/** * \file lzma/easy.h * \brief Easy to use encoder initialization * * \author Copyright (C) 1999-2006 Igor Pavlov * \author Copyright (C) 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 instead. #endif /** * \brief Compression level names for lzma_easy_* functions * * At the moment, all the compression levels support LZMA_SYNC_FLUSH. * In future there may be levels that don't support LZMA_SYNC_FLUSH. * However, the LZMA_SYNC_FLUSH support won't be removed from the * existing compression levels. * * \note If liblzma is built without encoder support, or with some * filters disabled, some of the compression levels may be * unsupported. In that case, the initialization functions * will return LZMA_HEADER_ERROR. */ typedef enum { LZMA_EASY_COPY, /**< * No compression; the data is just wrapped into .lzma * container. */ LZMA_EASY_LZMA_1, /**< * LZMA filter with fast compression (fast in terms of LZMA). * If you are interested in the exact options used, see * lzma_preset_lzma[0]. Note that the exact options may * change between liblzma versions. * * At the moment, the command line tool uses these settings * when `lzma -1' is used. In future, the command line tool * may default to some more complex way to determine the * settings used e.g. the type of files being compressed. * * LZMA_EASY_LZMA_2 is equivalent to lzma_preset_lzma[1] * and so on. */ LZMA_EASY_LZMA_2, LZMA_EASY_LZMA_3, LZMA_EASY_LZMA_4, LZMA_EASY_LZMA_5, LZMA_EASY_LZMA_6, LZMA_EASY_LZMA_7, LZMA_EASY_LZMA_8, LZMA_EASY_LZMA_9, } lzma_easy_level; /** * \brief Default compression level for Data Blocks * * Data Blocks contain the actual compressed data. 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_DEFAULT LZMA_EASY_LZMA_7 /** * \brief Default compression level for Metadata Blocks * * Metadata Blocks are present only in Multi-Block Streams. Metadata Blocks * contain the Extra Records (if any) and some book-keeping data that is * used by decoders. */ #define LZMA_EASY_METADATA_DEFAULT LZMA_EASY_LZMA_3 /** * \brief Calculates rough memory requirements of a compression level * * This function is a wrapper for lzma_memory_usage(), which is declared * in lzma/filter.h. * * \return Approximate memory usage of the encoder with the given * compression level in mebibytes (value * 1024 * 1024 bytes). * On error (e.g. compression level is not supported), * UINT32_MAX is returned. */ extern uint32_t lzma_easy_memory_usage(lzma_easy_level level); /** * \brief Initializes Single-Block .lzma Stream encoder * * This function is intended for those who just want to use the basic LZMA * features (that is, most developers out there). Lots of assumptions are * made, which are correct for most situations or at least good enough. * * \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. * * \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_HEADER_ERROR: The given compression level is not * supported by this build of liblzma. * * 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, and LZMA_FINISH. In future, there may be * compression levels that don't support LZMA_SYNC_FLUSH. */ extern lzma_ret lzma_easy_encoder_single( lzma_stream *strm, lzma_easy_level level); /** * \brief Initializes Multi-Block .lzma Stream encoder * * If you want to be able to store Extra Records or want to be able to use * LZMA_FULL_FLUSH, you need to create a Multi-Block Stream. * * \param strm Pointer to lzma_stream that is at least initialized * with LZMA_STREAM_INIT. * \param level Compression level to use for the data being encoded. * \param metadata_level * Compression level to use for Metadata Blocks. * Metadata Blocks contain the Extra Records (if any) * and some book-keeping data that is used by decoders. * \param header Pointer to a list of Extra Records to be stored to * the Header Metadata Block. Set this to NULL to omit * Header Metadata Block completely. The list must be * kept available until the encoding has finished. * \param footer Pointer to a list of Extra Records to be stored to * the Footer Metadata Block. Set this to NULL if you * don't want to store any Extra Records (the Footer * Metadata Block will still be written for other * reasons.) The list must be kept available until * the encoding has finished. * * \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_HEADER_ERROR: The given compression level is not * supported by this build of liblzma. * * 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 that don't support LZMA_SYNC_FLUSH. * LZMA_FULL_FLUSH will always work with all compression levels. */ extern lzma_ret lzma_easy_encoder_multi(lzma_stream *strm, lzma_easy_level level, lzma_easy_level metadata_level, const lzma_extra *header, const lzma_extra *footer);