xref: /freebsd/contrib/xz/src/liblzma/api/lzma/base.h (revision 7899f917b1c0ea178f1d2be0cfb452086d079d23)
1 /* SPDX-License-Identifier: 0BSD */
2 
3 /**
4  * \file        lzma/base.h
5  * \brief       Data types and functions used in many places in liblzma API
6  * \note        Never include this file directly. Use <lzma.h> instead.
7  */
8 
9 /*
10  * Author: Lasse Collin
11  */
12 
13 #ifndef LZMA_H_INTERNAL
14 #	error Never include this file directly. Use <lzma.h> instead.
15 #endif
16 
17 
18 /**
19  * \brief       Boolean
20  *
21  * This is here because C89 doesn't have stdbool.h. To set a value for
22  * variables having type lzma_bool, you can use
23  *   - C99's 'true' and 'false' from stdbool.h;
24  *   - C++'s internal 'true' and 'false'; or
25  *   - integers one (true) and zero (false).
26  */
27 typedef unsigned char lzma_bool;
28 
29 
30 /**
31  * \brief       Type of reserved enumeration variable in structures
32  *
33  * To avoid breaking library ABI when new features are added, several
34  * structures contain extra variables that may be used in future. Since
35  * sizeof(enum) can be different than sizeof(int), and sizeof(enum) may
36  * even vary depending on the range of enumeration constants, we specify
37  * a separate type to be used for reserved enumeration variables. All
38  * enumeration constants in liblzma API will be non-negative and less
39  * than 128, which should guarantee that the ABI won't break even when
40  * new constants are added to existing enumerations.
41  */
42 typedef enum {
43 	LZMA_RESERVED_ENUM      = 0
44 } lzma_reserved_enum;
45 
46 
47 /**
48  * \brief       Return values used by several functions in liblzma
49  *
50  * Check the descriptions of specific functions to find out which return
51  * values they can return. With some functions the return values may have
52  * more specific meanings than described here; those differences are
53  * described per-function basis.
54  */
55 typedef enum {
56 	LZMA_OK                 = 0,
57 		/**<
58 		 * \brief       Operation completed successfully
59 		 */
60 
61 	LZMA_STREAM_END         = 1,
62 		/**<
63 		 * \brief       End of stream was reached
64 		 *
65 		 * In encoder, LZMA_SYNC_FLUSH, LZMA_FULL_FLUSH, or
66 		 * LZMA_FINISH was finished. In decoder, this indicates
67 		 * that all the data was successfully decoded.
68 		 *
69 		 * In all cases, when LZMA_STREAM_END is returned, the last
70 		 * output bytes should be picked from strm->next_out.
71 		 */
72 
73 	LZMA_NO_CHECK           = 2,
74 		/**<
75 		 * \brief       Input stream has no integrity check
76 		 *
77 		 * This return value can be returned only if the
78 		 * LZMA_TELL_NO_CHECK flag was used when initializing
79 		 * the decoder. LZMA_NO_CHECK is just a warning, and
80 		 * the decoding can be continued normally.
81 		 *
82 		 * It is possible to call lzma_get_check() immediately after
83 		 * lzma_code has returned LZMA_NO_CHECK. The result will
84 		 * naturally be LZMA_CHECK_NONE, but the possibility to call
85 		 * lzma_get_check() may be convenient in some applications.
86 		 */
87 
88 	LZMA_UNSUPPORTED_CHECK  = 3,
89 		/**<
90 		 * \brief       Cannot calculate the integrity check
91 		 *
92 		 * The usage of this return value is different in encoders
93 		 * and decoders.
94 		 *
95 		 * Encoders can return this value only from the initialization
96 		 * function. If initialization fails with this value, the
97 		 * encoding cannot be done, because there's no way to produce
98 		 * output with the correct integrity check.
99 		 *
100 		 * Decoders can return this value only from lzma_code() and
101 		 * only if the LZMA_TELL_UNSUPPORTED_CHECK flag was used when
102 		 * initializing the decoder. The decoding can still be
103 		 * continued normally even if the check type is unsupported,
104 		 * but naturally the check will not be validated, and possible
105 		 * errors may go undetected.
