path: root/src/liblzma/api/lzma/base.h

/**
 * \file        lzma/base.h
 * \brief       Data types and functions used in many places of the public API
 *
 * \author      Copyright (C) 1999-2006 Igor Pavlov
 * \author      Copyright (C) 2007 Lasse Collin
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 */

#ifndef LZMA_H_INTERNAL
#	error Never include this file directly. Use <lzma.h> instead.
#endif


/**
 * \brief       Boolean
 *
 * This is here because C89 doesn't have stdbool.h. To set a value for
 * variables having type lzma_bool, you can use
 *   - C99's `true' and `false' from stdbool.h;
 *   - C++'s internal `true' and `false'; or
 *   - integers one (true) and zero (false).
 */
typedef unsigned char lzma_bool;


/**
 * \brief       Type of reserved enumeration variable in structures
 *
 * To avoid breaking library ABI when new features are added, several
 * structures contain extra variables that may be used in future. Since
 * sizeof(enum) can be different than sizeof(int), and sizeof(enum) may
 * even vary depending on the range of enumeration constants, we specify
 * a separate type to be used for reserved enumeration variables. All
 * enumeration constants in liblzma API will be non-negative and less
 * than 128, which should guarantee that the ABI won't break even when
 * new constants are added to existing enumerations.
 */
typedef enum {
	LZMA_RESERVED_ENUM      = 0
} lzma_reserved_enum;


/**
 * \brief       Return values used by several functions in liblzma
 *
 * Check the descriptions of specific functions to find out which return
 * values they can return. With some functions the return values may have
 * more specific meanings than described here; those differences are
 * described per-function basis.
 */
typedef enum {
	LZMA_OK                 = 0,
		/**<
		 * \brief       Operation completed successfully
		 */

	LZMA_STREAM_END         = 1,
		/**<
		 * \brief       End of stream was reached
		 *
		 * In encoder, LZMA_SYNC_FLUSH, LZMA_FULL_FLUSH, or
		 * LZMA_FINISH was finished. In decoder, this indicates
		 * that all the data was successfully decoded.
		 *
		 * In all cases, when LZMA_STREAM_END is returned, the last
		 * output bytes should be picked from strm->next_out.
		 */

	LZMA_NO_CHECK           = 2,
		/**<
		 * \brief       Input stream has no integrity check
		 *
		 * This return value can be returned only if the
		 * LZMA_TELL_NO_CHECK flag was used when initializing
		 * the decoder. LZMA_NO_CHECK is just a warning, and
		 * the decoding can be continued normally.
		 *
		 * It is possible to call lzma_get_check() immediatelly after
		 * lzma_code has returned LZMA_NO_CHECK. The result will
		 * naturally be LZMA_CHECK_NONE, but the possibility to call
		 * lzma_get_check() may be convenient in some applications.
		 */

	LZMA_UNSUPPORTED_CHECK  = 3,
		/**<
		 * \brief       Cannot calculate the integrity check
		 *
		 * The usage of this return value is slightly different in
		 * encoders and decoders.
		 *
		 * Encoders can return this value only from the initialization
		 * function. If initialization fails with this value, the
		 * encoding cannot be done, because there's no way to produce
		 * output with the correct integrity check.
		 *
		 * Decoders can return this value only from the lzma_code
		 * function and only if the LZMA_TELL_UNSUPPORTED_CHECK flag
		 * was used when initializing the decoder. The decoding can
		 * still be continued normally even if the check type is
		 * unsupported, but naturally the check will not be validated,
		 * and possible errors may go undetected.
		 *
		 * With decoder, it is possible to call lzma_get_check()
		 * immediatelly after lzma_code has returned
		 * LZMA_UNSUPPORTED_CHECK. This way it is possible to find
		 * out what the unsupported Check ID was.
		 */

