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/*
* COPYRIGHT (c) 2012 Chris Johns <chrisj@rtems.org>
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.org/license/LICENSE.
*/
/**
* @file
*
* @ingroup rtems_rtl
*
* @brief 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.
*/
#if !defined (_RTEMS_RTL_OBJ_COMP_H_)
#define _RTEMS_RTL_OBJ_COMP_H_
#include <rtems/rtl/rtl-obj-cache.h>
#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */
/**
* The amount of input data read at a time from the file.
*/
#define RTEMS_RTL_DECOMP_INPUT_SIZE (256)
/**
* The types of supported compression.
*/
#define RTEMS_RTL_COMP_NONE (0)
#define RTEMS_RTL_COMP_LZ77 (1)
/**
* The compressed file.
*/
typedef struct rtems_rtl_obj_cpmp_s
{
rtems_rtl_obj_cache_t* cache; /**< The cache provides the input
* buffer. */
int fd; /**< The file descriptor. */
int compression; /**< The type of compression. */
off_t offset; /**< The base offset of the buffer. */
size_t size; /**< The size of the output buffer. */
size_t level; /**< The amount of data in the buffer. */
uint8_t* buffer; /**< The buffer */
uint32_t read; /**< The amount of data read. */
} rtems_rtl_obj_comp_t;
/**
* Return the input level.
*/
static inline uint32_t rtems_rtl_obj_comp_input (rtems_rtl_obj_comp_t* comp)
{
return comp->read;
}
/**
* Open a compressor allocating the output buffer.
*
* @param comp The compressor to initialise.
* @param size The size of the compressor's output buffer.
* @retval true The compressor is open.
* @retval false The compressor is not open. The RTL error is set.
*/
bool rtems_rtl_obj_comp_open (rtems_rtl_obj_comp_t* comp,
size_t size);
/**
* Close a compressor.
*
* @param comp The compressor to close.
*/
void rtems_rtl_obj_comp_close (rtems_rtl_obj_comp_t* comp);
/**
* Set the cache and offset in the file the compressed stream starts.
*
* @param comp The compressor to set the offset in.
* @param cache The cache to read the file in by.
* @param fd The file descriptor. Must be an open file.
* @param compression The type of compression being streamed.
* @param offset The offset in the file the compressed stream starts.
*/
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);
/**
* 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.
*
* @param comp The compressor to read data from.
* @param buffer The buffer the output is written too.
* @param length The length of data to read. Can be modified to a
* lesser value and true is still returned so check it.
* @retval true The data referenced is in the cache.
* @retval false The read failed and the RTL error has been set.
*/
bool rtems_rtl_obj_comp_read (rtems_rtl_obj_comp_t* comp,
void* buffer,
size_t length);
#ifdef __cplusplus
}
#endif /* __cplusplus */
#endif
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