106 		 *
107 		 * With decoder, it is possible to call lzma_get_check()
108 		 * immediately after lzma_code() has returned
109 		 * LZMA_UNSUPPORTED_CHECK. This way it is possible to find
110 		 * out what the unsupported Check ID was.
111 		 */
112 
113 	LZMA_GET_CHECK          = 4,
114 		/**<
115 		 * \brief       Integrity check type is now available
116 		 *
117 		 * This value can be returned only by the lzma_code() function
118 		 * and only if the decoder was initialized with the
119 		 * LZMA_TELL_ANY_CHECK flag. LZMA_GET_CHECK tells the
120 		 * application that it may now call lzma_get_check() to find
121 		 * out the Check ID. This can be used, for example, to
122 		 * implement a decoder that accepts only files that have
123 		 * strong enough integrity check.
124 		 */
125 
126 	LZMA_MEM_ERROR          = 5,
127 		/**<
128 		 * \brief       Cannot allocate memory
129 		 *
130 		 * Memory allocation failed, or the size of the allocation
131 		 * would be greater than SIZE_MAX.
132 		 *
133 		 * Due to internal implementation reasons, the coding cannot
134 		 * be continued even if more memory were made available after
135 		 * LZMA_MEM_ERROR.
136 		 */
137 
138 	LZMA_MEMLIMIT_ERROR     = 6,
139 		/**<
140 		 * \brief       Memory usage limit was reached
141 		 *
142 		 * Decoder would need more memory than allowed by the
143 		 * specified memory usage limit. To continue decoding,
144 		 * the memory usage limit has to be increased with
145 		 * lzma_memlimit_set().
146 		 *
147 		 * liblzma 5.2.6 and earlier had a bug in single-threaded .xz
148 		 * decoder (lzma_stream_decoder()) which made it impossible
149 		 * to continue decoding after LZMA_MEMLIMIT_ERROR even if
150 		 * the limit was increased using lzma_memlimit_set().
151 		 * Other decoders worked correctly.
152 		 */
153 
154 	LZMA_FORMAT_ERROR       = 7,
155 		/**<
156 		 * \brief       File format not recognized
157 		 *
158 		 * The decoder did not recognize the input as supported file
159 		 * format. This error can occur, for example, when trying to
160 		 * decode .lzma format file with lzma_stream_decoder,
161 		 * because lzma_stream_decoder accepts only the .xz format.
162 		 */
163 
164 	LZMA_OPTIONS_ERROR      = 8,
165 		/**<
166 		 * \brief       Invalid or unsupported options
167 		 *
168 		 * Invalid or unsupported options, for example
169 		 *  - unsupported filter(s) or filter options; or
170 		 *  - reserved bits set in headers (decoder only).
171 		 *
172 		 * Rebuilding liblzma with more features enabled, or
173 		 * upgrading to a newer version of liblzma may help.
174 		 */
175 
176 	LZMA_DATA_ERROR         = 9,
177 		/**<
178 		 * \brief       Data is corrupt
179 		 *
180 		 * The usage of this return value is different in encoders
181 		 * and decoders. In both encoder and decoder, the coding
182 		 * cannot continue after this error.
183 		 *
184 		 * Encoders return this if size limits of the target file
185 		 * format would be exceeded. These limits are huge, thus
186 		 * getting this error from an encoder is mostly theoretical.
187 		 * For example, the maximum compressed and uncompressed
188 		 * size of a .xz Stream is roughly 8 EiB (2^63 bytes).
189 		 *
190 		 * Decoders return this error if the input data is corrupt.
191 		 * This can mean, for example, invalid CRC32 in headers
192 		 * or invalid check of uncompressed data.