	LZMA_GET_CHECK          = 4,
		/**<
		 * \brief       Integrity check type is now available
		 *
		 * This value can be returned only by the lzma_code() function
		 * and only if the decoder was initialized with the
		 * LZMA_TELL_ANY_CHECK flag. LZMA_GET_CHECK tells the
		 * application that it may now call lzma_get_check() to find
		 * out the Check ID. This can be used, for example, to
		 * implement a decoder that accepts only files that have
		 * strong enough integrity check.
		 */

	LZMA_MEM_ERROR          = 5,
		/**<
		 * \brief       Cannot allocate memory
		 *
		 * Memory allocation failed, or the size of the allocation
		 * would be greater than SIZE_MAX.
		 *
		 * Due to lazy coding, the coding cannot be continued even
		 * if more memory were made available after LZMA_MEM_ERROR.
		 */

	LZMA_MEMLIMIT_ERROR     = 6,
		/**
		 * \brief       Memory usage limit was reached
		 *
		 * Decoder would need more memory than allowed by the
		 * specified memory usage limit. To continue decoding,
		 * the memory usage limit has to be increased. See functions
		 * lzma_memlimit_get() and lzma_memlimit_set().
		 */

	LZMA_FORMAT_ERROR       = 7,
		/**<
		 * \brief       Unknown file format
		 *
		 * The decoder did not recognize the input as supported file
		 * format. This error can occur, for example, when trying to
		 * decode LZMA_Alone format file with lzma_stream_decoder,
		 * because lzma_stream_decoder accepts only the new .lzma
		 * format.
		 */

	LZMA_OPTIONS_ERROR      = 8,
		/**<
		 * \brief       Invalid or unsupported options
		 *
		 * Invalid or unsupported options, for example
		 *  - unsupported filter(s) or filter options; or
		 *  - reserved bits set in headers (decoder only).
		 *
		 * Rebuilding liblzma with more features enabled, or
		 * upgrading to a newer version of liblzma may help.
		 */

	LZMA_DATA_ERROR         = 9,
		/**<
		 * \brief       Data is corrupt
		 *
		 * The usage of this return value is different in encoders
		 * and decoders. In both encoder and decoder, the coding
		 * cannot continue after this error.
		 *
		 * Encoders return this if size limits of the target file
		 * format would be exceeded. These limits are huge, thus
		 * getting this error from an encoder is mostly theoretical.
		 * For example, the maximum compressed and uncompressed
		 * size of a Stream created with lzma_stream_encoder is
		 * 2^63 - 1 bytes (one byte less than 8 EiB).
		 *
		 * Decoders return this error if the input data is corrupt.
		 * This can mean, for example, invalid CRC32 in headers
		 * or invalid check of uncompressed data.
		 */

	LZMA_BUF_ERROR          = 10,
		/**<
		 * \brief       No progress is possible
		 *
		 * This error code is returned when the coder cannot consume
		 * any new input and produce any new output. The most common
		 * reason for this error is that the input stream being
		 * decoded is truncated or corrupt.
		 *
		 * This error is not fatal. Coding can be continued normally
		 * by providing more input and/or more output space, if
		 * possible.
		 *
		 * Typically the first call to lzma_code() that can do no
		 * progress returns LZMA_OK instead of LZMA_BUF_ERROR. Only
		 * the second consecutive call doing no progress will return
		 * LZMA_BUF_ERROR. This is by design.
		 *
		 * With zlib, Z_BUF_ERROR may be returned even if the
		 * application is doing nothing wrong. The above hack
		 * guarantees that liblzma never returns LZMA_BUF_ERROR
		 * to properly written applications unless the input file
		 * is truncated or corrupt. This should simplify the
		 * applications a little.
		 */

