xz/src/liblzma/api/lzma/container.h

/**
 * \file        lzma/container.h
 * \brief       File formats
 *
 * \author      Copyright (C) 1999-2008 Igor Pavlov
 * \author      Copyright (C) 2007-2008 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


/************
 * Encoding *
 ************/

/**
 * \brief       Default compression level for easy encoder
 *
 * It's not straightforward to recommend a default level, because in some
 * cases keeping the resource usage relatively low is more important that
 * getting the maximum compression ratio.
 */
#define LZMA_EASY_LEVEL_DEFAULT 6


/*
 * Flags for easy encoder
 *
 * Currently only one flag is defined.
 */

/**
 * Use significantly slower compression to get marginally better compression
 * ratio. This doesn't affect the memory requirements of the encoder or
 * decoder. This flag is useful when you don't mind wasting time to get as
 * small result as possible.
 *
 * FIXME: Not implemented yet.
 */
#define LZMA_EASY_EXTREME       UINT32_C(0x01)


/**
 * \brief       Calculate rough memory usage of easy encoder
 *
 * This function is a wrapper for lzma_raw_encoder_memusage().
 *
 * \param       level   Compression level
 * \param       flags   Easy encoder flags (usually zero). This parameter is
 *                      needed, because in future some flags may affect the
 *                      memory requirements.
 */
extern uint64_t lzma_easy_encoder_memusage(uint32_t level, uint32_t flags)
		lzma_attr_pure;


/**
 * \brief       Calculate rough memory usage FIXME
 *
 * This function is a wrapper for lzma_raw_decoder_memusage().
 *
 * \param       level   Compression level
 * \param       flags   Easy encoder flags (usually zero). This parameter is
 *                      needed, because in future some flags may affect the
 *                      memory requirements.
 */
extern uint64_t lzma_easy_decoder_memusage(uint32_t level, uint32_t flags)
		lzma_attr_pure;


/**
 * \brief       Initialize .xz Stream encoder using a preset number
 *
 * This function is intended for those who just want to use the basic features
 * if liblzma (that is, most developers out there).
 *
 * \param       strm    Pointer to lzma_stream that is at least initialized
 *                      with LZMA_STREAM_INIT.
 * \param       level   Compression level to use. This selects a set of
 *                      compression settings from a list of compression
 *                      presets. Currently levels from 1 to 9 are defined,
 *                      which match the options -1 .. -9 of the xz command
 *                      line tool.
 * \param       flags   Flags that can finetune the compression preset.
 *                      In most cases, no flags are wanted, and this
 *                      parameter is zero.
 * \param       check   Integrity check type to use. See check.h for available
 *                      checks. If you are unsure, use LZMA_CHECK_CRC32.
 *
 * \return      - LZMA_OK: Initialization succeeded. Use lzma_code() to
 *                encode your data.
 *              - LZMA_MEM_ERROR: Memory allocation failed. All memory
 *                previously allocated for *strm is now freed.
 *              - LZMA_OPTIONS_ERROR: The given compression level is not
 *                supported by this build of liblzma.
 *              - LZMA_UNSUPPORTED_CHECK: The given check type is not
 *                supported by this liblzma build.
 *              - LZMA_PROG_ERROR: One or more of the parameters have values
 *                that will never be valid. For example, strm == NULL.
 *
 * If initialization succeeds, use lzma_code() to do the actual encoding.
 * Valid values for `action' (the second argument of lzma_code()) are
 * LZMA_RUN, LZMA_SYNC_FLUSH, LZMA_FULL_FLUSH, and LZMA_FINISH. In future,
 * there may be compression levels or flags that don't support LZMA_SYNC_FLUSH.
 */
extern lzma_ret lzma_easy_encoder(lzma_stream *strm,
		uint32_t level, uint32_t flags, lzma_check check)
		lzma_attr_warn_unused_result;


/**
 * \brief       Initialize .xz Stream encoder using a custom filter chain
 *
 * \param       strm    Pointer to properly prepared lzma_stream
 * \param       filters Array of filters. This must be terminated with
 *                      filters[n].id = LZMA_VLI_UNKNOWN. There must
 *                      be 1-4 filters, but there are restrictions on how
 *                      multiple filters can be combined. FIXME Tell where
 *                      to find more information.
 * \param       check   Type of the integrity check to calculate from
 *                      uncompressed data.
 *
 * \return      - LZMA_OK: Initialization was successful.
 *              - LZMA_MEM_ERROR
 *              - LZMA_OPTIONS_ERROR
 *              - LZMA_PROG_ERROR
 */
extern lzma_ret lzma_stream_encoder(lzma_stream *strm,
		const lzma_filter *filters, lzma_check check)
		lzma_attr_warn_unused_result;