193 		 */
194 
195 	LZMA_BUF_ERROR          = 10,
196 		/**<
197 		 * \brief       No progress is possible
198 		 *
199 		 * This error code is returned when the coder cannot consume
200 		 * any new input and produce any new output. The most common
201 		 * reason for this error is that the input stream being
202 		 * decoded is truncated or corrupt.
203 		 *
204 		 * This error is not fatal. Coding can be continued normally
205 		 * by providing more input and/or more output space, if
206 		 * possible.
207 		 *
208 		 * Typically the first call to lzma_code() that can do no
209 		 * progress returns LZMA_OK instead of LZMA_BUF_ERROR. Only
210 		 * the second consecutive call doing no progress will return
211 		 * LZMA_BUF_ERROR. This is intentional.
212 		 *
213 		 * With zlib, Z_BUF_ERROR may be returned even if the
214 		 * application is doing nothing wrong, so apps will need
215 		 * to handle Z_BUF_ERROR specially. The above hack
216 		 * guarantees that liblzma never returns LZMA_BUF_ERROR
217 		 * to properly written applications unless the input file
218 		 * is truncated or corrupt. This should simplify the
219 		 * applications a little.
220 		 */
221 
222 	LZMA_PROG_ERROR         = 11,
223 		/**<
224 		 * \brief       Programming error
225 		 *
226 		 * This indicates that the arguments given to the function are
227 		 * invalid or the internal state of the decoder is corrupt.
228 		 *   - Function arguments are invalid or the structures
229 		 *     pointed by the argument pointers are invalid
230 		 *     e.g. if strm->next_out has been set to NULL and
231 		 *     strm->avail_out > 0 when calling lzma_code().
232 		 *   - lzma_* functions have been called in wrong order
233 		 *     e.g. lzma_code() was called right after lzma_end().
234 		 *   - If errors occur randomly, the reason might be flaky
235 		 *     hardware.
236 		 *
237 		 * If you think that your code is correct, this error code
238 		 * can be a sign of a bug in liblzma. See the documentation
239 		 * how to report bugs.
240 		 */
241 
242 	LZMA_SEEK_NEEDED        = 12,
243 		/**<
244 		 * \brief       Request to change the input file position
245 		 *
246 		 * Some coders can do random access in the input file. The
247 		 * initialization functions of these coders take the file size
248 		 * as an argument. No other coders can return LZMA_SEEK_NEEDED.
249 		 *
250 		 * When this value is returned, the application must seek to
251 		 * the file position given in lzma_stream.seek_pos. This value
252 		 * is guaranteed to never exceed the file size that was
253 		 * specified at the coder initialization.
254 		 *
255 		 * After seeking the application should read new input and
256 		 * pass it normally via lzma_stream.next_in and .avail_in.
257 		 */
258 
259 	/*
260 	 * These enumerations may be used internally by liblzma
261 	 * but they will never be returned to applications.
262 	 */
263 	LZMA_RET_INTERNAL1      = 101,
264 	LZMA_RET_INTERNAL2      = 102,
265 	LZMA_RET_INTERNAL3      = 103,
266 	LZMA_RET_INTERNAL4      = 104,
267 	LZMA_RET_INTERNAL5      = 105,
268 	LZMA_RET_INTERNAL6      = 106,
269 	LZMA_RET_INTERNAL7      = 107,
270 	LZMA_RET_INTERNAL8      = 108
271 } lzma_ret;
272 
273 
274 /**
275  * \brief       The 'action' argument for lzma_code()
276  *
277  * After the first use of LZMA_SYNC_FLUSH, LZMA_FULL_FLUSH, LZMA_FULL_BARRIER,
278  * or LZMA_FINISH, the same 'action' must be used until lzma_code() returns
279  * LZMA_STREAM_END. Also, the amount of input (that is, strm->avail_in) must
280  * not be modified by the application until lzma_code() returns
281  * LZMA_STREAM_END. Changing the 'action' or modifying the amount of input
282  * will make lzma_code() return LZMA_PROG_ERROR.
