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