xz-utils (5.4.5)
1 /**
2 * \file lzma/index.h
3 * \brief Handling of .xz Index and related information
4 * \note Never include this file directly. Use <lzma.h> instead.
5 */
6
7 /*
8 * Author: Lasse Collin
9 *
10 * This file has been put into the public domain.
11 * You can do whatever you want with this file.
12 */
13
14 #ifndef LZMA_H_INTERNAL
15 # error Never include this file directly. Use <lzma.h> instead.
16 #endif
17
18
19 /**
20 * \brief Opaque data type to hold the Index(es) and other information
21 *
22 * lzma_index often holds just one .xz Index and possibly the Stream Flags
23 * of the same Stream and size of the Stream Padding field. However,
24 * multiple lzma_indexes can be concatenated with lzma_index_cat() and then
25 * there may be information about multiple Streams in the same lzma_index.
26 *
27 * Notes about thread safety: Only one thread may modify lzma_index at
28 * a time. All functions that take non-const pointer to lzma_index
29 * modify it. As long as no thread is modifying the lzma_index, getting
30 * information from the same lzma_index can be done from multiple threads
31 * at the same time with functions that take a const pointer to
32 * lzma_index or use lzma_index_iter. The same iterator must be used
33 * only by one thread at a time, of course, but there can be as many
34 * iterators for the same lzma_index as needed.
35 */
36 typedef struct lzma_index_s lzma_index;
37
38
39 /**
40 * \brief Iterator to get information about Blocks and Streams
41 */
42 typedef struct {
43 struct {
44 /**
45 * \brief Pointer to Stream Flags
46 *
47 * This is NULL if Stream Flags have not been set for
48 * this Stream with lzma_index_stream_flags().
49 */
50 const lzma_stream_flags *flags;
51
52 /** \private Reserved member. */
53 const void *reserved_ptr1;
54
55 /** \private Reserved member. */
56 const void *reserved_ptr2;
57
58 /** \private Reserved member. */
59 const void *reserved_ptr3;
60
61 /**
62 * \brief Stream number in the lzma_index
63 *
64 * The first Stream is 1.
65 */
66 lzma_vli number;
67
68 /**
69 * \brief Number of Blocks in the Stream
70 *
71 * If this is zero, the block structure below has
72 * undefined values.
73 */
74 lzma_vli block_count;
75
76 /**
77 * \brief Compressed start offset of this Stream
78 *
79 * The offset is relative to the beginning of the lzma_index
80 * (i.e. usually the beginning of the .xz file).
81 */
82 lzma_vli compressed_offset;
83
84 /**
85 * \brief Uncompressed start offset of this Stream
86 *
87 * The offset is relative to the beginning of the lzma_index
88 * (i.e. usually the beginning of the .xz file).
89 */
90 lzma_vli uncompressed_offset;
91
92 /**
93 * \brief Compressed size of this Stream
94 *
95 * This includes all headers except the possible
96 * Stream Padding after this Stream.
97 */
98 lzma_vli compressed_size;
99
100 /**
101 * \brief Uncompressed size of this Stream
102 */
103 lzma_vli uncompressed_size;
104
105 /**
106 * \brief Size of Stream Padding after this Stream
107 *
108 * If it hasn't been set with lzma_index_stream_padding(),
109 * this defaults to zero. Stream Padding is always
110 * a multiple of four bytes.
111 */
112 lzma_vli padding;
113
114
115 /** \private Reserved member. */
116 lzma_vli reserved_vli1;
117
118 /** \private Reserved member. */
119 lzma_vli reserved_vli2;
120
121 /** \private Reserved member. */
122 lzma_vli reserved_vli3;
123
124 /** \private Reserved member. */
125 lzma_vli reserved_vli4;
126 } stream;
127
128 struct {
129 /**
130 * \brief Block number in the file
131 *
132 * The first Block is 1.
133 */
134 lzma_vli number_in_file;
135
136 /**
137 * \brief Compressed start offset of this Block
138 *
139 * This offset is relative to the beginning of the
140 * lzma_index (i.e. usually the beginning of the .xz file).