283  */
284 typedef enum {
285 	LZMA_RUN = 0,
286 		/**<
287 		 * \brief       Continue coding
288 		 *
289 		 * Encoder: Encode as much input as possible. Some internal
290 		 * buffering will probably be done (depends on the filter
291 		 * chain in use), which causes latency: the input used won't
292 		 * usually be decodeable from the output of the same
293 		 * lzma_code() call.
294 		 *
295 		 * Decoder: Decode as much input as possible and produce as
296 		 * much output as possible.
297 		 */
298 
299 	LZMA_SYNC_FLUSH = 1,
300 		/**<
301 		 * \brief       Make all the input available at output
302 		 *
303 		 * Normally the encoder introduces some latency.
304 		 * LZMA_SYNC_FLUSH forces all the buffered data to be
305 		 * available at output without resetting the internal
306 		 * state of the encoder. This way it is possible to use
307 		 * compressed stream for example for communication over
308 		 * network.
309 		 *
310 		 * Only some filters support LZMA_SYNC_FLUSH. Trying to use
311 		 * LZMA_SYNC_FLUSH with filters that don't support it will
312 		 * make lzma_code() return LZMA_OPTIONS_ERROR. For example,
313 		 * LZMA1 doesn't support LZMA_SYNC_FLUSH but LZMA2 does.
314 		 *
315 		 * Using LZMA_SYNC_FLUSH very often can dramatically reduce
316 		 * the compression ratio. With some filters (for example,
317 		 * LZMA2), fine-tuning the compression options may help
318 		 * mitigate this problem significantly (for example,
319 		 * match finder with LZMA2).
320 		 *
321 		 * Decoders don't support LZMA_SYNC_FLUSH.
322 		 */
323 
324 	LZMA_FULL_FLUSH = 2,
325 		/**<
326 		 * \brief       Finish encoding of the current Block
327 		 *
328 		 * All the input data going to the current Block must have
329 		 * been given to the encoder (the last bytes can still be
330 		 * pending in *next_in). Call lzma_code() with LZMA_FULL_FLUSH
331 		 * until it returns LZMA_STREAM_END. Then continue normally
332 		 * with LZMA_RUN or finish the Stream with LZMA_FINISH.
333 		 *
334 		 * This action is currently supported only by Stream encoder
335 		 * and easy encoder (which uses Stream encoder). If there is
336 		 * no unfinished Block, no empty Block is created.
337 		 */
338 
339 	LZMA_FULL_BARRIER = 4,
340 		/**<
341 		 * \brief       Finish encoding of the current Block
342 		 *
343 		 * This is like LZMA_FULL_FLUSH except that this doesn't
344 		 * necessarily wait until all the input has been made
345 		 * available via the output buffer. That is, lzma_code()
346 		 * might return LZMA_STREAM_END as soon as all the input
347 		 * has been consumed (avail_in == 0).
348 		 *
349 		 * LZMA_FULL_BARRIER is useful with a threaded encoder if
350 		 * one wants to split the .xz Stream into Blocks at specific
351 		 * offsets but doesn't care if the output isn't flushed
352 		 * immediately. Using LZMA_FULL_BARRIER allows keeping
353 		 * the threads busy while LZMA_FULL_FLUSH would make
354 		 * lzma_code() wait until all the threads have finished
355 		 * until more data could be passed to the encoder.
356 		 *
357 		 * With a lzma_stream initialized with the single-threaded
358 		 * lzma_stream_encoder() or lzma_easy_encoder(),
359 		 * LZMA_FULL_BARRIER is an alias for LZMA_FULL_FLUSH.
360 		 */
361 
362 	LZMA_FINISH = 3
363 		/**<
364 		 * \brief       Finish the coding operation
365 		 *
366 		 * All the input data must have been given to the encoder
367 		 * (the last bytes can still be pending in next_in).
368 		 * Call lzma_code() with LZMA_FINISH until it returns
369 		 * LZMA_STREAM_END. Once LZMA_FINISH has been used,
370 		 * the amount of input must no longer be changed by
371 		 * the application.
