lzma_stream Struct Reference

Passing data to and from liblzma. More...

#include <base.h>

Data Fields
const uint8_t *	next_in
size_t	avail_in
uint64_t	total_in
uint8_t *	next_out
size_t	avail_out
uint64_t	total_out
const lzma_allocator *	allocator
	Custom memory allocation functions.
lzma_internal *	internal
uint64_t	seek_pos
	New seek input position for LZMA_SEEK_NEEDED.

Detailed Description

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 handler functions; and
• holding a pointer to coder-specific internal data structures.

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(). Some notes:
  • 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.
  • If the initialization function fails, no memory is left allocated that would require freeing with lzma_end() even if some memory was associated with the lzma_stream structure when the initialization function was called.
• 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. lzma_end() never frees the lzma_stream structure itself.

Application may modify the 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 aren't used for anything else except as a possible return values from lzma_get_progress().

Field Documentation

next_in

const uint8_t* lzma_stream::next_in

Pointer to the next input byte.

avail_in

size_t lzma_stream::avail_in

Number of available input bytes in next_in.

total_in

uint64_t lzma_stream::total_in

Total number of bytes read by liblzma.

next_out

uint8_t* lzma_stream::next_out

Pointer to the next output position.

avail_out

size_t lzma_stream::avail_out

Amount of free space in next_out.

total_out

uint64_t lzma_stream::total_out

Total number of bytes written by liblzma.

allocator

const lzma_allocator* lzma_stream::allocator

Custom memory allocation functions.

In most cases this is NULL which makes liblzma use the standard malloc() and free().

Note

In 5.0.x this is not a const pointer.

internal

lzma_internal* lzma_stream::internal

Internal state is not visible to applications.

seek_pos

uint64_t lzma_stream::seek_pos

New seek input position for LZMA_SEEK_NEEDED.

When lzma_code() returns LZMA_SEEK_NEEDED, the new input position needed by liblzma will be available seek_pos. The value is guaranteed to not exceed the file size that was specified when this lzma_stream was initialized.

In all other situations the value of this variable is undefined.

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

• lzma/base.h