141 * Normally this is where you should seek in the .xz file
142 * to start decompressing this Block.
143 */
144 lzma_vli compressed_file_offset;
145
146 /**
147 * \brief Uncompressed start offset of this Block
148 *
149 * This offset is relative to the beginning of the lzma_index
150 * (i.e. usually the beginning of the .xz file).
151 *
152 * When doing random-access reading, it is possible that
153 * the target offset is not exactly at Block boundary. One
154 * will need to compare the target offset against
155 * uncompressed_file_offset or uncompressed_stream_offset,
156 * and possibly decode and throw away some amount of data
157 * before reaching the target offset.
158 */
159 lzma_vli uncompressed_file_offset;
160
161 /**
162 * \brief Block number in this Stream
163 *
164 * The first Block is 1.
165 */
166 lzma_vli number_in_stream;
167
168 /**
169 * \brief Compressed start offset of this Block
170 *
171 * This offset is relative to the beginning of the Stream
172 * containing this Block.
173 */
174 lzma_vli compressed_stream_offset;
175
176 /**
177 * \brief Uncompressed start offset of this Block
178 *
179 * This offset is relative to the beginning of the Stream
180 * containing this Block.
181 */
182 lzma_vli uncompressed_stream_offset;
183
184 /**
185 * \brief Uncompressed size of this Block
186 *
187 * You should pass this to the Block decoder if you will
188 * decode this Block. It will allow the Block decoder to
189 * validate the uncompressed size.
190 */
191 lzma_vli uncompressed_size;
192
193 /**
194 * \brief Unpadded size of this Block
195 *
196 * You should pass this to the Block decoder if you will
197 * decode this Block. It will allow the Block decoder to
198 * validate the unpadded size.
199 */
200 lzma_vli unpadded_size;
201
202 /**
203 * \brief Total compressed size
204 *
205 * This includes all headers and padding in this Block.
206 * This is useful if you need to know how many bytes
207 * the Block decoder will actually read.
208 */
209 lzma_vli total_size;
210
211 /** \private Reserved member. */
212 lzma_vli reserved_vli1;
213
214 /** \private Reserved member. */
215 lzma_vli reserved_vli2;
216
217 /** \private Reserved member. */
218 lzma_vli reserved_vli3;
219
220 /** \private Reserved member. */
221 lzma_vli reserved_vli4;
222
223 /** \private Reserved member. */
224 const void *reserved_ptr1;
225
226 /** \private Reserved member. */
227 const void *reserved_ptr2;
228
229 /** \private Reserved member. */
230 const void *reserved_ptr3;
231
232 /** \private Reserved member. */
233 const void *reserved_ptr4;
234 } block;
235
236 /**
237 * \private Internal struct.
238 *
239 * Internal data which is used to store the state of the iterator.
240 * The exact format may vary between liblzma versions, so don't
241 * touch these in any way.
242 */
243 union {
244 /** \private Internal member. */
245 const void *p;
246
247 /** \private Internal member. */
248 size_t s;
249
250 /** \private Internal member. */
251 lzma_vli v;
252 } internal[6];
253 } lzma_index_iter;
254
255
256 /**
257 * \brief Operation mode for lzma_index_iter_next()
258 */
259 typedef enum {
260 LZMA_INDEX_ITER_ANY = 0,
261 /**<
262 * \brief Get the next Block or Stream
263 *
264 * Go to the next Block if the current Stream has at least
265 * one Block left. Otherwise go to the next Stream even if
266 * it has no Blocks. If the Stream has no Blocks
267 * (lzma_index_iter.stream.block_count == 0),
268 * lzma_index_iter.block will have undefined values.
269 */
270
271 LZMA_INDEX_ITER_STREAM = 1,
272 /**<
273 * \brief Get the next Stream
274 *
275 * Go to the next Stream even if the current Stream has
276 * unread Blocks left. If the next Stream has at least one
277 * Block, the iterator will point to the first Block.