372 		 *
373 		 * When decoding, using LZMA_FINISH is optional unless the
374 		 * LZMA_CONCATENATED flag was used when the decoder was
375 		 * initialized. When LZMA_CONCATENATED was not used, the only
376 		 * effect of LZMA_FINISH is that the amount of input must not
377 		 * be changed just like in the encoder.
378 		 */
379 } lzma_action;
380 
381 
382 /**
383  * \brief       Custom functions for memory handling
384  *
385  * A pointer to lzma_allocator may be passed via lzma_stream structure
386  * to liblzma, and some advanced functions take a pointer to lzma_allocator
387  * as a separate function argument. The library will use the functions
388  * specified in lzma_allocator for memory handling instead of the default
389  * malloc() and free(). C++ users should note that the custom memory
390  * handling functions must not throw exceptions.
391  *
392  * Single-threaded mode only: liblzma doesn't make an internal copy of
393  * lzma_allocator. Thus, it is OK to change these function pointers in
394  * the middle of the coding process, but obviously it must be done
395  * carefully to make sure that the replacement 'free' can deallocate
396  * memory allocated by the earlier 'alloc' function(s).
397  *
398  * Multithreaded mode: liblzma might internally store pointers to the
399  * lzma_allocator given via the lzma_stream structure. The application
400  * must not change the allocator pointer in lzma_stream or the contents
401  * of the pointed lzma_allocator structure until lzma_end() has been used
402  * to free the memory associated with that lzma_stream. The allocation
403  * functions might be called simultaneously from multiple threads, and
404  * thus they must be thread safe.
405  */
406 typedef struct {
407 	/**
408 	 * \brief       Pointer to a custom memory allocation function
409 	 *
410 	 * If you don't want a custom allocator, but still want
411 	 * custom free(), set this to NULL and liblzma will use
412 	 * the standard malloc().
413 	 *
414 	 * \param       opaque  lzma_allocator.opaque (see below)
415 	 * \param       nmemb   Number of elements like in calloc(). liblzma
416 	 *                      will always set nmemb to 1, so it is safe to
417 	 *                      ignore nmemb in a custom allocator if you like.
418 	 *                      The nmemb argument exists only for
419 	 *                      compatibility with zlib and libbzip2.
420 	 * \param       size    Size of an element in bytes.
421 	 *                      liblzma never sets this to zero.
422 	 *
423 	 * \return      Pointer to the beginning of a memory block of
424 	 *              'size' bytes, or NULL if allocation fails
425 	 *              for some reason. When allocation fails, functions
426 	 *              of liblzma return LZMA_MEM_ERROR.
427 	 *
428 	 * The allocator should not waste time zeroing the allocated buffers.
429 	 * This is not only about speed, but also memory usage, since the
430 	 * operating system kernel doesn't necessarily allocate the requested
431 	 * memory in physical memory until it is actually used. With small
432 	 * input files, liblzma may actually need only a fraction of the
433 	 * memory that it requested for allocation.
434 	 *
435 	 * \note        LZMA_MEM_ERROR is also used when the size of the
436 	 *              allocation would be greater than SIZE_MAX. Thus,
437 	 *              don't assume that the custom allocator must have
438 	 *              returned NULL if some function from liblzma
439 	 *              returns LZMA_MEM_ERROR.
440 	 */
441 	void *(LZMA_API_CALL *alloc)(void *opaque, size_t nmemb, size_t size);
442 
443 	/**
444 	 * \brief       Pointer to a custom memory freeing function
445 	 *
446 	 * If you don't want a custom freeing function, but still
447 	 * want a custom allocator, set this to NULL and liblzma
448 	 * will use the standard free().
449 	 *
450 	 * \param       opaque  lzma_allocator.opaque (see below)
451 	 * \param       ptr     Pointer returned by lzma_allocator.alloc(),
452 	 *                      or when it is set to NULL, a pointer returned
453 	 *                      by the standard malloc().
