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      1 // SPDX-License-Identifier: 0BSD
      2 
      3 ///////////////////////////////////////////////////////////////////////////////
      4 //
      5 /// \file       simple_private.h
      6 /// \brief      Private definitions for so called simple filters
      7 //
      8 //  Author:     Lasse Collin
      9 //
     10 ///////////////////////////////////////////////////////////////////////////////
     11 
     12 #ifndef LZMA_SIMPLE_PRIVATE_H
     13 #define LZMA_SIMPLE_PRIVATE_H
     14 
     15 #include "simple_coder.h"
     16 
     17 
     18 typedef struct {
     19 	/// Next filter in the chain
     20 	lzma_next_coder next;
     21 
     22 	/// True if the next coder in the chain has returned LZMA_STREAM_END.
     23 	bool end_was_reached;
     24 
     25 	/// True if filter() should encode the data; false to decode.
     26 	/// Currently all simple filters use the same function for encoding
     27 	/// and decoding, because the difference between encoders and decoders
     28 	/// is very small.
     29 	bool is_encoder;
     30 
     31 	/// Pointer to filter-specific function, which does
     32 	/// the actual filtering.
     33 	size_t (*filter)(void *simple, uint32_t now_pos,
     34 			bool is_encoder, uint8_t *buffer, size_t size);
     35 
     36 	/// Pointer to filter-specific data, or NULL if filter doesn't need
     37 	/// any extra data.
     38 	void *simple;
     39 
     40 	/// The lowest 32 bits of the current position in the data. Most
     41 	/// filters need this to do conversions between absolute and relative
     42 	/// addresses.
     43 	uint32_t now_pos;
     44 
     45 	/// Size of the memory allocated for the buffer.
     46 	size_t allocated;
     47 
     48 	/// Flushing position in the temporary buffer. buffer[pos] is the
     49 	/// next byte to be copied to out[].
     50 	size_t pos;
     51 
     52 	/// buffer[filtered] is the first unfiltered byte. When pos is smaller
     53 	/// than filtered, there is unflushed filtered data in the buffer.
     54 	size_t filtered;
     55 
     56 	/// Total number of bytes (both filtered and unfiltered) currently
     57 	/// in the temporary buffer.
     58 	size_t size;
     59 
     60 	/// Temporary buffer
     61 	uint8_t buffer[];
     62 } lzma_simple_coder;
     63 
     64 
     65 extern lzma_ret lzma_simple_coder_init(lzma_next_coder *next,
     66 		const lzma_allocator *allocator,
     67 		const lzma_filter_info *filters,
     68 		size_t (*filter)(void *simple, uint32_t now_pos,
     69 			bool is_encoder, uint8_t *buffer, size_t size),
     70 		size_t simple_size, size_t unfiltered_max,
     71 		uint32_t alignment, bool is_encoder);
     72 
     73 #endif
     74