278 * If there are no Blocks, lzma_index_iter.block will have
279 * undefined values.
280 */
281
282 LZMA_INDEX_ITER_BLOCK = 2,
283 /**<
284 * \brief Get the next Block
285 *
286 * Go to the next Block if the current Stream has at least
287 * one Block left. If the current Stream has no Blocks left,
288 * the next Stream with at least one Block is located and
289 * the iterator will be made to point to the first Block of
290 * that Stream.
291 */
292
293 LZMA_INDEX_ITER_NONEMPTY_BLOCK = 3
294 /**<
295 * \brief Get the next non-empty Block
296 *
297 * This is like LZMA_INDEX_ITER_BLOCK except that it will
298 * skip Blocks whose Uncompressed Size is zero.
299 */
300
301 } lzma_index_iter_mode;
302
303
304 /**
305 * \brief Calculate memory usage of lzma_index
306 *
307 * On disk, the size of the Index field depends on both the number of Records
308 * stored and the size of the Records (due to variable-length integer
309 * encoding). When the Index is kept in lzma_index structure, the memory usage
310 * depends only on the number of Records/Blocks stored in the Index(es), and
311 * in case of concatenated lzma_indexes, the number of Streams. The size in
312 * RAM is almost always significantly bigger than in the encoded form on disk.
313 *
314 * This function calculates an approximate amount of memory needed to hold
315 * the given number of Streams and Blocks in lzma_index structure. This
316 * value may vary between CPU architectures and also between liblzma versions
317 * if the internal implementation is modified.
318 *
319 * \param streams Number of Streams
320 * \param blocks Number of Blocks
321 *
322 * \return Approximate memory in bytes needed in a lzma_index structure.
323 */
324 extern LZMA_API(uint64_t) lzma_index_memusage(
325 lzma_vli streams, lzma_vli blocks) lzma_nothrow;
326
327
328 /**
329 * \brief Calculate the memory usage of an existing lzma_index
330 *
331 * This is a shorthand for lzma_index_memusage(lzma_index_stream_count(i),
332 * lzma_index_block_count(i)).
333 *
334 * \param i Pointer to lzma_index structure
335 *
336 * \return Approximate memory in bytes used by the lzma_index structure.
337 */
338 extern LZMA_API(uint64_t) lzma_index_memused(const lzma_index *i)
339 lzma_nothrow;
340
341
342 /**
343 * \brief Allocate and initialize a new lzma_index structure
344 *
345 * \param allocator lzma_allocator for custom allocator functions.
346 * Set to NULL to use malloc() and free().
347 *
348 * \return On success, a pointer to an empty initialized lzma_index is
349 * returned. If allocation fails, NULL is returned.
350 */
351 extern LZMA_API(lzma_index *) lzma_index_init(const lzma_allocator *allocator)
352 lzma_nothrow;
353
354
355 /**
356 * \brief Deallocate lzma_index
357 *
358 * If i is NULL, this does nothing.
359 *
360 * \param i Pointer to lzma_index structure to deallocate
361 * \param allocator lzma_allocator for custom allocator functions.
362 * Set to NULL to use malloc() and free().
363 */
364 extern LZMA_API(void) lzma_index_end(
365 lzma_index *i, const lzma_allocator *allocator) lzma_nothrow;
366
367
368 /**
369 * \brief Add a new Block to lzma_index
370 *
371 * \param i Pointer to a lzma_index structure
372 * \param allocator lzma_allocator for custom allocator
373 * functions. Set to NULL to use malloc()
374 * and free().
375 * \param unpadded_size Unpadded Size of a Block. This can be
376 * calculated with lzma_block_unpadded_size()
377 * after encoding or decoding the Block.
378 * \param uncompressed_size Uncompressed Size of a Block. This can be
379 * taken directly from lzma_block structure
380 * after encoding or decoding the Block.
381 *
382 * Appending a new Block does not invalidate iterators. For example,
383 * if an iterator was pointing to the end of the lzma_index, after
384 * lzma_index_append() it is possible to read the next Block with
385 * an existing iterator.
