forked from Imagelibrary/rtems
123 lines
4.0 KiB
C
123 lines
4.0 KiB
C
/*
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* COPYRIGHT (c) 2012 Chris Johns <chrisj@rtems.org>
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*
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* The license and distribution terms for this file may be
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* found in the file LICENSE in this distribution or at
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* http://www.rtems.com/license/LICENSE.
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*/
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/**
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* @file
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*
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* @ingroup rtems_rtl
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*
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* @brief RTEMS Run-Time Linker Object File Compression manages a
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* compressed stream of data.
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*
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* This is a simple interface to the object file cache to stream data from
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* from a compressed object file. There is no ability to seek with the
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* data from a compressed file. The module exists to allocate the output
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* buffer when the loader starts and use the cache buffers will have been
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* allocated.
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*/
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#if !defined (_RTEMS_RTL_OBJ_COMP_H_)
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#define _RTEMS_RTL_OBJ_COMP_H_
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#include <rtems/rtl/rtl-obj-cache.h>
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#ifdef __cplusplus
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extern "C" {
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#endif /* __cplusplus */
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/**
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* The amount of input data read at a time from the file.
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*/
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#define RTEMS_RTL_DECOMP_INPUT_SIZE (256)
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/**
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* The types of supported compression.
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*/
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#define RTEMS_RTL_COMP_NONE (0)
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#define RTEMS_RTL_COMP_LZ77 (1)
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/**
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* The compressed file.
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*/
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typedef struct rtems_rtl_obj_cpmp_s
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{
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rtems_rtl_obj_cache_t* cache; /**< The cache provides the input
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* buffer. */
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int fd; /**< The file descriptor. */
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int compression; /**< The type of compression. */
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off_t offset; /**< The base offset of the buffer. */
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size_t size; /**< The size of the output buffer. */
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size_t level; /**< The amount of data in the buffer. */
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uint8_t* buffer; /**< The buffer */
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uint32_t read; /**< The amount of data read. */
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} rtems_rtl_obj_comp_t;
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/**
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* Return the input level.
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*/
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static inline uint32_t rtems_rtl_obj_comp_input (rtems_rtl_obj_comp_t* comp)
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{
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return comp->read;
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}
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/**
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* Open a compressor allocating the output buffer.
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*
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* @param comp The compressor to initialise.
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* @param size The size of the compressor's output buffer.
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* @retval true The compressor is open.
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* @retval false The compressor is not open. The RTL error is set.
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*/
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bool rtems_rtl_obj_comp_open (rtems_rtl_obj_comp_t* comp,
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size_t size);
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/**
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* Close a compressor.
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*
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* @param comp The compressor to close.
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*/
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void rtems_rtl_obj_comp_close (rtems_rtl_obj_comp_t* comp);
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/**
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* Set the cache and offset in the file the compressed stream starts.
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*
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* @param comp The compressor to set the offset in.
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* @param cache The cache to read the file in by.
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* @param fd The file descriptor. Must be an open file.
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* @param compression The type of compression being streamed.
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* @param offset The offset in the file the compressed stream starts.
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*/
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void rtems_rtl_obj_comp_set (rtems_rtl_obj_comp_t* comp,
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rtems_rtl_obj_cache_t* cache,
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int fd,
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int compression,
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off_t offset);
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/**
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* Read decompressed data. The length contains the amount of data that should
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* be available in the cache and referenced by the buffer handle. It must be
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* less than or equal to the size of the cache. This call will return the
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* amount of data that is available. It can be less than you ask if the offset
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* and size is past the end of the file.
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*
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* @param comp The compressor to read data from.
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* @param buffer The buffer the output is written too.
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* @param length The length of data to read. Can be modified to a
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* lesser value and true is still returned so check it.
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* @retval true The data referenced is in the cache.
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* @retval false The read failed and the RTL error has been set.
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*/
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bool rtems_rtl_obj_comp_read (rtems_rtl_obj_comp_t* comp,
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void* buffer,
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size_t length);
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#ifdef __cplusplus
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}
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#endif /* __cplusplus */
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#endif
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