1 ///////////////////////////////////////////////////////////////////////////////
2 //
3 /// \file       simple_private.h
4 /// \brief      Private definitions for so called simple filters
5 //
6 //  Author:     Lasse Collin
7 //
8 //  This file has been put into the public domain.
9 //  You can do whatever you want with this file.
10 //
11 ///////////////////////////////////////////////////////////////////////////////
12 
13 #ifndef LZMA_SIMPLE_PRIVATE_H
14 #define LZMA_SIMPLE_PRIVATE_H
15 
16 #include "simple_coder.h"
17 
18 
19 typedef struct {
20 	/// Next filter in the chain
21 	lzma_next_coder next;
22 
23 	/// True if the next coder in the chain has returned LZMA_STREAM_END.
24 	bool end_was_reached;
25 
26 	/// True if filter() should encode the data; false to decode.
27 	/// Currently all simple filters use the same function for encoding
28 	/// and decoding, because the difference between encoders and decoders
29 	/// is very small.
30 	bool is_encoder;
31 
32 	/// Pointer to filter-specific function, which does
33 	/// the actual filtering.
34 	size_t (*filter)(void *simple, uint32_t now_pos,
35 			bool is_encoder, uint8_t *buffer, size_t size);
36 
37 	/// Pointer to filter-specific data, or NULL if filter doesn't need
38 	/// any extra data.
39 	void *simple;
40 
41 	/// The lowest 32 bits of the current position in the data. Most
42 	/// filters need this to do conversions between absolute and relative
43 	/// addresses.
44 	uint32_t now_pos;
45 
46 	/// Size of the memory allocated for the buffer.
47 	size_t allocated;
48 
49 	/// Flushing position in the temporary buffer. buffer[pos] is the
50 	/// next byte to be copied to out[].
51 	size_t pos;
52 
53 	/// buffer[filtered] is the first unfiltered byte. When pos is smaller
54 	/// than filtered, there is unflushed filtered data in the buffer.
55 	size_t filtered;
56 
57 	/// Total number of bytes (both filtered and unfiltered) currently
58 	/// in the temporary buffer.
59 	size_t size;
60 
61 	/// Temporary buffer
62 	uint8_t buffer[];
63 } lzma_simple_coder;
64 
65 
66 extern lzma_ret lzma_simple_coder_init(lzma_next_coder *next,
67 		const lzma_allocator *allocator,
68 		const lzma_filter_info *filters,
69 		size_t (*filter)(void *simple, uint32_t now_pos,
70 			bool is_encoder, uint8_t *buffer, size_t size),
71 		size_t simple_size, size_t unfiltered_max,
72 		uint32_t alignment, bool is_encoder);
73 
74 #endif
75