386 *
387 * \return Possible lzma_ret values:
388 * - LZMA_OK
389 * - LZMA_MEM_ERROR
390 * - LZMA_DATA_ERROR: Compressed or uncompressed size of the
391 * Stream or size of the Index field would grow too big.
392 * - LZMA_PROG_ERROR
393 */
394 extern LZMA_API(lzma_ret) lzma_index_append(
395 lzma_index *i, const lzma_allocator *allocator,
396 lzma_vli unpadded_size, lzma_vli uncompressed_size)
397 lzma_nothrow lzma_attr_warn_unused_result;
398
399
400 /**
401 * \brief Set the Stream Flags
402 *
403 * Set the Stream Flags of the last (and typically the only) Stream
404 * in lzma_index. This can be useful when reading information from the
405 * lzma_index, because to decode Blocks, knowing the integrity check type
406 * is needed.
407 *
408 * \param i Pointer to lzma_index structure
409 * \param stream_flags Pointer to lzma_stream_flags structure. This
410 * is copied into the internal preallocated
411 * structure, so the caller doesn't need to keep
412 * the flags' data available after calling this
413 * function.
414 *
415 * \return Possible lzma_ret values:
416 * - LZMA_OK
417 * - LZMA_OPTIONS_ERROR: Unsupported stream_flags->version.
418 * - LZMA_PROG_ERROR
419 */
420 extern LZMA_API(lzma_ret) lzma_index_stream_flags(
421 lzma_index *i, const lzma_stream_flags *stream_flags)
422 lzma_nothrow lzma_attr_warn_unused_result;
423
424
425 /**
426 * \brief Get the types of integrity Checks
427 *
428 * If lzma_index_stream_flags() is used to set the Stream Flags for
429 * every Stream, lzma_index_checks() can be used to get a bitmask to
430 * indicate which Check types have been used. It can be useful e.g. if
431 * showing the Check types to the user.
432 *
433 * The bitmask is 1 << check_id, e.g. CRC32 is 1 << 1 and SHA-256 is 1 << 10.
434 *
435 * \param i Pointer to lzma_index structure
436 *
437 * \return Bitmask indicating which Check types are used in the lzma_index
438 */
439 extern LZMA_API(uint32_t) lzma_index_checks(const lzma_index *i)
440 lzma_nothrow lzma_attr_pure;
441
442
443 /**
444 * \brief Set the amount of Stream Padding
445 *
446 * Set the amount of Stream Padding of the last (and typically the only)
447 * Stream in the lzma_index. This is needed when planning to do random-access
448 * reading within multiple concatenated Streams.
449 *
450 * By default, the amount of Stream Padding is assumed to be zero bytes.
451 *
452 * \return Possible lzma_ret values:
453 * - LZMA_OK
454 * - LZMA_DATA_ERROR: The file size would grow too big.
455 * - LZMA_PROG_ERROR
456 */
457 extern LZMA_API(lzma_ret) lzma_index_stream_padding(
458 lzma_index *i, lzma_vli stream_padding)
459 lzma_nothrow lzma_attr_warn_unused_result;
460
461
462 /**
463 * \brief Get the number of Streams
464 *
465 * \param i Pointer to lzma_index structure
466 *
467 * \return Number of Streams in the lzma_index
468 */
469 extern LZMA_API(lzma_vli) lzma_index_stream_count(const lzma_index *i)
470 lzma_nothrow lzma_attr_pure;
471
472
473 /**
474 * \brief Get the number of Blocks
475 *
476 * This returns the total number of Blocks in lzma_index. To get number
477 * of Blocks in individual Streams, use lzma_index_iter.
478 *
479 * \param i Pointer to lzma_index structure
480 *
481 * \return Number of blocks in the lzma_index
482 */
483 extern LZMA_API(lzma_vli) lzma_index_block_count(const lzma_index *i)
484 lzma_nothrow lzma_attr_pure;
485
486
487 /**
488 * \brief Get the size of the Index field as bytes
489 *
490 * This is needed to verify the Backward Size field in the Stream Footer.