454 	 */
455 	void (LZMA_API_CALL *free)(void *opaque, void *ptr);
456 
457 	/**
458 	 * \brief       Pointer passed to .alloc() and .free()
459 	 *
460 	 * opaque is passed as the first argument to lzma_allocator.alloc()
461 	 * and lzma_allocator.free(). This intended to ease implementing
462 	 * custom memory allocation functions for use with liblzma.
463 	 *
464 	 * If you don't need this, you should set this to NULL.
465 	 */
466 	void *opaque;
467 
468 } lzma_allocator;
469 
470 
471 /**
472  * \brief       Internal data structure
473  *
474  * The contents of this structure is not visible outside the library.
475  */
476 typedef struct lzma_internal_s lzma_internal;
477 
478 
479 /**
480  * \brief       Passing data to and from liblzma
481  *
482  * The lzma_stream structure is used for
483  *  - passing pointers to input and output buffers to liblzma;
484  *  - defining custom memory handler functions; and
485  *  - holding a pointer to coder-specific internal data structures.
486  *
487  * Typical usage:
488  *
489  *  - After allocating lzma_stream (on stack or with malloc()), it must be
490  *    initialized to LZMA_STREAM_INIT (see LZMA_STREAM_INIT for details).
491  *
492  *  - Initialize a coder to the lzma_stream, for example by using
493  *    lzma_easy_encoder() or lzma_auto_decoder(). Some notes:
494  *      - In contrast to zlib, strm->next_in and strm->next_out are
495  *        ignored by all initialization functions, thus it is safe
496  *        to not initialize them yet.
497  *      - The initialization functions always set strm->total_in and
498  *        strm->total_out to zero.
499  *      - If the initialization function fails, no memory is left allocated
500  *        that would require freeing with lzma_end() even if some memory was
501  *        associated with the lzma_stream structure when the initialization
502  *        function was called.
503  *
504  *  - Use lzma_code() to do the actual work.
505  *
506  *  - Once the coding has been finished, the existing lzma_stream can be
507  *    reused. It is OK to reuse lzma_stream with different initialization
508  *    function without calling lzma_end() first. Old allocations are
509  *    automatically freed.
510  *
511  *  - Finally, use lzma_end() to free the allocated memory. lzma_end() never
512  *    frees the lzma_stream structure itself.
513  *
514  * Application may modify the values of total_in and total_out as it wants.
515  * They are updated by liblzma to match the amount of data read and
516  * written but aren't used for anything else except as a possible return
517  * values from lzma_get_progress().
518  */
519 typedef struct {
520 	const uint8_t *next_in; /**< Pointer to the next input byte. */
521 	size_t avail_in;    /**< Number of available input bytes in next_in. */
522 	uint64_t total_in;  /**< Total number of bytes read by liblzma. */
523 
524 	uint8_t *next_out;  /**< Pointer to the next output position. */
525 	size_t avail_out;   /**< Amount of free space in next_out. */
526 	uint64_t total_out; /**< Total number of bytes written by liblzma. */
527 
528 	/**
529 	 * \brief       Custom memory allocation functions
530 	 *
531 	 * In most cases this is NULL which makes liblzma use
532 	 * the standard malloc() and free().
533 	 *
534 	 * \note        In 5.0.x this is not a const pointer.
535 	 */
536 	const lzma_allocator *allocator;
537 
538 	/** Internal state is not visible to applications. */
539 	lzma_internal *internal;
540 
541 	/*
542 	 * Reserved space to allow possible future extensions without
543 	 * breaking the ABI. Excluding the initialization of this structure,
544 	 * you should not touch these, because the names of these variables
545 	 * may change.
546 	 */
547 
548 	/** \private     Reserved member. */
549 	void *reserved_ptr1;
550 
551 	/** \private     Reserved member. */
552 	void *reserved_ptr2;
553 
554 	/** \private     Reserved member. */
555 	void *reserved_ptr3;
556 
557 	/** \private     Reserved member. */
558 	void *reserved_ptr4;
559 
560 	/**
561 	 * \brief       New seek input position for LZMA_SEEK_NEEDED
562 	 *
563 	 * When lzma_code() returns LZMA_SEEK_NEEDED, the new input position
564 	 * needed by liblzma will be available seek_pos. The value is
565 	 * guaranteed to not exceed the file size that was specified when
566 	 * this lzma_stream was initialized.