	LZMA_PROG_ERROR         = 11,
		/**<
		 * \brief       Programming error
		 *
		 * This indicates that the arguments given to the function are
		 * invalid or the internal state of the decoder is corrupt.
		 *   - Function arguments are invalid or the structures
		 *     pointed by the argument pointers are invalid
		 *     e.g. if strm->next_out has been set to NULL and
		 *     strm->avail_out > 0 when calling lzma_code().
		 *   - lzma_* functions have been called in wrong order
		 *     e.g. lzma_code() was called right after lzma_end().
		 *   - If errors occur randomly, the reason might be flaky
		 *     hardware.
		 *
		 * If you think that your code is correct, this error code
		 * can be a sign of a bug in liblzma. See the documentation
		 * how to report bugs.
		 */
} lzma_ret;


/**
 * \brief       The `action' argument for lzma_code()
 *
 * After the first use of LZMA_SYNC_FLUSH, LZMA_FULL_FLUSH, or LZMA_FINISH,
 * the same `action' must is used until lzma_code() returns LZMA_STREAM_END.
 * Also, the amount of input (that is, strm->avail_in) must not be modified
 * by the application until lzma_code() returns LZMA_STREAM_END. Changing the
 * `action' or modifying the amount of input will make lzma_code() return
 * LZMA_PROG_ERROR.
 */
typedef enum {
	LZMA_RUN = 0,
		/**<
		 * \brief       Continue coding
		 *
		 * Encoder: Encode as much input as possible. Some internal
		 * buffering will probably be done (depends on the filter
		 * chain in use), which causes latency: the input used won't
		 * usually be decodeable from the output of the same
		 * lzma_code() call.
		 *
		 * Decoder: Decode as much input as possible and produce as
		 * much output as possible. This action provides best
		 * throughput, but may introduce latency, because the
		 * decoder may decode more data into its internal buffers
		 * than that fits into next_out.
		 */

	LZMA_SYNC_FLUSH = 1,
		/**<
		 * \brief       Make all the input available at output
		 *
		 * Normally the encoder introduces some latency.
		 * LZMA_SYNC_FLUSH forces all the buffered data to be
		 * available at output without resetting the internal
		 * state of the encoder. This way it is possible to use
		 * compressed stream for example for communication over
		 * network.
		 *
		 * Only some filters support LZMA_SYNC_FLUSH. Trying to use
		 * LZMA_SYNC_FLUSH with filters that don't support it will
		 * make lzma_code() return LZMA_OPTIONS_ERROR. For example,
		 * LZMA1 doesn't support LZMA_SYNC_FLUSH but LZMA2 does.
		 *
		 * Using LZMA_SYNC_FLUSH very often can dramatically reduce
		 * the compression ratio. With some filters (for example,
		 * LZMA2), finetuning the compression options may help
		 * mitigate this problem significantly.
		 *
		 * Decoders don't support LZMA_SYNC_FLUSH.
		 */

	LZMA_FULL_FLUSH = 2,
		/**<
		 * \brief       Make all the input available at output
		 *
		 * This is like LZMA_SYNC_FLUSH except that this resets the
		 * internal encoder state.
		 *
		 *
		 *
		 * Finishes encoding of the current Data Block. All the input
		 * data going to the current Data Block must have been given
		 * to the encoder (the last bytes can still be pending in
		 * next_in). Call lzma_code() with LZMA_FULL_FLUSH until
		 * it returns LZMA_STREAM_END. Then continue normally with
		 * LZMA_RUN or finish the Stream with LZMA_FINISH.
		 *
		 * This action is supported only by Stream encoder and easy
		 * encoder (which uses Stream encoder). If there is no
		 * unfinished Block, no empty Block is created.
		 */

	LZMA_FINISH = 3
		/**<
		 * \brief       Finish the coding operation
		 *
		 *
		 *
		 *
		 * Finishes the coding operation. All the input data must
		 * have been given to the encoder (the last bytes can still
		 * be pending in next_in). Call lzma_code() with LZMA_FINISH
		 * until it returns LZMA_STREAM_END. Once LZMA_FINISH has
		 * been used, the amount of input must no longer be changed
		 * by the application.
		 *
		 * When decoding, using LZMA_FINISH is optional unless the
		 * LZMA_CONCATENATED flag was used when the decoder was
		 * initialized. When LZMA_CONCATENATED was not used, the only
		 * effect of LZMA_FINISH is that the amount of input must not
		 * be changed just like in the encoder.
		 */
} lzma_action;