491 *
492 * \param i Pointer to lzma_index structure
493 *
494 * \return Size in bytes of the Index
495 */
496 extern LZMA_API(lzma_vli) lzma_index_size(const lzma_index *i)
497 lzma_nothrow lzma_attr_pure;
498
499
500 /**
501 * \brief Get the total size of the Stream
502 *
503 * If multiple lzma_indexes have been combined, this works as if the Blocks
504 * were in a single Stream. This is useful if you are going to combine
505 * Blocks from multiple Streams into a single new Stream.
506 *
507 * \param i Pointer to lzma_index structure
508 *
509 * \return Size in bytes of the Stream (if all Blocks are combined
510 * into one Stream).
511 */
512 extern LZMA_API(lzma_vli) lzma_index_stream_size(const lzma_index *i)
513 lzma_nothrow lzma_attr_pure;
514
515
516 /**
517 * \brief Get the total size of the Blocks
518 *
519 * This doesn't include the Stream Header, Stream Footer, Stream Padding,
520 * or Index fields.
521 *
522 * \param i Pointer to lzma_index structure
523 *
524 * \return Size in bytes of all Blocks in the Stream(s)
525 */
526 extern LZMA_API(lzma_vli) lzma_index_total_size(const lzma_index *i)
527 lzma_nothrow lzma_attr_pure;
528
529
530 /**
531 * \brief Get the total size of the file
532 *
533 * When no lzma_indexes have been combined with lzma_index_cat() and there is
534 * no Stream Padding, this function is identical to lzma_index_stream_size().
535 * If multiple lzma_indexes have been combined, this includes also the headers
536 * of each separate Stream and the possible Stream Padding fields.
537 *
538 * \param i Pointer to lzma_index structure
539 *
540 * \return Total size of the .xz file in bytes
541 */
542 extern LZMA_API(lzma_vli) lzma_index_file_size(const lzma_index *i)
543 lzma_nothrow lzma_attr_pure;
544
545
546 /**
547 * \brief Get the uncompressed size of the file
548 *
549 * \param i Pointer to lzma_index structure
550 *
551 * \return Size in bytes of the uncompressed data in the file
552 */
553 extern LZMA_API(lzma_vli) lzma_index_uncompressed_size(const lzma_index *i)
554 lzma_nothrow lzma_attr_pure;
555
556
557 /**
558 * \brief Initialize an iterator
559 *
560 * This function associates the iterator with the given lzma_index, and calls
561 * lzma_index_iter_rewind() on the iterator.
562 *
563 * This function doesn't allocate any memory, thus there is no
564 * lzma_index_iter_end(). The iterator is valid as long as the
565 * associated lzma_index is valid, that is, until lzma_index_end() or
566 * using it as source in lzma_index_cat(). Specifically, lzma_index doesn't
567 * become invalid if new Blocks are added to it with lzma_index_append() or
568 * if it is used as the destination in lzma_index_cat().
569 *
570 * It is safe to make copies of an initialized lzma_index_iter, for example,
571 * to easily restart reading at some particular position.
572 *
573 * \param iter Pointer to a lzma_index_iter structure
574 * \param i lzma_index to which the iterator will be associated
575 */
576 extern LZMA_API(void) lzma_index_iter_init(
577 lzma_index_iter *iter, const lzma_index *i) lzma_nothrow;
578
579
580 /**
581 * \brief Rewind the iterator
582 *
583 * Rewind the iterator so that next call to lzma_index_iter_next() will
584 * return the first Block or Stream.
585 *
586 * \param iter Pointer to a lzma_index_iter structure
587 */
588 extern LZMA_API(void) lzma_index_iter_rewind(lzma_index_iter *iter)
589 lzma_nothrow;
590
591
592 /**
593 * \brief Get the next Block or Stream
594 *
595 * \param iter Iterator initialized with lzma_index_iter_init()
596 * \param mode Specify what kind of information the caller wants
597 * to get. See lzma_index_iter_mode for details.