/**
 * \brief       Initialize .lzma encoder (legacy file format)
 *
 * The .lzma format is sometimes called the LZMA_Alone format, which is the
 * reason for the name of this function. The .lzma format supports only the
 * LZMA1 filter. There is no support for integrity checks like CRC32.
 *
 * Use this function if and only if you need to create files readable by
 * legacy LZMA tools such as LZMA Utils 4.32.x. Moving to the .xz format
 * is strongly recommended.
 *
 * FIXME: Dictionary size limit?
 *
 * The valid action values for lzma_code() are LZMA_RUN and LZMA_FINISH.
 * No kind of flushing is supported, because the file format doesn't make
 * it possible.
 *
 * \return      - LZMA_OK
 *              - LZMA_MEM_ERROR
 *              - LZMA_OPTIONS_ERROR // FIXME
 *              - LZMA_PROG_ERROR
 */
extern lzma_ret lzma_alone_encoder(
		lzma_stream *strm, const lzma_options_lzma *options)
		lzma_attr_warn_unused_result;


/************
 * Decoding *
 ************/

/**
 * This flag makes lzma_code() return LZMA_NO_CHECK if the input stream
 * being decoded has no integrity check. Note that when used with
 * lzma_auto_decoder(), all .lzma files will trigger LZMA_NO_CHECK
 * if LZMA_TELL_NO_CHECK is used.
 */
#define LZMA_TELL_NO_CHECK              UINT32_C(0x01)


/**
 * This flag makes lzma_code() return LZMA_UNSUPPORTED_CHECK if the input
 * stream has an integrity check, but the type of the integrity check is not
 * supported by this liblzma version or build. Such files can still be
 * decoded, but the integrity check cannot be verified.
 */
#define LZMA_TELL_UNSUPPORTED_CHECK     UINT32_C(0x02)


/**
 * This flag makes lzma_code() return LZMA_GET_CHECK as soon as the type
 * of the integrity check is known. The type can then be got with
 * lzma_get_check().
 */
#define LZMA_TELL_ANY_CHECK             UINT32_C(0x04)


/**
 * This flag enables decoding of concatenated files with file formats that
 * allow concatenating compressed files as is. From the formats currently
 * supported by liblzma, only the .xz format allows concatenated files.
 * Concatenated files are not allowed with the legacy .lzma format.
 *
 * This flag also affects the usage of the `action' argument for lzma_code().
 * When LZMA_CONCATENATED is used, lzma_code() won't return LZMA_STREAM_END
 * unless LZMA_FINISH is used as `action'. Thus, the application has to set
 * LZMA_FINISH in the same way as it does when encoding.
 *
 * If LZMA_CONCATENATED is not used, the decoders still accept LZMA_FINISH
 * as `action' for lzma_code(), but the usage of LZMA_FINISH isn't required.
 */
#define LZMA_CONCATENATED               UINT32_C(0x08)


/**
 * \brief       Initialize .xz Stream decoder
 *
 * \param       strm        Pointer to properly prepared lzma_stream
 * \param       memlimit    Rough memory usage limit as bytes
 *
 * \return      - LZMA_OK: Initialization was successful.
 *              - LZMA_MEM_ERROR: Cannot allocate memory.
 *              - LZMA_OPTIONS_ERROR: Unsupported flags
 */
extern lzma_ret lzma_stream_decoder(
		lzma_stream *strm, uint64_t memlimit, uint32_t flags)
		lzma_attr_warn_unused_result;


/**
 * \brief       Decode .xz Streams and .lzma files with autodetection
 *
 * This decoder autodetects between the .xz and .lzma file formats, and
 * calls lzma_stream_decoder() or lzma_alone_decoder() once the type
 * of the input file has been detected.
 *
 * \param       strm        Pointer to properly prepared lzma_stream
 * \param       memlimit    Rough memory usage limit as bytes
 * \param       flags       Bitwise-or of flags, or zero for no flags.
 *
 * \return      - LZMA_OK: Initialization was successful.
 *              - LZMA_MEM_ERROR: Cannot allocate memory.
 *              - LZMA_OPTIONS_ERROR: Unsupported flags
 */
extern lzma_ret lzma_auto_decoder(
		lzma_stream *strm, uint64_t memlimit, uint32_t flags)
		lzma_attr_warn_unused_result;


/**
 * \brief       Initializes decoder for .lzma file
 *
 * Valid `action' arguments to lzma_code() are LZMA_RUN and LZMA_FINISH.
 * There is no need to use LZMA_FINISH, but allowing it may simplify
 * certain types of applications.
 *
 * \return      - LZMA_OK
 *              - LZMA_MEM_ERROR
 */
extern lzma_ret lzma_alone_decoder(lzma_stream *strm, uint64_t memlimit)
		lzma_attr_warn_unused_result;