/**
 * \brief       Custom functions for memory handling
 *
 * A pointer to lzma_allocator may be passed via lzma_stream structure
 * to liblzma, and some advanced function take pointer lzma_allocator as
 * a separate function argument. The library will use the functions
 * specified in lzma_allocator for memory handling instead of the default
 * malloc() and free().
 *
 * liblzma doesn't make an internal copy of lzma_allocator. Thus, it is
 * OK to change these function pointers in the middle of the coding
 * process, but obviously it must be done carefully to make sure that the
 * replacement `free' can deallocate memory allocated by the earlier
 * `alloc' function(s).
 */
typedef struct {
	/**
	 * \brief       Pointer to custom memory allocation function
	 *
	 * If you don't want a custom allocator, but still want
	 * custom free(), set this to NULL and liblzma will use
	 * the standard malloc().
	 *
	 * \param       opaque  lzma_allocator.opaque (see below)
	 * \param       nmemb   Number of elements like in calloc().
	 *                      liblzma will always set nmemb to 1.
	 *                      This argument exists only for
	 *                      compatibility with zlib and libbzip2.
	 * \param       size    Size of an element in bytes.
	 *                      liblzma never sets this to zero.
	 *
	 * \return      Pointer to the beginning of a memory block of
	 *              size nmemb * size, or NULL if allocation fails
	 *              for some reason. When allocation fails, functions
	 *              of liblzma return LZMA_MEM_ERROR.
	 *
	 * For performance reasons, the allocator should not waste time
	 * zeroing the allocated buffers. This is not only about speed, but
	 * also memory usage, since the operating system kernel doesn't
	 * necessarily allocate the requested memory until it is actually
	 * used. With small input files liblzma may actually need only a
	 * fraction of the memory that it requested for allocation.
	 *
	 * \note        LZMA_MEM_ERROR is also used when the size of the
	 *              allocation would be greater than SIZE_MAX. Thus,
	 *              don't assume that the custom allocator must have
	 *              returned NULL if some function from liblzma
	 *              returns LZMA_MEM_ERROR.
	 */
	void *(*alloc)(void *opaque, size_t nmemb, size_t size);

	/**
	 * \brief       Pointer to custom memory freeing function
	 *
	 * If you don't want a custom freeing function, but still
	 * want a custom allocator, set this to NULL and liblzma
	 * will use the standard free().
	 *
	 * \param       opaque  lzma_allocator.opaque (see below)
	 * \param       ptr     Pointer returned by lzma_allocator.alloc(),
	 *                      or when it is set to NULL, a pointer returned
	 *                      by the standard malloc().
	 */
	void (*free)(void *opaque, void *ptr);

	/**
	 * \brief       Pointer passed to .alloc() and .free()
	 *
	 * opaque is passed as the first argument to lzma_allocator.alloc()
	 * and lzma_allocator.free(). This intended to ease implementing
	 * custom memory allocation functions for use with liblzma.
	 *
	 * If you don't need this, you should set this to NULL.
	 */
	void *opaque;

} lzma_allocator;


/**
 * \brief       Internal data structure
 *
 * The contents of this structure is not visible outside the library.
 */
typedef struct lzma_internal_s lzma_internal;