598 *
599 * \return lzma_bool:
600 * - true if no Block or Stream matching the mode is found.
601 * *iter is not updated (failure).
602 * - false if the next Block or Stream matching the mode was
603 * found. *iter is updated (success).
604 */
605 extern LZMA_API(lzma_bool) lzma_index_iter_next(
606 lzma_index_iter *iter, lzma_index_iter_mode mode)
607 lzma_nothrow lzma_attr_warn_unused_result;
608
609
610 /**
611 * \brief Locate a Block
612 *
613 * If it is possible to seek in the .xz file, it is possible to parse
614 * the Index field(s) and use lzma_index_iter_locate() to do random-access
615 * reading with granularity of Block size.
616 *
617 * If the target is smaller than the uncompressed size of the Stream (can be
618 * checked with lzma_index_uncompressed_size()):
619 * - Information about the Stream and Block containing the requested
620 * uncompressed offset is stored into *iter.
621 * - Internal state of the iterator is adjusted so that
622 * lzma_index_iter_next() can be used to read subsequent Blocks or Streams.
623 *
624 * If the target is greater than the uncompressed size of the Stream, *iter
625 * is not modified.
626 *
627 * \param iter Iterator that was earlier initialized with
628 * lzma_index_iter_init().
629 * \param target Uncompressed target offset which the caller would
630 * like to locate from the Stream
631 *
632 * \return lzma_bool:
633 * - true if the target is greater than or equal to the
634 * uncompressed size of the Stream (failure)
635 * - false if the target is smaller than the uncompressed size
636 * of the Stream (success)
637 */
638 extern LZMA_API(lzma_bool) lzma_index_iter_locate(
639 lzma_index_iter *iter, lzma_vli target) lzma_nothrow;
640
641
642 /**
643 * \brief Concatenate lzma_indexes
644 *
645 * Concatenating lzma_indexes is useful when doing random-access reading in
646 * multi-Stream .xz file, or when combining multiple Streams into single
647 * Stream.
648 *
649 * \param[out] dest lzma_index after which src is appended
650 * \param src lzma_index to be appended after dest. If this
651 * function succeeds, the memory allocated for src
652 * is freed or moved to be part of dest, and all
653 * iterators pointing to src will become invalid.
654 * \param allocator lzma_allocator for custom allocator functions.
655 * Set to NULL to use malloc() and free().
656 *
657 * \return Possible lzma_ret values:
658 * - LZMA_OK: lzma_indexes were concatenated successfully.
659 * src is now a dangling pointer.
660 * - LZMA_DATA_ERROR: *dest would grow too big.
661 * - LZMA_MEM_ERROR
662 * - LZMA_PROG_ERROR
663 */
664 extern LZMA_API(lzma_ret) lzma_index_cat(lzma_index *dest, lzma_index *src,
665 const lzma_allocator *allocator)
666 lzma_nothrow lzma_attr_warn_unused_result;
667
668
669 /**
670 * \brief Duplicate lzma_index
671 *
672 * \param i Pointer to lzma_index structure to be duplicated
673 * \param allocator lzma_allocator for custom allocator functions.
674 * Set to NULL to use malloc() and free().
675 *
676 * \return A copy of the lzma_index, or NULL if memory allocation failed.
677 */
678 extern LZMA_API(lzma_index *) lzma_index_dup(
679 const lzma_index *i, const lzma_allocator *allocator)
680 lzma_nothrow lzma_attr_warn_unused_result;
681
682
683 /**
684 * \brief Initialize .xz Index encoder
685 *
686 * \param strm Pointer to properly prepared lzma_stream
687 * \param i Pointer to lzma_index which should be encoded.
688 *
689 * The valid `action' values for lzma_code() are LZMA_RUN and LZMA_FINISH.
690 * It is enough to use only one of them (you can choose freely).
691 *
692 * \return Possible lzma_ret values:
693 * - LZMA_OK: Initialization succeeded, continue with lzma_code().
