Multithreading options. More...

#include <container.h>

Public Attributes
uint32_t	flags
	Flags. More...

uint32_t	threads
	Number of worker threads to use. More...

uint64_t	block_size
	Maximum uncompressed size of a Block. More...

uint32_t	timeout
	Timeout to allow lzma_code() to return early. More...

uint32_t	preset
	Compression preset (level and possible flags) More...

const lzma_filter *	filters
	Filter chain (alternative to a preset) More...

lzma_check	check
	Integrity check type. More...

lzma_reserved_enum	reserved_enum1

lzma_reserved_enum	reserved_enum2

lzma_reserved_enum	reserved_enum3

uint32_t	reserved_int1

uint32_t	reserved_int2

uint32_t	reserved_int3

uint32_t	reserved_int4

uint64_t	reserved_int5

uint64_t	reserved_int6

uint64_t	reserved_int7

uint64_t	reserved_int8

void *	reserved_ptr1

void *	reserved_ptr2

void *	reserved_ptr3

void *	reserved_ptr4

Detailed Description

Multithreading options.

Definition at line 66 of file container.h.

Member Data Documentation

◆ block_size

uint64_t lzma_mt::block_size

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.

Definition at line 104 of file container.h.

Referenced by coder_init().

◆ check

lzma_check lzma_mt::check

Integrity check type.

See check.h for available checks. The xz command line tool defaults to LZMA_CHECK_CRC64, which is a good choice if you are unsure.

Definition at line 160 of file container.h.

Referenced by coder_init().

◆ filters

const lzma_filter* lzma_mt::filters

Filter chain (alternative to a preset)

If this is NULL, the preset above is used. Otherwise the preset is ignored and the filter chain specified here is used.

Definition at line 151 of file container.h.

◆ flags

uint32_t lzma_mt::flags

Flags.

Set this to zero if no flags are wanted.

No flags are currently supported.

Definition at line 74 of file container.h.

Referenced by cmd_descs_generate.Arg::__str__(), and init_encoder().

◆ preset

uint32_t lzma_mt::preset

Compression preset (level and possible flags)

The preset is set just like with lzma_easy_encoder(). The preset is ignored if filters below is non-NULL.

Definition at line 143 of file container.h.

◆ reserved_enum1

lzma_reserved_enum lzma_mt::reserved_enum1

Definition at line 169 of file container.h.

◆ reserved_enum2

lzma_reserved_enum lzma_mt::reserved_enum2

Definition at line 170 of file container.h.

◆ reserved_enum3

lzma_reserved_enum lzma_mt::reserved_enum3

Definition at line 171 of file container.h.

◆ reserved_int1

uint32_t lzma_mt::reserved_int1

Definition at line 172 of file container.h.

◆ reserved_int2

uint32_t lzma_mt::reserved_int2

Definition at line 173 of file container.h.

◆ reserved_int3

uint32_t lzma_mt::reserved_int3

Definition at line 174 of file container.h.

◆ reserved_int4

uint32_t lzma_mt::reserved_int4

Definition at line 175 of file container.h.

◆ reserved_int5

uint64_t lzma_mt::reserved_int5

Definition at line 176 of file container.h.

◆ reserved_int6

uint64_t lzma_mt::reserved_int6

Definition at line 177 of file container.h.

◆ reserved_int7

uint64_t lzma_mt::reserved_int7

Definition at line 178 of file container.h.

◆ reserved_int8

uint64_t lzma_mt::reserved_int8

Definition at line 179 of file container.h.

◆ reserved_ptr1

void* lzma_mt::reserved_ptr1

Definition at line 180 of file container.h.

◆ reserved_ptr2

void* lzma_mt::reserved_ptr2

Definition at line 181 of file container.h.

◆ reserved_ptr3

void* lzma_mt::reserved_ptr3

Definition at line 182 of file container.h.

◆ reserved_ptr4

void* lzma_mt::reserved_ptr4

Definition at line 183 of file container.h.

◆ threads

uint32_t lzma_mt::threads

Number of worker threads to use.

Definition at line 79 of file container.h.

Referenced by coder_init(), and init_encoder().

◆ timeout

uint32_t lzma_mt::timeout

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 with a timeout, lzma_code() might sometimes take somewhat long time to return. No timing guarantees are made.

Definition at line 135 of file container.h.

The documentation for this struct was generated from the following file:

subprojects/xz-5.2.5/src/liblzma/api/lzma/container.h

Public Attributes