rtl-obj-comp.h File Reference

RTEMS Run-Time Linker Object File Compression manages a compressed stream of data. More...

#include <rtems/rtl/rtl-obj-cache.h>

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Data Structures
struct	rtems_rtl_obj_cpmp_s
	The compressed file. More...

Macros
#define	RTEMS_RTL_DECOMP_INPUT_SIZE   (256)
	The amount of input data read at a time from the file.
#define	RTEMS_RTL_COMP_NONE   (0)
	The types of supported compression.
#define	RTEMS_RTL_COMP_LZ77   (1)

Typedefs
typedef struct rtems_rtl_obj_cpmp_s	rtems_rtl_obj_comp_t
	The compressed file.

Functions
bool	rtems_rtl_obj_comp_open (rtems_rtl_obj_comp_t *comp, size_t size)
	Open a compressor allocating the output buffer. More...
void	rtems_rtl_obj_comp_close (rtems_rtl_obj_comp_t *comp)
	Close a compressor. More...
void	rtems_rtl_obj_comp_set (rtems_rtl_obj_comp_t *comp, rtems_rtl_obj_cache_t *cache, int fd, int compression, off_t offset)
	Set the cache and offset in the file the compressed stream starts. More...
bool	rtems_rtl_obj_comp_read (rtems_rtl_obj_comp_t *comp, void *buffer, size_t length)
	Read decompressed data. More...

Detailed Description

RTEMS Run-Time Linker Object File Compression manages a compressed stream of data.

This is a simple interface to the object file cache to stream data from from a compressed object file. There is no ability to seek with the data from a compressed file. The module exists to allocate the output buffer when the loader starts and use the cache buffers will have been allocated.

Function Documentation

rtems_rtl_obj_comp_close()

void rtems_rtl_obj_comp_close

(

rtems_rtl_obj_comp_t *

comp

)

Close a compressor.

Parameters

comp	The compressor to close.

References rtems_rtl_obj_cpmp_s::buffer, rtems_rtl_obj_cpmp_s::cache, rtems_rtl_obj_cpmp_s::compression, rtems_rtl_obj_cpmp_s::fd, rtems_rtl_alloc_del(), and RTEMS_RTL_ALLOC_OBJECT.

rtems_rtl_obj_comp_open()

bool rtems_rtl_obj_comp_open	(	rtems_rtl_obj_comp_t *	comp,
		size_t	size
	)

Open a compressor allocating the output buffer.

Parameters

comp	The compressor to initialise.
size	The size of the compressor's output buffer.

Return values

true	The compressor is open.
false	The compressor is not open. The RTL error is set.

rtems_rtl_obj_comp_read()

bool rtems_rtl_obj_comp_read	(	rtems_rtl_obj_comp_t *	comp,
		void *	buffer,
		size_t	length
	)

Read decompressed data.

The length contains the amount of data that should be available in the cache and referenced by the buffer handle. It must be less than or equal to the size of the cache. This call will return the amount of data that is available. It can be less than you ask if the offset and size is past the end of the file.

Parameters

comp	The compressor to read data from.
buffer	The buffer the output is written too.
length	The length of data to read. Can be modified to a lesser value and true is still returned so check it.

Return values

true	The data referenced is in the cache.
false	The read failed and the RTL error has been set.

rtems_rtl_obj_comp_set()

void rtems_rtl_obj_comp_set	(	rtems_rtl_obj_comp_t *	comp,
		rtems_rtl_obj_cache_t *	cache,
		int	fd,
		int	compression,
		off_t	offset
	)

Set the cache and offset in the file the compressed stream starts.

Parameters

comp	The compressor to set the offset in.
cache	The cache to read the file in by.
fd	The file descriptor. Must be an open file.
compression	The type of compression being streamed.
offset	The offset in the file the compressed stream starts.

References rtems_rtl_obj_cpmp_s::cache, rtems_rtl_obj_cpmp_s::compression, rtems_rtl_obj_cpmp_s::fd, rtems_rtl_obj_cpmp_s::level, rtems_rtl_obj_cpmp_s::offset, and rtems_rtl_obj_cpmp_s::read.

Referenced by rtems_rtl_obj_comp().