694 * - LZMA_MEM_ERROR
695 * - LZMA_PROG_ERROR
696 */
697 extern LZMA_API(lzma_ret) lzma_index_encoder(
698 lzma_stream *strm, const lzma_index *i)
699 lzma_nothrow lzma_attr_warn_unused_result;
700
701
702 /**
703 * \brief Initialize .xz Index decoder
704 *
705 * \param strm Pointer to properly prepared lzma_stream
706 * \param[out] i The decoded Index will be made available via
707 * this pointer. Initially this function will
708 * set *i to NULL (the old value is ignored). If
709 * decoding succeeds (lzma_code() returns
710 * LZMA_STREAM_END), *i will be set to point
711 * to a new lzma_index, which the application
712 * has to later free with lzma_index_end().
713 * \param memlimit How much memory the resulting lzma_index is
714 * allowed to require. liblzma 5.2.3 and earlier
715 * don't allow 0 here and return LZMA_PROG_ERROR;
716 * later versions treat 0 as if 1 had been specified.
717 *
718 * Valid `action' arguments to lzma_code() are LZMA_RUN and LZMA_FINISH.
719 * There is no need to use LZMA_FINISH, but it's allowed because it may
720 * simplify certain types of applications.
721 *
722 * \return Possible lzma_ret values:
723 * - LZMA_OK: Initialization succeeded, continue with lzma_code().
724 * - LZMA_MEM_ERROR
725 * - LZMA_PROG_ERROR
726 *
727 * \note liblzma 5.2.3 and older list also LZMA_MEMLIMIT_ERROR here
728 * but that error code has never been possible from this
729 * initialization function.
730 */
731 extern LZMA_API(lzma_ret) lzma_index_decoder(
732 lzma_stream *strm, lzma_index **i, uint64_t memlimit)
733 lzma_nothrow lzma_attr_warn_unused_result;
734
735
736 /**
737 * \brief Single-call .xz Index encoder
738 *
739 * \note This function doesn't take allocator argument since all
740 * the internal data is allocated on stack.
741 *
742 * \param i lzma_index to be encoded
743 * \param[out] out Beginning of the output buffer
744 * \param[out] out_pos The next byte will be written to out[*out_pos].
745 * *out_pos is updated only if encoding succeeds.
746 * \param out_size Size of the out buffer; the first byte into
747 * which no data is written to is out[out_size].
748 *
749 * \return Possible lzma_ret values:
750 * - LZMA_OK: Encoding was successful.
751 * - LZMA_BUF_ERROR: Output buffer is too small. Use
752 * lzma_index_size() to find out how much output
753 * space is needed.
754 * - LZMA_PROG_ERROR
755 *
756 */
757 extern LZMA_API(lzma_ret) lzma_index_buffer_encode(const lzma_index *i,
758 uint8_t *out, size_t *out_pos, size_t out_size) lzma_nothrow;
759
760
761 /**
762 * \brief Single-call .xz Index decoder
763 *
764 * \param[out] i If decoding succeeds, *i will point to a new
765 * lzma_index, which the application has to
766 * later free with lzma_index_end(). If an error
767 * occurs, *i will be NULL. The old value of *i
768 * is always ignored and thus doesn't need to be
769 * initialized by the caller.
770 * \param[out] memlimit Pointer to how much memory the resulting
771 * lzma_index is allowed to require. The value
772 * pointed by this pointer is modified if and only
773 * if LZMA_MEMLIMIT_ERROR is returned.
774 * \param allocator lzma_allocator for custom allocator functions.
775 * Set to NULL to use malloc() and free().
776 * \param in Beginning of the input buffer
777 * \param in_pos The next byte will be read from in[*in_pos].
778 * *in_pos is updated only if decoding succeeds.
779 * \param in_size Size of the input buffer; the first byte that
780 * won't be read is in[in_size].
781 *
782 * \return Possible lzma_ret values:
783 * - LZMA_OK: Decoding was successful.