567 	 *
568 	 * In all other situations the value of this variable is undefined.
569 	 */
570 	uint64_t seek_pos;
571 
572 	/** \private     Reserved member. */
573 	uint64_t reserved_int2;
574 
575 	/** \private     Reserved member. */
576 	size_t reserved_int3;
577 
578 	/** \private     Reserved member. */
579 	size_t reserved_int4;
580 
581 	/** \private     Reserved member. */
582 	lzma_reserved_enum reserved_enum1;
583 
584 	/** \private     Reserved member. */
585 	lzma_reserved_enum reserved_enum2;
586 
587 } lzma_stream;
588 
589 
590 /**
591  * \brief       Initialization for lzma_stream
592  *
593  * When you declare an instance of lzma_stream, you can immediately
594  * initialize it so that initialization functions know that no memory
595  * has been allocated yet:
596  *
597  *     lzma_stream strm = LZMA_STREAM_INIT;
598  *
599  * If you need to initialize a dynamically allocated lzma_stream, you can use
600  * memset(strm_pointer, 0, sizeof(lzma_stream)). Strictly speaking, this
601  * violates the C standard since NULL may have different internal
602  * representation than zero, but it should be portable enough in practice.
603  * Anyway, for maximum portability, you can use something like this:
604  *
605  *     lzma_stream tmp = LZMA_STREAM_INIT;
606  *     *strm = tmp;
607  */
608 #define LZMA_STREAM_INIT \
609 	{ NULL, 0, 0, NULL, 0, 0, NULL, NULL, \
610 	NULL, NULL, NULL, NULL, 0, 0, 0, 0, \
611 	LZMA_RESERVED_ENUM, LZMA_RESERVED_ENUM }
612 
613 
614 /**
615  * \brief       Encode or decode data
616  *
617  * Once the lzma_stream has been successfully initialized (e.g. with
618  * lzma_stream_encoder()), the actual encoding or decoding is done
619  * using this function. The application has to update strm->next_in,
620  * strm->avail_in, strm->next_out, and strm->avail_out to pass input
621  * to and get output from liblzma.
622  *
623  * See the description of the coder-specific initialization function to find
624  * out what 'action' values are supported by the coder.
625  *
626  * \param       strm    Pointer to lzma_stream that is at least initialized
627  *                      with LZMA_STREAM_INIT.
628  * \param       action  Action for this function to take. Must be a valid
629  *                      lzma_action enum value.
630  *
631  * \return      Any valid lzma_ret. See the lzma_ret enum description for more
632  *              information.
633  */
634 extern LZMA_API(lzma_ret) lzma_code(lzma_stream *strm, lzma_action action)
635 		lzma_nothrow lzma_attr_warn_unused_result;
636 
637 
638 /**
639  * \brief       Free memory allocated for the coder data structures
640  *
641  * After lzma_end(strm), strm->internal is guaranteed to be NULL. No other
642  * members of the lzma_stream structure are touched.
643  *
644  * \note        zlib indicates an error if application end()s unfinished
645  *              stream structure. liblzma doesn't do this, and assumes that
646  *              application knows what it is doing.
647  *
648  * \param       strm    Pointer to lzma_stream that is at least initialized
649  *                      with LZMA_STREAM_INIT.
650  */
651 extern LZMA_API(void) lzma_end(lzma_stream *strm) lzma_nothrow;
652 
653 
654 /**
655  * \brief       Get progress information
656  *
657  * In single-threaded mode, applications can get progress information from
658  * strm->total_in and strm->total_out. In multi-threaded mode this is less
659  * useful because a significant amount of both input and output data gets
660  * buffered internally by liblzma. This makes total_in and total_out give
661  * misleading information and also makes the progress indicator updates
662  * non-smooth.