/**
 * \brief       Passing data to and from liblzma
 *
 * The lzma_stream structure is used for
 *   - passing pointers to input and output buffers to liblzma;
 *   - defining custom memory hander functions; and
 *   - holding a pointer to coder-specific internal data structures.
 *
 * The typical usage
 *
 *  - After allocating lzma_stream (on stack or with malloc()), it must be
 *    initialized to LZMA_STREAM_INIT (see LZMA_STREAM_INIT for details).
 *
 *  - Initialize a coder to the lzma_stream, for example by using
 *    lzma_easy_encoder() or lzma_auto_decoder(). In contrast to zlib,
 *    strm->next_in and strm->next_out are ignored by all initialization
 *    functions, thus it is safe to not initialize them yet. The
 *    initialization functions always set strm->total_in and strm->total_out
 *    to zero.
 *
 *  - Use lzma_code() to do the actual work.
 *
 *  - Once the coding has been finished, the existing lzma_stream can be
 *    reused. It is OK to reuse lzma_stream with different initialization
 *    function without calling lzma_end() first. Old allocations are
 *    automatically freed.
 *
 *  - Finally, use lzma_end() to free the allocated memory.
 *
 * Application may modify values of total_in and total_out as it wants.
 * They are updated by liblzma to match the amount of data read and
 * written, but liblzma doesn't use the values internally.
 */
typedef struct {
	const uint8_t *next_in; /**< Pointer to the next input byte. */
	size_t avail_in;    /**< Number of available input bytes in next_in. */
	uint64_t total_in;  /**< Total number of bytes read by liblzma. */

	uint8_t *next_out;  /**< Pointer to the next output position. */
	size_t avail_out;   /**< Amount of free space in next_out. */
	uint64_t total_out; /**< Total number of bytes written by liblzma. */

	/**
	 * Custom memory allocation functions. Set to NULL to use
	 * the standard malloc() and free().
	 */
	lzma_allocator *allocator;

	/** Internal state is not visible to applications. */
	lzma_internal *internal;

	/**
	 * Reserved space to allow possible future extensions without
	 * breaking the ABI. Excluding the initialization of this structure,
	 * you should not touch these, because the names of these variables
	 * may change.
	 */
	void *reserved_ptr1;
	void *reserved_ptr2;
	uint64_t reserved_int1;
	uint64_t reserved_int2;
	lzma_reserved_enum reserved_enum1;
	lzma_reserved_enum reserved_enum2;

} lzma_stream;


/**
 * \brief       Initialization for lzma_stream
 *
 * When you declare an instance of lzma_stream, you can immediatelly
 * initialize it so that initialization functions know that no memory
 * has been allocated yet:
 *
 *     lzma_stream strm = LZMA_STREAM_INIT;
 *
 * If you need to initialize a dynamically allocated lzma_stream, you can use
 * memset(strm_pointer, 0, sizeof(lzma_stream)). Strictly speaking, this
 * violates the C standard since NULL may have different internal
 * representation than zero, but it should be portable enough in practice.
 * Anyway, for maximum portability, you can use something like this:
 *
 *     lzma_stream tmp = LZMA_STREAM_INIT;
 *     *strm = tmp;
 */
#define LZMA_STREAM_INIT \
	{ NULL, 0, 0, NULL, 0, 0, NULL, NULL, NULL, NULL, 0, 0, 0, 0 }


/**
 * \brief       Encodes or decodes data
 *
 * Once the lzma_stream has been successfully initialized (e.g. with
 * lzma_stream_encoder()), the actual encoding or decoding is done
 * using this function. The application has to update strm->next_in,
 * strm->avail_in, strm->next_out, and strm->avail_out to pass input
 * to and get output from liblzma.
 *
 * See the description of the coder-specific initialization function to find
 * out what `action' values are supported by the coder. See documentation of
 * lzma_ret for the possible return values.
 */
extern lzma_ret lzma_code(lzma_stream *strm, lzma_action action)
		lzma_attr_warn_unused_result;


/**
 * \brief       Frees memory allocated for the coder data structures
 *
 * \param       strm    Pointer to lzma_stream that is at least initialized
 *                      with LZMA_STREAM_INIT.
 *
 * \note        zlib indicates an error if application end()s unfinished
 *              stream. liblzma doesn't do this, and assumes that
 *              application knows what it is doing.
 */
extern void lzma_end(lzma_stream *strm);