784 * - LZMA_MEM_ERROR
785 * - LZMA_MEMLIMIT_ERROR: Memory usage limit was reached.
786 * The minimum required memlimit value was stored to *memlimit.
787 * - LZMA_DATA_ERROR
788 * - LZMA_PROG_ERROR
789 */
790 extern LZMA_API(lzma_ret) lzma_index_buffer_decode(lzma_index **i,
791 uint64_t *memlimit, const lzma_allocator *allocator,
792 const uint8_t *in, size_t *in_pos, size_t in_size)
793 lzma_nothrow;
794
795
796 /**
797 * \brief Initialize a .xz file information decoder
798 *
799 * This decoder decodes the Stream Header, Stream Footer, Index, and
800 * Stream Padding field(s) from the input .xz file and stores the resulting
801 * combined index in *dest_index. This information can be used to get the
802 * uncompressed file size with lzma_index_uncompressed_size(*dest_index) or,
803 * for example, to implement random access reading by locating the Blocks
804 * in the Streams.
805 *
806 * To get the required information from the .xz file, lzma_code() may ask
807 * the application to seek in the input file by returning LZMA_SEEK_NEEDED
808 * and having the target file position specified in lzma_stream.seek_pos.
809 * The number of seeks required depends on the input file and how big buffers
810 * the application provides. When possible, the decoder will seek backward
811 * and forward in the given buffer to avoid useless seek requests. Thus, if
812 * the application provides the whole file at once, no external seeking will
813 * be required (that is, lzma_code() won't return LZMA_SEEK_NEEDED).
814 *
815 * The value in lzma_stream.total_in can be used to estimate how much data
816 * liblzma had to read to get the file information. However, due to seeking
817 * and the way total_in is updated, the value of total_in will be somewhat
818 * inaccurate (a little too big). Thus, total_in is a good estimate but don't
819 * expect to see the same exact value for the same file if you change the
820 * input buffer size or switch to a different liblzma version.
821 *
822 * Valid `action' arguments to lzma_code() are LZMA_RUN and LZMA_FINISH.
823 * You only need to use LZMA_RUN; LZMA_FINISH is only supported because it
824 * might be convenient for some applications. If you use LZMA_FINISH and if
825 * lzma_code() asks the application to seek, remember to reset `action' back
826 * to LZMA_RUN unless you hit the end of the file again.
827 *
828 * Possible return values from lzma_code():
829 * - LZMA_OK: All OK so far, more input needed
830 * - LZMA_SEEK_NEEDED: Provide more input starting from the absolute
831 * file position strm->seek_pos
832 * - LZMA_STREAM_END: Decoding was successful, *dest_index has been set
833 * - LZMA_FORMAT_ERROR: The input file is not in the .xz format (the
834 * expected magic bytes were not found from the beginning of the file)
835 * - LZMA_OPTIONS_ERROR: File looks valid but contains headers that aren't
836 * supported by this version of liblzma
837 * - LZMA_DATA_ERROR: File is corrupt
838 * - LZMA_BUF_ERROR
839 * - LZMA_MEM_ERROR
840 * - LZMA_MEMLIMIT_ERROR
841 * - LZMA_PROG_ERROR
842 *
843 * \param strm Pointer to a properly prepared lzma_stream
844 * \param[out] dest_index Pointer to a pointer where the decoder will put
845 * the decoded lzma_index. The old value
846 * of *dest_index is ignored (not freed).
847 * \param memlimit How much memory the resulting lzma_index is
848 * allowed to require. Use UINT64_MAX to
849 * effectively disable the limiter.
850 * \param file_size Size of the input .xz file
851 *
852 * \return Possible lzma_ret values:
853 * - LZMA_OK
854 * - LZMA_MEM_ERROR
855 * - LZMA_PROG_ERROR
856 */
857 extern LZMA_API(lzma_ret) lzma_file_info_decoder(
858 lzma_stream *strm, lzma_index **dest_index,
859 uint64_t memlimit, uint64_t file_size)
860 lzma_nothrow;
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