_ERROR;
 196
 197                 coder->buffer_size = LZMA_STREAM_HEADER_SIZE;
 198                 coder->sequence = SEQ_STREAM_FOOTER;
 199                 break;
 200         }
 201
 202         default:
 203                 assert(0);
 204                 return LZMA_PROG_ERROR;
 205         }
 206
 207         return LZMA_OK;
 208 }
 209
 210
 211 static void
 212 stream_encoder_end(lzma_coder *coder, const lzma_allocator *allocator)
 213 {
 214         lzma_next_end(&coder->block_encoder, allocator);
 215         lzma_next_end(&coder->index_encoder, allocator);
 216         lzma_index_end(coder->index, allocator);
 217
 218         for (size_t i = 0; coder->filters[i].id != LZMA_VLI_UNKNOWN; ++i)
 219                 lzma_free(coder->filters[i].options, allocator);
 220
 221         lzma_free(coder, allocator);
 222         return;
 223 }
 224
 225
 226 static lzma_ret
 227 stream_encoder_update(lzma_coder *coder, const lzma_allocator *allocator,
 228                 const lzma_filter *filters,
 229                 const lzma_filter *reversed_filters)
 230 {
 231         if (coder->sequence <= SEQ_BLOCK_INIT) {
 232                 // There is no incomplete Block waiting to be finished,
 233                 // thus we can change the whole filter chain. Start by
 234                 // trying to initialize the Block encoder with the new
 235                 // chain. This way we detect if the chain is valid.
 236                 coder->block_encoder_is_initialized = false;
 237                 coder->block_options.filters = (lzma_filter *)(filters);
 238                 const lzma_ret ret = block_encoder_init(coder, allocator);
 239                 coder->block_options.filters = coder->filters;
 240                 if (ret != LZMA_OK)
 241                         return ret;
 242
 243                 coder->block_encoder_is_initialized = true;
 244
 245         } else if (coder->sequence <= SEQ_BLOCK_ENCODE) {
 246                 // We are in the middle of a Block. Try to update only
 247                 // the filter-specific options.
 248                 return_if_error(coder->block_encoder.update(
 249                                 coder->block_encoder.coder, allocator,
 250                                 filters, reversed_filters));
 251         } else {
 252                 // Trying to update the filter chain when we are already
 253                 // encoding Index or Stream Footer.
 254                 return LZMA_PROG_ERROR;
 255         }
 256
 257         // Free the copy of the old chain and make a copy of the new chain.
 258         for (size_t i = 0; coder->filters[i].id != LZMA_VLI_UNKNOWN; ++i)
 259                 lzma_free(coder->filters[i].options, allocator);
 260
 261         return lzma_filters_copy(filters, coder->filters, allocator);
 262 }
 263
 264
 265 static lzma_ret
 266 stream_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 267                 const lzma_filter *filters, lzma_check check)
 268 {
 269         lzma_next_coder_init(&stream_encoder_init, next, allocator);
 270
 271         if (filters == NULL)
 272                 return LZMA_PROG_ERROR;
 273
 274         if (next->coder == NULL) {
 275                 next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
 276                 if (next->coder == NULL)
 277                         return LZMA_MEM_ERROR;
 278
 279                 next->code = &stream_encode;
 280                 next->end = &stream_encoder_end;
 281                 next->update = &stream_encoder_update;
 282
 283                 next->coder->filters[0].id = LZMA_VLI_UNKNOWN;
 284                 next->coder->block_encoder = LZMA_NEXT_CODER_INIT;
 285                 next->coder->index_encoder = LZMA_NEXT_CODER_INIT;
 286                 next->coder->index = NULL;
 287         }
 288
 289         // Basic initializations
 290         next->coder->sequence = SEQ_STREAM_HEADER;
 291         next->coder->block_options.version = 0;
 292         next->coder->block_options.check = check;
 293
 294         // Initialize the Index
 295         lzma_index_end(next->coder->index, allocator);
 296         next->coder->index = lzma_index_init(allocator);
 297         if (next->coder->index == NULL)
 298                 return LZMA_MEM_ERROR;
 299
 300         // Encode the Stream Header
 301         lzma_stream_flags stream_flags = {
 302                 .version = 0,
 303                 .check = check,
 304         };
 305         return_if_error(lzma_stream_header_encode(
 306                         &stream_flags, next->coder->buffer));
 307
 308         next->coder->buffer_pos = 0;
 309         next->coder->buffer_size = LZMA_STREAM_HEADER_SIZE;
 310
 311         // Initialize the Block encoder. This way we detect unsupported
 312         // filter chains when initializing the Stream encoder instead of
 313         // giving an error after Stream Header has already written out.
 314         return stream_encoder_update(
 315                         next->coder, allocator, filters, NULL);
 316 }
 317
 318
 319 extern LZMA_API(lzma_ret)
 320 lzma_stream_encoder(lzma_stream *strm,
 321                 const lzma_filter *filters, lzma_check check)
 322 {
 323         lzma_next_strm_init(stream_encoder_init, strm, filters, check);
 324
 325         strm->internal->supported_actions[LZMA_RUN] = true;
 326         strm->internal->supported_actions[LZMA_SYNC_FLUSH] = true;
 327         strm->internal->supported_actions[LZMA_FULL_FLUSH] = true;
 328         strm->internal->supported_actions[LZMA_FULL_BARRIER] = true;
 329         strm->internal->supported_actions[LZMA_FINISH] = true;
 330
 331         return LZMA_OK;
 332 }