0 $li~ hjţ O4?/** * \file lzma/container.h * \brief File formats */ /* * Author: Lasse Collin * * This file has been put into the public domain. * You can do whatever you want with this file. * * See ../lzma.h for information about liblzma as a whole. */ #ifndef LZMA_H_INTERNAL # error Never include this file directly. Use instead. #endif /************ * Encoding * ************/ /** * \brief Default compression preset * * It's not straightforward to recommend a default preset, because in some * cases keeping the resource usage relatively low is more important that * getting the maximum compression ratio. */ #define LZMA_PRESET_DEFAULT UINT32_C(6) /** * \brief Mask for preset level * * This is useful only if you need to extract the level from the preset * variable. That should be rare. */ #define LZMA_PRESET_LEVEL_MASK UINT32_C(0x1F) /* * Preset flags * * Currently only one flag is defined. */ /** * \brief Extreme compression preset * * This flag modifies the preset to make the encoding significantly slower * while improving the compression ratio only marginally. This is useful * when you don't mind wasting time to get as small result as possible. * * This flag doesn't affect the memory usage requirements of the decoder (at * least not significantly). The memory usage of the encoder may be increased * a little but only at the lowest preset levels (0-3). */ #define LZMA_PRESET_EXTREME (UINT32_C(1) << 31) /** * \brief Multithreading options */ typedef struct { /** * \brief Flags * * Set this to zero if no flags are wanted. * * No flags are currently supported. */ uint32_t flags; /** * \brief Number of worker threads to use */ uint32_t threads; /** * \brief Maximum uncompressed size of a Block * * The encoder will start a new .xz Block every block_size bytes. * Using LZMA_FULL_FLUSH or LZMA_FULL_BARRIER with lzma_code() * the caller may tell liblzma to start a new Block earlier. * * With LZMA2, a recommended block size is 2-4 times the LZMA2 * dictionary size. With very small dictionaries, it is recommended * to use at least 1 MiB block size for good compression ratio, even * if this is more than four times the dictionary size. Note that * these are only recommendations for typical use cases; feel free * to use other values. Just keep in mind that using a block size * less than the LZMA2 dictionary size is waste of RAM. * * Set this to 0 to let liblzma choose the block size depending * on the compression options. For LZMA2 it will be 3*dict_size * or 1 MiB, whichever is more. * * For each thread, about 3 * block_size bytes of memory will be * allocated. This may change in later liblzma versions. If so, * the memory usage will probably be reduced, not increased. */ uint64_t block_size; /** * \brief Timeout to allow lzma_code() to return early * * Multithreading can make liblzma to consume input and produce * output in a very bursty way: it may first read a lot of input * to fill internal buffers, then no input or output occurs for * a while. * * In single-threaded mode, lzma_code() won't return until it has * either consumed all the input or filled the output buffer. If * this is done in multithreaded mode, it may cause a call * lzma_code() to take even tens of seconds, which isn't acceptable * in all applications. * * To avoid very long blocking times in lzma_code(), a timeout * (in milliseconds) may be set here. If lzma_code() would block * longer than this number of milliseconds, it will return with * LZMA_OK. Reasonable values are 100 ms or more. The xz command * line tool uses 300 ms. * * If long blocking times are fine for you, set timeout to a special * value of 0, which will disable the timeout mechanism and will make * lzma_code() block until all the input is consumed or the output * buffer has been filled. * * \note Even