663  *
664  * This function gives realistic progress information also in multi-threaded
665  * mode by taking into account the progress made by each thread. In
666  * single-threaded mode *progress_in and *progress_out are set to
667  * strm->total_in and strm->total_out, respectively.
668  *
669  * \param       strm          Pointer to lzma_stream that is at least
670  *                            initialized with LZMA_STREAM_INIT.
671  * \param[out]  progress_in   Pointer to the number of input bytes processed.
672  * \param[out]  progress_out  Pointer to the number of output bytes processed.
673  */
674 extern LZMA_API(void) lzma_get_progress(lzma_stream *strm,
675 		uint64_t *progress_in, uint64_t *progress_out) lzma_nothrow;
676 
677 
678 /**
679  * \brief       Get the memory usage of decoder filter chain
680  *
681  * This function is currently supported only when *strm has been initialized
682  * with a function that takes a memlimit argument. With other functions, you
683  * should use e.g. lzma_raw_encoder_memusage() or lzma_raw_decoder_memusage()
684  * to estimate the memory requirements.
685  *
686  * This function is useful e.g. after LZMA_MEMLIMIT_ERROR to find out how big
687  * the memory usage limit should have been to decode the input. Note that
688  * this may give misleading information if decoding .xz Streams that have
689  * multiple Blocks, because each Block can have different memory requirements.
690  *
691  * \param       strm    Pointer to lzma_stream that is at least initialized
692  *                      with LZMA_STREAM_INIT.
693  *
694  * \return      How much memory is currently allocated for the filter
695  *              decoders. If no filter chain is currently allocated,
696  *              some non-zero value is still returned, which is less than
697  *              or equal to what any filter chain would indicate as its
698  *              memory requirement.
699  *
700  *              If this function isn't supported by *strm or some other error
701  *              occurs, zero is returned.
702  */
703 extern LZMA_API(uint64_t) lzma_memusage(const lzma_stream *strm)
704 		lzma_nothrow lzma_attr_pure;
705 
706 
707 /**
708  * \brief       Get the current memory usage limit
709  *
710  * This function is supported only when *strm has been initialized with
711  * a function that takes a memlimit argument.
712  *
713  * \param       strm    Pointer to lzma_stream that is at least initialized
714  *                      with LZMA_STREAM_INIT.
715  *
716  * \return      On success, the current memory usage limit is returned
717  *              (always non-zero). On error, zero is returned.
718  */
719 extern LZMA_API(uint64_t) lzma_memlimit_get(const lzma_stream *strm)
720 		lzma_nothrow lzma_attr_pure;
721 
722 
723 /**
724  * \brief       Set the memory usage limit
725  *
726  * This function is supported only when *strm has been initialized with
727  * a function that takes a memlimit argument.
728  *
729  * liblzma 5.2.3 and earlier has a bug where memlimit value of 0 causes
730  * this function to do nothing (leaving the limit unchanged) and still
731  * return LZMA_OK. Later versions treat 0 as if 1 had been specified (so
732  * lzma_memlimit_get() will return 1 even if you specify 0 here).
733  *
734  * liblzma 5.2.6 and earlier had a bug in single-threaded .xz decoder
735  * (lzma_stream_decoder()) which made it impossible to continue decoding
736  * after LZMA_MEMLIMIT_ERROR even if the limit was increased using
737  * lzma_memlimit_set(). Other decoders worked correctly.
738  *
739  * \return      Possible lzma_ret values:
740  *              - LZMA_OK: New memory usage limit successfully set.
741  *              - LZMA_MEMLIMIT_ERROR: The new limit is too small.
742  *                The limit was not changed.
743  *              - LZMA_PROG_ERROR: Invalid arguments, e.g. *strm doesn't
744  *                support memory usage limit.
745  */
746 extern LZMA_API(lzma_ret) lzma_memlimit_set(
747 		lzma_stream *strm, uint64_t memlimit) lzma_nothrow;
748